Software Technology for “Battery protection for implantable medical devices”

Medical Device – Yuping He, David K. L. Peterson, Boston Scientific Neuromodulation Corp

Abstract for “Battery protection for implantable medical devices”

It is described as “circuitry that can be used to charge and protect a rechargeable battery even at a zero-voltage state.” This is especially useful for implantable medical devices. There are two charging paths in the circuit. One is for trickle charging and the other for charging the battery at higher currents. The first trickle-charging pathway uses a passive diode, which allows for trickle charging even if the battery voltage is too low to allow reliable gating. A second path that charges at higher currents uses a gateable switch (preferably a PMOS semiconductor) when the voltage is higher so the switch can be gated more consistently. The second diode is used between the two charging paths to prevent any leakage to substrates through the gateable switch. The switch couples the load to the battery, with preferably a second switch that is specifically designed for decoupling the load.

Background for “Battery protection for implantable medical devices”

“Implantable stimulation device generate and deliver electrical stimuli for the treatment of various biological disorders. These include pacemakers to treat cardiac arrhythmia and defibrillators that treat cardiac fibrillation. Cochlear stimulators are used to treat blindness. Muscle stimulators are used to produce coordinated limb movement. Spinal cord stimulators can be used to treat chronic pain. Cortical and deep brain stimulators can be used to treat motor and psychological disorders. Other neural stimulators may also be used to treat incontine, sleep a, shoulder sublaxation and to relieve symptoms such as apneapneapneapnea and to provide s to reduce hypnea and to help with a. Although the present invention could be applicable to all of these applications, the following description will focus on its use within a Spinal Cord Stimulation system (SCS), such as the one disclosed in U.S. Pat. No. No.

Spinal cord stimulation is an accepted clinical method to reduce pain in some populations. A typical SCS system includes an Implantable Pulse Generator, Radio-Frequency, or Radio-Frequency transmitter and receiver, electrodes and at least one lead. Optionally, there may be at least one lead extension. The electrodes are located at the distal end the electrode lead and are usually implanted along the spinal cord’s dura. The IPG or the RF transmitter generates electric pulses which are sent through the electrodes to nerve fibers in the spinal column. The individual electrode contacts (the “electrodes”) are what you see. To create an electrode array, the contacts (the?electrodes?) are placed in a particular arrangement. Each electrode is connected to its individual wires by connecting one or more electrode leads. The electrode leads exit the spine and attach to one or several electrode lead extensions. The electrode lead extensions are then tunneled around the patient’s torso to a subcutaneous pocket, where the IPG/RF transceiver can be implanted. Alternately, the electrode lead can be connected directly to the IPG/RF transceiver. U.S. Pat. provides examples of other SCS systems as well as other stimulation systems. Nos. Nos. Implantable pulse generators, which are active devices, require energy to operate, such as an implanted battery, or external power source.

An IPG requires electrical power to function. This should be obvious. This power can be supplied in a variety of ways. For example, an external charger may provide EM induction or a rechargeable, non-rechargeable battery. Other options include using an external charger or electromagnetic (EM) induction. These and other methods are further discussed in U.S. Pat. No. 6,553,263 (?the ‘263 patent? 6,553,263 (?the ‘263 patent) is incorporated by reference in its entirety. The most popular of these options is to use an IPG battery, either a lithium ion or a polymer battery. A rechargeable battery such as a lithium-ion or a polymer battery can usually provide enough power to run an IPG for several days without needing to be charged. EM induction can be used to recharge the IPG. An external charger sends EM fields to the IPG. The external charger can be used to charge the IPG’s battery when it is low.

FIG. 1 shows the basics of such an invention. 1. This is a description of the main contents of the ‘263 Patent. The system includes the relevant parts of the external charger 208 as well as IPG 100. A coil 279 within the charger 208 generates an EM field 290 that can be percutaneously transmitted through a patient’s flesh. 278 An external charger 208 can be powered using any known method, such as a battery or plugging into a wall socket. Another coil 270 meets the EM field 290 at the IPG 100 and in this coil 270 an AC voltage is induced. This AC voltage is then converted to a DC voltage at rectifier 682. It may also include a standard bridge circuit. The EM field 290 may also include data telemetry, but this information is not relevant to the present disclosure. The rectified DC voltage is then sent to the charge controller 684. This control generally operates to regulate the DC voltage, and produce a constant voltage or constant current output to recharge the battery 180. The battery voltage Vbat is a factor that determines the output of the charge regulator 684. This affects how aggressively the controller charges the battery 180. The charge controller 684 can also report the battery 180’s status to the external charger 208 via back-telemetry using coil270. However, this function is not relevant to this disclosure so it is not discussed further.

“The output from the charge controller 684 can be met by two switches 701,702, which prevent the battery 180’s over-charging and over-discharging. These transistors are N channel transistors. They will be?on?, as shown. These transistors are N-channel transistors, which can connect the output of the charge controller 684 to the battery 180 if their gates are biased. The battery protection circuit 686 controls these gates. It receives the voltage and current, Ibat, and Vbat as control signals. This will be discussed in more detail later. The battery protection circuit 686 will, for example, turn off the gate 701 of the overcharging transistor 701 if the battery 180 displays too high a voltage to prevent it from charging further. To further protect the battery against high current events, a fuse may be placed between the transistors 701, 702 or 180 (not shown). The battery 180 is connected to the IPG 100’s load switch 504, which connects it to the electrode stimulation circuitry. This circuitry powers the circuits that the battery 180 eventually powers. A load switch 504 is used to couple the battery 180 to these loads. This can protect the battery 180 from any adverse effects. The load switch 504 may be part of the charge controller 684. However, it is not necessary.

“The charging circuitry 684, as discussed in the ‘263 patent above, can charge the battery 180 in a variety of ways depending on the state of the battery voltage, Vbat. This selective charging of the battery 180, especially when it is lithium-ion-based, is advantageous for safe charging. This safe charging scheme charges the battery 180 at lower currents when Vbat is low. It charges higher currents at safer levels when Vbat is high.

Consider an embodiment where Vbat=4.2V is the nominal voltage for battery 180. The charge controller 684 will?trickle if Vbat=2.5V. The battery 180 can be charged with a low current, such as Ibat=10mA. Higher charging currents can be used as the battery charges and Vbat increases. The charge controller 684 may set a 50 mA charging current if Vbat is above 2.5V. The charge controller 684 can continue charging the battery 180 once the nominal voltage of 2.25V has been reached. This is done by providing a constant voltage on its output instead of a constant current. As the charging process continues, it will cause a gradual decline in the battery current. FIG. illustrates the relationship between Vbat (battery charging) and Ibat. 2. These voltage and current values are only examples. Other parameters may be appropriate depending on the system. You can also use more than one level of charging current, such as 10 mA or 25 mA respectively, in a stair-step fashion.

“The battery protection circuit 686 protects the battery against potential damage while charging. It disconnects the battery 684 from the charge controller 684. To prevent further charging, Vbat is disengaged by the battery protection circuit 686 if it exceeds a safe voltage (e.g., greater that 4.2V). To prevent the battery from being discharged, the over-discharge transistor 702 will be disabled if the battery voltage falls below a predetermined level or if Ibat is higher than a predetermined limit. Although two transistors 701 and 702 are controlled by the battery protection circuit 686, a single disable protection transistor may be used to disable the battery 180 when over-charging or over-discharging is done. To protect the components from adverse voltages or currents, the load switch 504 could be used to control it.

“While the charging circuitry and protection circuitry in FIG. Although FIG. 1’s charging and protection circuitry is compatible, it may not function properly at low battery voltages. The battery protection circuit 686, as described in the ‘263 Patent, is powered by Vbat. This means that when Vbat drops to zero Volts, the battery protection circuitry 686 might not work as intended. It is important to note that Vbat can be very low and the battery 180 needs to charge. The battery protection circuit 686 must be capable of turning transistors 701 & 702 on. Otherwise, the charging controller 684 won’t be able pass an Ibat charging current to the battery. The battery protection circuit 686 might have trouble generating enough voltage to turn the gates of N-channel transistors 701 or 702. However, Ibat can be low. The battery protection circuitry 686 must produce a voltage that is higher than Vgs for transistors. This refers to the potential difference between source and gate of the transistors. The battery protection circuitry must be capable of producing a gate voltage that exceeds Vt, given the source voltages at the transistors. The battery protection circuit 686 might not be able produce the necessary high gate voltage to turn transistors 701 or 702 on if Vbat falls below this threshold voltage.

“Should this happen, the battery 180 will not be charged even though Vbat may be low, and therefore the battery 180 will need to charge. FIG. Vbat below zero Volts, or very close to zero Volts, can cause 1 to fail. This would indicate that the IPG 100 may fail in the worst possible scenario. If implanted in a patient it could require surgical removal and replacement. This is unfortunate because IPGs can be implanted in patients who cannot be relied on to charge them properly. The risk of a dead battery is real.

“As such, it would be advantageous to have improved circuitry and techniques that protect and recover zero-Volt batteries from implantable medical devices. These solutions are available in this document.

The invention discloses circuitry that can be used to charge and protect a rechargeable battery from zero voltage. It is especially useful in implantable medical devices. There are two charging paths. One is for trickle charging the batteries at a low current, when the voltage is below a threshold. The second is for charging the battery at higher currents, when the voltage is higher than a certain threshold. The first trickle-charging pathway uses a passive diode to allow trickle charging, even though the battery voltage is not high enough for reliable gating. A second path charges the battery at higher currents when the voltage is higher so that the switch can be gated more consistently. The second diode is used between the two charging paths to prevent any leakage to substrates through the gateable switch. The switch couples the load to the battery, with a second switch preferably used for decoupling.

The following description is the best way to carry out the invention. This description should not be taken as a limitation of the invention’s principles. It is important to refer to the claims and equivalents when determining the scope of the invention.

“Before we discuss the battery protection and zero Volt recovery aspects, which are the main focus of this disclosure. The circuitry, structure and function of an implantable stimulation device in which the disclosed technique can be used are set forth for completeness with regard to FIGS. 3-6. The implantable stimulator device disclosed may include an implantable pulse generator, or similar electrical stimulator/or sensor that can be used in a variety of stimulation systems. The following description focuses on the use of the invention in a spinal cord stimulation system (SCS). It is important to understand that the invention does not limit itself. The invention can be used with any type or implantable electrical circuitry that would benefit from enhanced battery protection and zero Volt recovery techniques. The present invention can be used in a pacemaker or implantable pump. It may also be used in a cochlear or retinal stimulator. A stimulator that produces coordinated limb movement, cortical or deep-brain stimulator or any other stimulator designed to treat urinary incontinence or sleep apnea. The technique is also suitable for use in non-medical devices and/or systems that do not require battery recovery or protection.

“Turning first, FIG. 3. A block diagram shows the components of an exemplary SCS-system in which the invention can be used. These components can be divided into three categories: surgical components 30, external components 20, or implantable components 10. FIG. FIG. 3 shows the implantable components 10. They include an implantable pulse generator 100, an electrode array 110 and, as needed, a lead extension 120. The extension 120 can be used to connect the electrode array 110 and the IPG 100. The IPG 100 is an example embodiment. This will be described in greater detail below with reference to FIG. 5 or 6, may comprise a rechargeable, multi-channel, telemetry-controlled, pulse generator housed in a rounded high-resistivity titanium alloy case to reduce eddy current heating during the inductive charging process. The IPG 100 can provide electrical stimulation using a variety of electrodes. E1 through E16 are included in the electrode array 110.

“In this context, the IPG 100 could include stimulating electrical circuitry (or?stimulating electronics). The IPG 100 may include a power source (e.g., a rechargeable batteries) and a telemetry device, which are particularly relevant for embodiments of the invention. The IPG 100 is typically placed in a pocket surgically made in the abdomen or at the top of your buttocks. You can also place it in other parts of your body. The IPG 100 is attached to the lead system. This includes the lead extension 120 and the electrode array 110. For example, the lead extension 120 may be tunneled to the spinal column. After the trial stimulation period has ended, the lead system 110 or lead extension 120 will be permanently implanted. The IPG 100, on the other hand, can be replaced if it fails.

“As seen best in FIG. FIG. 4 and FIG. 3. The electrode array 110 and associated lead system interface typically with the implantable pulse generator 100 (IPG), 100 via the lead extension 120. An external trial stimulator 140 may be connected to the electrode array 110 via a percutaneous extension 132 or external cable 134. The IPG 100’s pulse generation circuitry is similar to the external trial stimulator 140. It is used for a trial period of 7-10 days after the electrode array is implanted.

“Still with reference FIGS. “Still with reference to FIGS. This control allows the IPG 100’s turn on and off. It also allows stimulation parameters (e.g. pulse amplitude, width, rate) to be set by patients or clinicians within prescribed limits. Through another link 205? (e.g. an infra-red link), the HHP 202 can be connected to the external trial stimulator 140. An external programmer (CP), 204 is recommended for the programming of the IPG 100. 3.) may also be handheld and may be connected to the IPG 100 via link 201a or indirectly via the HHP202. A non-invasively connected external charger 208 with the IPG 100 via link 290, e.g. an inductive link allows energy stored or made available to the charger208 to be coupled into a rechargeable battery 180 contained within the IPG 100.

“Turning next, FIG. 5 shows a block diagram that illustrates the main components in one embodiment of an implantable pace generator (IPG 100). Other embodiments of this invention could also be used. FIG. FIG. 5 shows the IPG, which includes a microcontroller 160 that is connected to 162 of the memory circuitry. The?C 160 is typically composed of a microprocessor with associated logic circuitry. These circuits, along with control logic circuits 166, 168 and an oscillator/clock circuit 164, create the necessary control signals and status signals that allow the?C 160 control the IPG’s operation in accordance to a chosen operating program and stimulation parameters. (A ?microcontroller? as used herein should be understood as any integrated device capable of processing signals in the IPG, including traditional microcontrollers, microprocessors, or other signal processors, including those that are application-specific, such as ASIC chips).”

“The operating program, as well as the stimulation parameters, are telemetered from the IPG 100 to antenna 250. They are then processed via RF-telemetry circuitry172 and stored in the memory 162. The RF-telemetry circuitry 172 modifies the signal it receives via the HHP 202 and CP 204 in order to recover the operating programme and/or stimulation parameters. The antenna 250 receives signals and passes them through the transmit/receive button 254 to amplifiers or filters 258. The received signals are then demodulated (262), using Frequency Shift Keying demodulation, and sent to the microcontroller 160 for further processing or storage. The RF-telemetry circuitry 172 transmits information to the HHP 202 and CP 204. This allows them to update their status in some way. The microcontroller 160 then sends the relevant data to the transmission drivers 256. There the carrier is modulated with the data and amplified to transmit. The transmit/receive button 254 would be used to communicate with the transmission driver 256. This in turn drives the data to antenna 250 for broadcast.

“The microcontroller 160 can be further connected to the monitoring circuits 173 via bus 173. Monitoring circuits 174 monitor various points 175 in the IPG 100. They include power supply voltages, current values and temperature. . . EN and similar. Informational data that is sensed by the monitoring circuit 173 may be sent to an external location (e.g., non-implanted) via telemetry circuitry 172 via coil 170.

The operating power of the IPG 100 can be obtained from a rechargeable source 180. This could include a lithium-ion, lithium-ion polymer, or both. The 180-volt rechargeable battery provides unregulated voltage for power circuits 182. The power circuits 182 generate various voltages 184. Some of these are regulated, others not, depending on the requirements of the IPG 100. Preferably, the battery 180 can be charged using an electromagnetic field generated by an external portable charger (FIGS. As noted, 1, 3, The IPG 100 is placed close to the charger 208, e.g., about 100 cm away. An electromagnetic field from the portable charger induces a current in the charging coil 270 (even though the patient’s skin). As explained in the Background, this current is rectified and controlled to charge the battery 180. The charging circuitry also includes charging telemetry circuitry 272, used by the IPG 100 to notify the portable charger 208 of full battery status and when it can be turned off.

“In an exemplary embodiment, any N electrode may be assigned to up k possible groups/?channels. In one preferred embodiment, k can equal four. Any of the N electrodes may operate in any of the k channels, or be integrated into, them. The channel indicates which electrodes will synchronously supply or sink current in order to stimulate the tissue. The HHP 202 can control the amplitudes and polarities for electrodes in a channel. The CP 204’s external programming software allows you to program parameters such as electrode polarity, amplitude and pulse rate for each channel.

The N programmable electrodes have the ability to be programmed to either have a positive (sourcing current), a negative (sinking curent), or off (no present) polarity in any one of the k channels. Each of the N electrodes may operate in either a bipolar or multipolar mode. For example, two or more electrode contacts can be grouped together to source/sink the current simultaneously. Each of the N electrodes may also operate in a monopolar mode, where the electrode contacts associated to a channel can be configured as cathodes (negative) and the case electrode (i.e. the IPG case), is configured as an anide (positive).

“Further the amplitude or source of the current pulse that is sunk or sourced to an electrode contact can be programmed to one or more discrete current levels. For example, between 0 and?10mA in steps of 0.01 mA. The pulse width of current pulses can be adjusted in convenient increments. For example, it is possible to adjust the pulse width from 0 to 1 microseconds (ms), in increments of 10 microseconds. The pulse rate can be adjusted within acceptable limits. For example, it could be set to 0 to 1000 Hz. Other features that can be programmed include slow start/end ramping and burst stimulation cycling (on/off for X time) as well as open or closed loop sensing mode.

The stimulation pulses generated using the IPG 100 could be charged balanced. The stimulation pulses generated by the IPG 100 may be charged balanced. This means that the stimulus pulse’s positive charge is countered with a negative charge. Coupler capacitors Cx can achieve the desired charge balance by providing a passive discharge capacitor that produces the required charge-balancing condition. To achieve the desired charge balance condition, you can also use active biphasic and multi-phasic pulses that have balanced positive and negative phases.

The IPG 100 can control the currents at each of the N electrodes. The control of the digital-to-analog current circuitry 186 with the microcontroller 160 and the timer logic 168 allows each electrode contact, together with the control logic 166, and logic 168 to pair or group other electrode contacts to adjust the polarity, amplitude and rate at which the current stimulus pulses are delivered.

“As shown at FIG. 5 circuitry in the IPG 100 can be implemented on one application-specific integrated circuit (ASIC). 190. The IPG 100 is compact and can be easily housed in a hermetically sealed case. N feedthroughs may be included in the IPG 100 to allow individual electrical contact from the sealed case. The N electrodes are located outside the case.

The IPG 100 can be used in surgery, as described earlier. It may be placed in the abdomen, or at the top of your buttocks. The lead system is meant to last forever, but the IPG 100 can be removed and replaced if it fails.

The IPG 100’s telemetry features allow for the monitoring of the IPG 100’s status. The HHP 202 or CP 204 can initiate a programming session using the IPG 100. This allows the external programmer to calculate the expected time of recharge. Back-telemetry confirms that any changes to the current stimulus parameters have been received and are implemented within the implant system. All programmable settings within the implant system 10, which are available for interrogation by an external programmer, can be uploaded to one or several external programmers.

“Turning next FIG. 6. A hybrid block diagram of an alternate embodiment of the IPG 100? Illustration of the IPG 100? What is the IPG 100? The IPG 100 can house both digital and analog dies or integrated circuits (ICs), and may be contained in one hermetically sealed rounded case with a maximum diameter of approximately 45 mm and thickness of around 10 mm. Many of the circuits in the IPG 100 are identical or similar to the ones shown in FIG. Many of the circuits in the IPG 100 are similar or identical to those shown in FIG. 5. IPG 100? Includes a processor chip 160?, and an RF telemetry circuit 172? (typically made with discrete components), a processor die 160?, an RF telemetry circuit 172?, and a battery charger 180?. A battery charger and protection circuits 272?, 182?, 162?. (SEEPROM), and 163 (SRAM), a digital IC 192?, an analog IC 190? and a capacitor array with a header connector 192?.

“The header connector 192 and capacitor array 192?” Include sixteen output decoupling caps, as well as their respective feed-through connectors to connect one side of each capacitor through the hermetically sealed case to a connector to which either the electrode array 110 or the lead extension 120 may be detached.

“The processor 160?” The processor 160 can be implemented with an application-specific integrated circuit (ASIC), field-programmable gate arrays (FPGA), or any other device that allows for full bidirectional communication and programming. The processor 160 may utilize an 8086 core (the 8086 is a commercially-available microprocessor available from, e.g., Intel), or a low power equivalent thereof, SRAM or other memory, two synchronous serial interface circuits, a serial EEPROM interface, and a ROM boot loader 735. The processor die 160? may further include an efficient clock oscillator circuit 164?, and (as noted earlier) mixer and modulator/demodulator circuitry implementing the QFAST RF telemetry method. The processor 160 also contains an analog-to-digital (A/D), circuit 734. monitor various system-level analog signals, impedances and regulator status. The processor 160? The processor 160? also includes the communication links to individual ASICs within the IPG 100?. Like all processors similar to it, the processor 160? operates according to a program stored in its memory circuits.

“The analog IC (AIC-190)” An ASIC may be used to function as the main integrated circuit. It will perform several functions necessary for the IPG 100’s functionality, such as providing power regulation, stimulus output and impedance measuring and monitoring. Electronic circuitry 194 Performs the impedance measurement function and monitoring function.”

“The analog IC 190?” It may also contain output current DAC circuitry 186 Configured to supply current to a load such as tissue. The output current DAC circuitry 186 The circuitry 186 may deliver as much as 20 mA in aggregate or up to 12.7mA on one channel in 0.1mA steps. It should be noted, however, that the output current DAC circuitry 186 According to one example embodiment, it may be possible to deliver any amount or combination of aggregate current and single-channel current.

“Regulators for IPG 100?” The voltage is supplied to the processor and digital sequencer. Are digital interface circuits residing on analog IC 190 A voltage is also supplied. The operating voltage for the output current DAC circuitry 186 is supplied by a programmable regulator. The IPG 100’s sealed case may contain the coupling capacitors and electrodes CX as well as any remaining circuitry from the analog IC 186?. The header connector 192? includes a feedthrough pin that allows for electrical connection between each of the coupling caps CN and their respective electrodes E1,E2,E3. . . Or E16.

“The digital IC (DigIC 191)? Functions as the primary interface between processor 160 and the digital IC (DigIC) 191. It acts as the primary interface between the processor 160? and the output current DAC Circuitry 186?. Its main function is to provide stimul information to the output power DAC Circuitry 186?. DigIC 191? The processor 160? then controls the stimuli levels and sequences and can be changed. The DigIC 191 is an example embodiment. The DigIC 191 is an example of a digital ASIC (digital application specific integrated circuit).

Now that we have a basic understanding of implantable stimulators, the focus shifts to the detailed description of battery protection and zero Volt recovery aspects. This disclosure is the main focus. While the disclosed techniques are most useful for implantable medical devices where the problem of zero Volt battery recovery is unique to that device, they can be applied to any device or system where zero-Volt recovery would be beneficial. Therefore, disclosure should not be considered as an example of a medical device implantable.

FIG. 7. Many of these components are very similar to the components in FIG. They are all labeled using the same element numbers, even though they may have slightly different functions. Protective and zero-Volt recovery circuitry 500 should be formed on an integrated circuit. However, it is possible to also include discrete components. Circuitry 500 can also be integrated with charge controller 684 and other integrated circuits of the IPG 100. The level of integration or combination of functions is merely a design decision.

“Briefly protection and zero-Volt recovery circuitry 500 consists in a preferred embodiment of two distinct charging paths. One is designated by node?Trickle?) For trickle changing and another (designated as node?Plus?) Normal charging. One diode 501 (a passive device that is not active gated, but which can be used for normal charging) intercedes between node Trickle, and the battery voltage,Vbat. If more than one diode was used, they would be connected serially, but this is not shown in FIG. 7 is for simplicity. A main switch 503, preferably a P channel MOS transistor, intervenes between node Plus & Vbat. This is controlled by a main switching control circuit 505, which can be found in FIG. 8. Load switch 504 acts as a bridge between node Plus (designated by node?Vdd?) and the load. It functions in a similar way to the load switch of FIG. 1. It is important to note that the battery 180 must be paired with the load by closing both switches 503 & 504, the main switch control 505 controlling one and the charge controller 684 controlling the other. A diode 502 can also be used to interconnect nodes Plus or Trickle. (In some other embodiments, diode502, like diode 51, could actually be a series of serially-connected diodes. FIG. 7 depicts a single diode to simplify things.

“Protection & zero-Volt Recovery Circuitry 500 basically supports & controls two operational modes: a discharging mode and a charging mode.”

The discharging mode can be implicated when the battery 180 and the load are coupled, e.g. during normal operation through main switch 503 or load switch 504. The circuit 500 can detect a short circuit in discharge mode. This is when the node Plus, Vdd to ground, and/or excessive current draws are detected by the circuit 500. These conditions indicate a problem with IPG 100. The main switch 503 is shut off by the main switch control circuit 505 in order to prevent the battery 180 being drained. It will stay off until the external charger208 turns it on. This point is discussed later.

“The charging mode can be further divided into two sub-modes, a trickle charging mode or a normal charging mode. These are similar to the ones discussed in FIGS. 1. and 2. 1. and 2. You will see that trickle charging uses current (Itrickle, approximately 10 mA) to charge the battery to 2.5V. When Vbat equals 2.5V the charge controller 684 switches on the normal charging mode. This allows the charge controller 684 to pass a greater current (Inormal) through node Plus to recharge the battery. The main switch 503 can be turned off when the battery 180 has been fully charged. This will isolate the battery 180 and the charge controller.

“As you may have noticed, the main switching 503 is controlled by the main switch control circuitry 505 and it is helpful to briefly explain how this circuitry 505 responds to the opening and closing of the main switching 503. FIG. FIG. 8.8 shows the various sensing circuits that are used to open or close the switch 503. This is not shown in FIG. 7 to clarify. These sensors are important for protection but can also be used to integrate the charge controller 684.

“Shown in FIG. “Shown in FIG. 8 are four sensors: A short circuit sensor510, a battery voltage detector 512, an excessive current sensor 516 and a main switch substrate reader 520. Each sensor takes as input the voltage at node Plus, Vbat, and the battery voltage. The reed switch 522 is preferably a separate component from any other integrated circuitry and can be used to disable the main switch 503 and terminate charging or discharging the battery 180 for any number of reasons.

The voltage at node Plus is monitored by the short circuit sensor 510. The voltage at node Plus is below an acceptable level. Sensor 510 indicates that there is a short circuit between Plus and ground. If load switch 504 is turned on, sensor 510 will direct the main switch control circuitry 505 to disable main switch 503. This will cause the battery 180 to drain to stop it from draining. To ensure safety, the short circuit sensor510 will direct the main switching control circuitry 505 (FIG. 1) to increase node Plus’ operating voltage to an acceptable level. The external charger 208’s ability to reset main switch 503 depends on the extent of the condition. “, which was the cause of the initial short circuit.”

The battery voltage sensor 512 measures the voltage 180 and informs the charge controller 684 about this value. This is so the charge controller can know when to switch between normal and trickle charging. The battery voltage sensor 512 can also be used to determine if Vbat is too high (e.g. greater than 4.2V) and, if so to activate self-discharge circuit 514 to lower it to the proper level. The battery voltage sensor512 instructs main switch control 505 that main switch 503 is closed if Vbat is within normal operating parameters (e.g. between 2.5V to 4.2V) and, otherwise, directs control 505 not to disable switch 503. You can trim the voltage levels of interest to battery voltage sensor512 (e.g. 2.5V, 4.2V) to adjust their values for process variations via multi-bit bus (not illustrated).

“Excessive current sensor 516 is similar to short circuit sensor 510 and can be used to disengage the battery 180 in high current draw conditions. The preferred embodiment of sensor 516 measures excessive current by measuring voltage drop across main switch 503, i.e. from node Plus and Vbat. The?on? Knowing the?on?

“The main switch substrate sensor 522 monitors the polarity (charge or discharge), across the main switching 503 and ties N-well 315 to the greater of Plus or Vbat in order to prevent current loss to substrate as described below.”

“The various sensors shown in FIG. 8. 8 can be built using standard reference circuits such as voltage dividers and differential amplifiers. These sensors circuits are well-known and can take many forms, as any skilled person in the art will see. Therefore, they are not further discussed.

“The main switch 503 uses a PMOS transistor that is located in an N well. FIG. 9. It is important to note that the source and drain areas of the main switch 503 are not symmetrically made as one skilled in art will appreciate. They are therefore arbitrarily named at FIG. Depending on whether the battery 180 has been charged or discharged, the voltages will vary. During normal charging, node Plus will be brought up by biasing from the charger 684, while Vbat will be brought down by the battery 180.

“Since these voltage polarities are different in the source and drain regions, the N well potential (node?Bias)? FIG. FIG. This reduces the potential for unwanted current draw to substrate.

Consider normal charging of a battery to illustrate the problem. The provision of current (i.e. voltage) at node Plus can be quite high upon charging. This is due to Vbat’s current charge. A parasitic PNP bipolar transistor (540) could be created if Vbat is connected to the N well at Bias. 9) could be turned on, with the result being that the current intended to trickle charge battery 180 would be routed through the substrate of main switch 503. This would cause the battery 180 to slow down or even stop charging. This problem cannot be fixed simply by connecting the N well (Bias), to node Plus. The parasitic effect at the other end of the source/drain switch 503 could occur during discharge. Vbat could be greater than Plus, which could cause the other terminal to turn on the parasitic, PNP bipolar transistor (542; FIG. 9), which causes current that is otherwise usable by the load to inadvertently drain to the substrate. This problem can be solved by biasing the N well (node Bias), to the higher source or drain nodes in main switch 503 via an polarity control circuit such as main switch substrate sensor520 (see FIG. 8). It is easy to design a polarity control circuit like this. There are many ways you can do it.

“With the overview of the protection circuitry 500 and zero-Volt recovery circuitry 500 now in hand, it is possible to focus on the circuit 500’s operation to charge and protect the battery 180 even when the voltage is zero.”

“In this regard, and in accordance with the previous note, see FIG. 7 shows that the trickle charging pathway (node Trickle, current Itrickle), is separate from the normal charging path. (node PLUS; current Inormal). The driving force behind the separation of these charging paths is zero-volt recovery. Separating the Trickle and Plus nodes can prevent the trickle charging current (Itrickle), from flowing into the Plus, and thus bipolar transistor parasitics at the main switch 503 cannot be implicated. The trickle current bypasses main switch 503, so any uncertainty about the status of the switch at low voltages can be avoided.

“However, current leakage from node Plus to substrate is a concern. One embodiment addresses this issue by keeping node Plus at a voltage that is suitable for trickle charging. In a preferred embodiment, node Plus is connected to Vbat during trickle charging. One embodiment achieves this by using diode(s). 502. Diode(s), 502, is used to match the voltage drop across diode (s) 501 during trickle charger to maintain the voltage at Plus equal to Vbat. This ensures that the trickle charge current doesn’t leak to the substrate via switch 503. This means that 502 could not be present and the voltage at Plus could drop to the battery. 503 could also leak to the substrate.

“Diodes 502 and 501 are shown in FIG. 7 diodes may be used. Two diodes are connected in series to form diodes 502 and 512. This is the preferred embodiment. It should also be noted that diodes 502 and 501 can be realized in series as transistors, where one of the source or drain is tied to the substrate (well). As such, ?diode? ?diode’ should be understood to include such structures and all other structures that can transmit one-way current.

“With Plus being held at Vbat during trickle charge, even though the N well is also biased to Vbat (FIG. Due to the zero-Volt difference in potential between the Well and Plus, 9) cannot be turned on. This biasing scheme also holds all junction nodes in main switch 503 to the same potential. Source=drain=N well=Vbat. This means that main switch 503 can not be used to carry current, regardless of what potential it has. It is possible to still turn the main switch 503 off if you wish. However, this is just like the N well. These functions could be performed by the same circuitry. This further ensures that the PMOS main switching 503 does not conduct during trickle charge.

“This is in contrast to FIG. 1. As discussed in the Background, low Vbat values, which had an effect on the ability to turn transistors 701, 702, and 701, are no longer relevant. Zero-Volt battery recovery is achieved through node Trickle. Even if various sensors such as the battery voltage sensor 512 (FIG. 8 cannot function reliably at lower Vbat values because trickle charging can occur regardless of what the sensors indicate to the main switching control 505, or how the main switch control 505 would bias the gate. Trickle charging is possible by the charge controller 684 providing a significant bias to node Trickle, which will allow the Plus node to draw current during trickle charging. This will enable the forward threshold of diode 505 to be overcome to generate the desired trickle current.

Once the battery 180 is trickled charged in the manner described above, Vbat will eventually rise to a level where normal charging can occur, e.g. at 2.5V. As an example, the battery voltage sensor 512 in FIG. 5 allows for monitoring Vbat to determine if there is a cross-over condition. 8 will begin functioning reliably after Vbat has been charged to a suitable high level (e.g. 2.0V). The gate voltage of main switch 503 during trickle charging was not relevant because of the voltage conditions in source, drain and well that prevented current flow. However, normal charging voltages have been sufficiently charged so that main switch control 505 (and other sensors reporting to it) can turn on switch 503 to allow current flow (Inormal). This current flows from the charge controller 684 through node Plus and eventually to the battery 180. Normal charging will cause the voltage at node Plus to be high. Therefore, diode 502 is reverse-biased. This will prevent the flow of current into node Trickle.

“In short, protection and zero Volt recovery circuitry 500 can both protect the battery and charge the battery 180, even in a zero-Volt state. Protection comes from the ability to isolate 180 the battery 180 from the load via load switch 504 as well as from the charge controller via main switches 503 and via diode 51 (which will prevent the battery from being discharged back to the charger 684). This protection does not prevent the circuitry 500 being charged. The battery can be charged via one of the two charging paths (Plus or Trickle) and the protection circuitry won’t prevent low-level charging at low voltages. After the battery is fully charged, the Plus path can be used to charge it through the protection circuitry (e.g. main switch 503) at nominal voltages. The battery and load are protected from adverse voltages and current conditions and can be fully recovered. This is particularly important when circuitry 500 is embedded in implantable medical devices like an IPG 100. Failure to recover a fully charged battery could result in the need for surgical removal.

“While the invention disclosed herein has been described using specific embodiments and their applications, many modifications and variations could still be made by those skilled in art without departing completely from the literal and comparable scope of the invention as set forth in its claims.”

Summary for “Battery protection for implantable medical devices”

“Implantable stimulation device generate and deliver electrical stimuli for the treatment of various biological disorders. These include pacemakers to treat cardiac arrhythmia and defibrillators that treat cardiac fibrillation. Cochlear stimulators are used to treat blindness. Muscle stimulators are used to produce coordinated limb movement. Spinal cord stimulators can be used to treat chronic pain. Cortical and deep brain stimulators can be used to treat motor and psychological disorders. Other neural stimulators may also be used to treat incontine, sleep a, shoulder sublaxation and to relieve symptoms such as apneapneapneapnea and to provide s to reduce hypnea and to help with a. Although the present invention could be applicable to all of these applications, the following description will focus on its use within a Spinal Cord Stimulation system (SCS), such as the one disclosed in U.S. Pat. No. No.

Spinal cord stimulation is an accepted clinical method to reduce pain in some populations. A typical SCS system includes an Implantable Pulse Generator, Radio-Frequency, or Radio-Frequency transmitter and receiver, electrodes and at least one lead. Optionally, there may be at least one lead extension. The electrodes are located at the distal end the electrode lead and are usually implanted along the spinal cord’s dura. The IPG or the RF transmitter generates electric pulses which are sent through the electrodes to nerve fibers in the spinal column. The individual electrode contacts (the “electrodes”) are what you see. To create an electrode array, the contacts (the?electrodes?) are placed in a particular arrangement. Each electrode is connected to its individual wires by connecting one or more electrode leads. The electrode leads exit the spine and attach to one or several electrode lead extensions. The electrode lead extensions are then tunneled around the patient’s torso to a subcutaneous pocket, where the IPG/RF transceiver can be implanted. Alternately, the electrode lead can be connected directly to the IPG/RF transceiver. U.S. Pat. provides examples of other SCS systems as well as other stimulation systems. Nos. Nos. Implantable pulse generators, which are active devices, require energy to operate, such as an implanted battery, or external power source.

An IPG requires electrical power to function. This should be obvious. This power can be supplied in a variety of ways. For example, an external charger may provide EM induction or a rechargeable, non-rechargeable battery. Other options include using an external charger or electromagnetic (EM) induction. These and other methods are further discussed in U.S. Pat. No. 6,553,263 (?the ‘263 patent? 6,553,263 (?the ‘263 patent) is incorporated by reference in its entirety. The most popular of these options is to use an IPG battery, either a lithium ion or a polymer battery. A rechargeable battery such as a lithium-ion or a polymer battery can usually provide enough power to run an IPG for several days without needing to be charged. EM induction can be used to recharge the IPG. An external charger sends EM fields to the IPG. The external charger can be used to charge the IPG’s battery when it is low.

FIG. 1 shows the basics of such an invention. 1. This is a description of the main contents of the ‘263 Patent. The system includes the relevant parts of the external charger 208 as well as IPG 100. A coil 279 within the charger 208 generates an EM field 290 that can be percutaneously transmitted through a patient’s flesh. 278 An external charger 208 can be powered using any known method, such as a battery or plugging into a wall socket. Another coil 270 meets the EM field 290 at the IPG 100 and in this coil 270 an AC voltage is induced. This AC voltage is then converted to a DC voltage at rectifier 682. It may also include a standard bridge circuit. The EM field 290 may also include data telemetry, but this information is not relevant to the present disclosure. The rectified DC voltage is then sent to the charge controller 684. This control generally operates to regulate the DC voltage, and produce a constant voltage or constant current output to recharge the battery 180. The battery voltage Vbat is a factor that determines the output of the charge regulator 684. This affects how aggressively the controller charges the battery 180. The charge controller 684 can also report the battery 180’s status to the external charger 208 via back-telemetry using coil270. However, this function is not relevant to this disclosure so it is not discussed further.

“The output from the charge controller 684 can be met by two switches 701,702, which prevent the battery 180’s over-charging and over-discharging. These transistors are N channel transistors. They will be?on?, as shown. These transistors are N-channel transistors, which can connect the output of the charge controller 684 to the battery 180 if their gates are biased. The battery protection circuit 686 controls these gates. It receives the voltage and current, Ibat, and Vbat as control signals. This will be discussed in more detail later. The battery protection circuit 686 will, for example, turn off the gate 701 of the overcharging transistor 701 if the battery 180 displays too high a voltage to prevent it from charging further. To further protect the battery against high current events, a fuse may be placed between the transistors 701, 702 or 180 (not shown). The battery 180 is connected to the IPG 100’s load switch 504, which connects it to the electrode stimulation circuitry. This circuitry powers the circuits that the battery 180 eventually powers. A load switch 504 is used to couple the battery 180 to these loads. This can protect the battery 180 from any adverse effects. The load switch 504 may be part of the charge controller 684. However, it is not necessary.

“The charging circuitry 684, as discussed in the ‘263 patent above, can charge the battery 180 in a variety of ways depending on the state of the battery voltage, Vbat. This selective charging of the battery 180, especially when it is lithium-ion-based, is advantageous for safe charging. This safe charging scheme charges the battery 180 at lower currents when Vbat is low. It charges higher currents at safer levels when Vbat is high.

Consider an embodiment where Vbat=4.2V is the nominal voltage for battery 180. The charge controller 684 will?trickle if Vbat=2.5V. The battery 180 can be charged with a low current, such as Ibat=10mA. Higher charging currents can be used as the battery charges and Vbat increases. The charge controller 684 may set a 50 mA charging current if Vbat is above 2.5V. The charge controller 684 can continue charging the battery 180 once the nominal voltage of 2.25V has been reached. This is done by providing a constant voltage on its output instead of a constant current. As the charging process continues, it will cause a gradual decline in the battery current. FIG. illustrates the relationship between Vbat (battery charging) and Ibat. 2. These voltage and current values are only examples. Other parameters may be appropriate depending on the system. You can also use more than one level of charging current, such as 10 mA or 25 mA respectively, in a stair-step fashion.

“The battery protection circuit 686 protects the battery against potential damage while charging. It disconnects the battery 684 from the charge controller 684. To prevent further charging, Vbat is disengaged by the battery protection circuit 686 if it exceeds a safe voltage (e.g., greater that 4.2V). To prevent the battery from being discharged, the over-discharge transistor 702 will be disabled if the battery voltage falls below a predetermined level or if Ibat is higher than a predetermined limit. Although two transistors 701 and 702 are controlled by the battery protection circuit 686, a single disable protection transistor may be used to disable the battery 180 when over-charging or over-discharging is done. To protect the components from adverse voltages or currents, the load switch 504 could be used to control it.

“While the charging circuitry and protection circuitry in FIG. Although FIG. 1’s charging and protection circuitry is compatible, it may not function properly at low battery voltages. The battery protection circuit 686, as described in the ‘263 Patent, is powered by Vbat. This means that when Vbat drops to zero Volts, the battery protection circuitry 686 might not work as intended. It is important to note that Vbat can be very low and the battery 180 needs to charge. The battery protection circuit 686 must be capable of turning transistors 701 & 702 on. Otherwise, the charging controller 684 won’t be able pass an Ibat charging current to the battery. The battery protection circuit 686 might have trouble generating enough voltage to turn the gates of N-channel transistors 701 or 702. However, Ibat can be low. The battery protection circuitry 686 must produce a voltage that is higher than Vgs for transistors. This refers to the potential difference between source and gate of the transistors. The battery protection circuitry must be capable of producing a gate voltage that exceeds Vt, given the source voltages at the transistors. The battery protection circuit 686 might not be able produce the necessary high gate voltage to turn transistors 701 or 702 on if Vbat falls below this threshold voltage.

“Should this happen, the battery 180 will not be charged even though Vbat may be low, and therefore the battery 180 will need to charge. FIG. Vbat below zero Volts, or very close to zero Volts, can cause 1 to fail. This would indicate that the IPG 100 may fail in the worst possible scenario. If implanted in a patient it could require surgical removal and replacement. This is unfortunate because IPGs can be implanted in patients who cannot be relied on to charge them properly. The risk of a dead battery is real.

“As such, it would be advantageous to have improved circuitry and techniques that protect and recover zero-Volt batteries from implantable medical devices. These solutions are available in this document.

The invention discloses circuitry that can be used to charge and protect a rechargeable battery from zero voltage. It is especially useful in implantable medical devices. There are two charging paths. One is for trickle charging the batteries at a low current, when the voltage is below a threshold. The second is for charging the battery at higher currents, when the voltage is higher than a certain threshold. The first trickle-charging pathway uses a passive diode to allow trickle charging, even though the battery voltage is not high enough for reliable gating. A second path charges the battery at higher currents when the voltage is higher so that the switch can be gated more consistently. The second diode is used between the two charging paths to prevent any leakage to substrates through the gateable switch. The switch couples the load to the battery, with a second switch preferably used for decoupling.

The following description is the best way to carry out the invention. This description should not be taken as a limitation of the invention’s principles. It is important to refer to the claims and equivalents when determining the scope of the invention.

“Before we discuss the battery protection and zero Volt recovery aspects, which are the main focus of this disclosure. The circuitry, structure and function of an implantable stimulation device in which the disclosed technique can be used are set forth for completeness with regard to FIGS. 3-6. The implantable stimulator device disclosed may include an implantable pulse generator, or similar electrical stimulator/or sensor that can be used in a variety of stimulation systems. The following description focuses on the use of the invention in a spinal cord stimulation system (SCS). It is important to understand that the invention does not limit itself. The invention can be used with any type or implantable electrical circuitry that would benefit from enhanced battery protection and zero Volt recovery techniques. The present invention can be used in a pacemaker or implantable pump. It may also be used in a cochlear or retinal stimulator. A stimulator that produces coordinated limb movement, cortical or deep-brain stimulator or any other stimulator designed to treat urinary incontinence or sleep apnea. The technique is also suitable for use in non-medical devices and/or systems that do not require battery recovery or protection.

“Turning first, FIG. 3. A block diagram shows the components of an exemplary SCS-system in which the invention can be used. These components can be divided into three categories: surgical components 30, external components 20, or implantable components 10. FIG. FIG. 3 shows the implantable components 10. They include an implantable pulse generator 100, an electrode array 110 and, as needed, a lead extension 120. The extension 120 can be used to connect the electrode array 110 and the IPG 100. The IPG 100 is an example embodiment. This will be described in greater detail below with reference to FIG. 5 or 6, may comprise a rechargeable, multi-channel, telemetry-controlled, pulse generator housed in a rounded high-resistivity titanium alloy case to reduce eddy current heating during the inductive charging process. The IPG 100 can provide electrical stimulation using a variety of electrodes. E1 through E16 are included in the electrode array 110.

“In this context, the IPG 100 could include stimulating electrical circuitry (or?stimulating electronics). The IPG 100 may include a power source (e.g., a rechargeable batteries) and a telemetry device, which are particularly relevant for embodiments of the invention. The IPG 100 is typically placed in a pocket surgically made in the abdomen or at the top of your buttocks. You can also place it in other parts of your body. The IPG 100 is attached to the lead system. This includes the lead extension 120 and the electrode array 110. For example, the lead extension 120 may be tunneled to the spinal column. After the trial stimulation period has ended, the lead system 110 or lead extension 120 will be permanently implanted. The IPG 100, on the other hand, can be replaced if it fails.

“As seen best in FIG. FIG. 4 and FIG. 3. The electrode array 110 and associated lead system interface typically with the implantable pulse generator 100 (IPG), 100 via the lead extension 120. An external trial stimulator 140 may be connected to the electrode array 110 via a percutaneous extension 132 or external cable 134. The IPG 100’s pulse generation circuitry is similar to the external trial stimulator 140. It is used for a trial period of 7-10 days after the electrode array is implanted.

“Still with reference FIGS. “Still with reference to FIGS. This control allows the IPG 100’s turn on and off. It also allows stimulation parameters (e.g. pulse amplitude, width, rate) to be set by patients or clinicians within prescribed limits. Through another link 205? (e.g. an infra-red link), the HHP 202 can be connected to the external trial stimulator 140. An external programmer (CP), 204 is recommended for the programming of the IPG 100. 3.) may also be handheld and may be connected to the IPG 100 via link 201a or indirectly via the HHP202. A non-invasively connected external charger 208 with the IPG 100 via link 290, e.g. an inductive link allows energy stored or made available to the charger208 to be coupled into a rechargeable battery 180 contained within the IPG 100.

“Turning next, FIG. 5 shows a block diagram that illustrates the main components in one embodiment of an implantable pace generator (IPG 100). Other embodiments of this invention could also be used. FIG. FIG. 5 shows the IPG, which includes a microcontroller 160 that is connected to 162 of the memory circuitry. The?C 160 is typically composed of a microprocessor with associated logic circuitry. These circuits, along with control logic circuits 166, 168 and an oscillator/clock circuit 164, create the necessary control signals and status signals that allow the?C 160 control the IPG’s operation in accordance to a chosen operating program and stimulation parameters. (A ?microcontroller? as used herein should be understood as any integrated device capable of processing signals in the IPG, including traditional microcontrollers, microprocessors, or other signal processors, including those that are application-specific, such as ASIC chips).”

“The operating program, as well as the stimulation parameters, are telemetered from the IPG 100 to antenna 250. They are then processed via RF-telemetry circuitry172 and stored in the memory 162. The RF-telemetry circuitry 172 modifies the signal it receives via the HHP 202 and CP 204 in order to recover the operating programme and/or stimulation parameters. The antenna 250 receives signals and passes them through the transmit/receive button 254 to amplifiers or filters 258. The received signals are then demodulated (262), using Frequency Shift Keying demodulation, and sent to the microcontroller 160 for further processing or storage. The RF-telemetry circuitry 172 transmits information to the HHP 202 and CP 204. This allows them to update their status in some way. The microcontroller 160 then sends the relevant data to the transmission drivers 256. There the carrier is modulated with the data and amplified to transmit. The transmit/receive button 254 would be used to communicate with the transmission driver 256. This in turn drives the data to antenna 250 for broadcast.

“The microcontroller 160 can be further connected to the monitoring circuits 173 via bus 173. Monitoring circuits 174 monitor various points 175 in the IPG 100. They include power supply voltages, current values and temperature. . . EN and similar. Informational data that is sensed by the monitoring circuit 173 may be sent to an external location (e.g., non-implanted) via telemetry circuitry 172 via coil 170.

The operating power of the IPG 100 can be obtained from a rechargeable source 180. This could include a lithium-ion, lithium-ion polymer, or both. The 180-volt rechargeable battery provides unregulated voltage for power circuits 182. The power circuits 182 generate various voltages 184. Some of these are regulated, others not, depending on the requirements of the IPG 100. Preferably, the battery 180 can be charged using an electromagnetic field generated by an external portable charger (FIGS. As noted, 1, 3, The IPG 100 is placed close to the charger 208, e.g., about 100 cm away. An electromagnetic field from the portable charger induces a current in the charging coil 270 (even though the patient’s skin). As explained in the Background, this current is rectified and controlled to charge the battery 180. The charging circuitry also includes charging telemetry circuitry 272, used by the IPG 100 to notify the portable charger 208 of full battery status and when it can be turned off.

“In an exemplary embodiment, any N electrode may be assigned to up k possible groups/?channels. In one preferred embodiment, k can equal four. Any of the N electrodes may operate in any of the k channels, or be integrated into, them. The channel indicates which electrodes will synchronously supply or sink current in order to stimulate the tissue. The HHP 202 can control the amplitudes and polarities for electrodes in a channel. The CP 204’s external programming software allows you to program parameters such as electrode polarity, amplitude and pulse rate for each channel.

The N programmable electrodes have the ability to be programmed to either have a positive (sourcing current), a negative (sinking curent), or off (no present) polarity in any one of the k channels. Each of the N electrodes may operate in either a bipolar or multipolar mode. For example, two or more electrode contacts can be grouped together to source/sink the current simultaneously. Each of the N electrodes may also operate in a monopolar mode, where the electrode contacts associated to a channel can be configured as cathodes (negative) and the case electrode (i.e. the IPG case), is configured as an anide (positive).

“Further the amplitude or source of the current pulse that is sunk or sourced to an electrode contact can be programmed to one or more discrete current levels. For example, between 0 and?10mA in steps of 0.01 mA. The pulse width of current pulses can be adjusted in convenient increments. For example, it is possible to adjust the pulse width from 0 to 1 microseconds (ms), in increments of 10 microseconds. The pulse rate can be adjusted within acceptable limits. For example, it could be set to 0 to 1000 Hz. Other features that can be programmed include slow start/end ramping and burst stimulation cycling (on/off for X time) as well as open or closed loop sensing mode.

The stimulation pulses generated using the IPG 100 could be charged balanced. The stimulation pulses generated by the IPG 100 may be charged balanced. This means that the stimulus pulse’s positive charge is countered with a negative charge. Coupler capacitors Cx can achieve the desired charge balance by providing a passive discharge capacitor that produces the required charge-balancing condition. To achieve the desired charge balance condition, you can also use active biphasic and multi-phasic pulses that have balanced positive and negative phases.

The IPG 100 can control the currents at each of the N electrodes. The control of the digital-to-analog current circuitry 186 with the microcontroller 160 and the timer logic 168 allows each electrode contact, together with the control logic 166, and logic 168 to pair or group other electrode contacts to adjust the polarity, amplitude and rate at which the current stimulus pulses are delivered.

“As shown at FIG. 5 circuitry in the IPG 100 can be implemented on one application-specific integrated circuit (ASIC). 190. The IPG 100 is compact and can be easily housed in a hermetically sealed case. N feedthroughs may be included in the IPG 100 to allow individual electrical contact from the sealed case. The N electrodes are located outside the case.

The IPG 100 can be used in surgery, as described earlier. It may be placed in the abdomen, or at the top of your buttocks. The lead system is meant to last forever, but the IPG 100 can be removed and replaced if it fails.

The IPG 100’s telemetry features allow for the monitoring of the IPG 100’s status. The HHP 202 or CP 204 can initiate a programming session using the IPG 100. This allows the external programmer to calculate the expected time of recharge. Back-telemetry confirms that any changes to the current stimulus parameters have been received and are implemented within the implant system. All programmable settings within the implant system 10, which are available for interrogation by an external programmer, can be uploaded to one or several external programmers.

“Turning next FIG. 6. A hybrid block diagram of an alternate embodiment of the IPG 100? Illustration of the IPG 100? What is the IPG 100? The IPG 100 can house both digital and analog dies or integrated circuits (ICs), and may be contained in one hermetically sealed rounded case with a maximum diameter of approximately 45 mm and thickness of around 10 mm. Many of the circuits in the IPG 100 are identical or similar to the ones shown in FIG. Many of the circuits in the IPG 100 are similar or identical to those shown in FIG. 5. IPG 100? Includes a processor chip 160?, and an RF telemetry circuit 172? (typically made with discrete components), a processor die 160?, an RF telemetry circuit 172?, and a battery charger 180?. A battery charger and protection circuits 272?, 182?, 162?. (SEEPROM), and 163 (SRAM), a digital IC 192?, an analog IC 190? and a capacitor array with a header connector 192?.

“The header connector 192 and capacitor array 192?” Include sixteen output decoupling caps, as well as their respective feed-through connectors to connect one side of each capacitor through the hermetically sealed case to a connector to which either the electrode array 110 or the lead extension 120 may be detached.

“The processor 160?” The processor 160 can be implemented with an application-specific integrated circuit (ASIC), field-programmable gate arrays (FPGA), or any other device that allows for full bidirectional communication and programming. The processor 160 may utilize an 8086 core (the 8086 is a commercially-available microprocessor available from, e.g., Intel), or a low power equivalent thereof, SRAM or other memory, two synchronous serial interface circuits, a serial EEPROM interface, and a ROM boot loader 735. The processor die 160? may further include an efficient clock oscillator circuit 164?, and (as noted earlier) mixer and modulator/demodulator circuitry implementing the QFAST RF telemetry method. The processor 160 also contains an analog-to-digital (A/D), circuit 734. monitor various system-level analog signals, impedances and regulator status. The processor 160? The processor 160? also includes the communication links to individual ASICs within the IPG 100?. Like all processors similar to it, the processor 160? operates according to a program stored in its memory circuits.

“The analog IC (AIC-190)” An ASIC may be used to function as the main integrated circuit. It will perform several functions necessary for the IPG 100’s functionality, such as providing power regulation, stimulus output and impedance measuring and monitoring. Electronic circuitry 194 Performs the impedance measurement function and monitoring function.”

“The analog IC 190?” It may also contain output current DAC circuitry 186 Configured to supply current to a load such as tissue. The output current DAC circuitry 186 The circuitry 186 may deliver as much as 20 mA in aggregate or up to 12.7mA on one channel in 0.1mA steps. It should be noted, however, that the output current DAC circuitry 186 According to one example embodiment, it may be possible to deliver any amount or combination of aggregate current and single-channel current.

“Regulators for IPG 100?” The voltage is supplied to the processor and digital sequencer. Are digital interface circuits residing on analog IC 190 A voltage is also supplied. The operating voltage for the output current DAC circuitry 186 is supplied by a programmable regulator. The IPG 100’s sealed case may contain the coupling capacitors and electrodes CX as well as any remaining circuitry from the analog IC 186?. The header connector 192? includes a feedthrough pin that allows for electrical connection between each of the coupling caps CN and their respective electrodes E1,E2,E3. . . Or E16.

“The digital IC (DigIC 191)? Functions as the primary interface between processor 160 and the digital IC (DigIC) 191. It acts as the primary interface between the processor 160? and the output current DAC Circuitry 186?. Its main function is to provide stimul information to the output power DAC Circuitry 186?. DigIC 191? The processor 160? then controls the stimuli levels and sequences and can be changed. The DigIC 191 is an example embodiment. The DigIC 191 is an example of a digital ASIC (digital application specific integrated circuit).

Now that we have a basic understanding of implantable stimulators, the focus shifts to the detailed description of battery protection and zero Volt recovery aspects. This disclosure is the main focus. While the disclosed techniques are most useful for implantable medical devices where the problem of zero Volt battery recovery is unique to that device, they can be applied to any device or system where zero-Volt recovery would be beneficial. Therefore, disclosure should not be considered as an example of a medical device implantable.

FIG. 7. Many of these components are very similar to the components in FIG. They are all labeled using the same element numbers, even though they may have slightly different functions. Protective and zero-Volt recovery circuitry 500 should be formed on an integrated circuit. However, it is possible to also include discrete components. Circuitry 500 can also be integrated with charge controller 684 and other integrated circuits of the IPG 100. The level of integration or combination of functions is merely a design decision.

“Briefly protection and zero-Volt recovery circuitry 500 consists in a preferred embodiment of two distinct charging paths. One is designated by node?Trickle?) For trickle changing and another (designated as node?Plus?) Normal charging. One diode 501 (a passive device that is not active gated, but which can be used for normal charging) intercedes between node Trickle, and the battery voltage,Vbat. If more than one diode was used, they would be connected serially, but this is not shown in FIG. 7 is for simplicity. A main switch 503, preferably a P channel MOS transistor, intervenes between node Plus & Vbat. This is controlled by a main switching control circuit 505, which can be found in FIG. 8. Load switch 504 acts as a bridge between node Plus (designated by node?Vdd?) and the load. It functions in a similar way to the load switch of FIG. 1. It is important to note that the battery 180 must be paired with the load by closing both switches 503 & 504, the main switch control 505 controlling one and the charge controller 684 controlling the other. A diode 502 can also be used to interconnect nodes Plus or Trickle. (In some other embodiments, diode502, like diode 51, could actually be a series of serially-connected diodes. FIG. 7 depicts a single diode to simplify things.

“Protection & zero-Volt Recovery Circuitry 500 basically supports & controls two operational modes: a discharging mode and a charging mode.”

The discharging mode can be implicated when the battery 180 and the load are coupled, e.g. during normal operation through main switch 503 or load switch 504. The circuit 500 can detect a short circuit in discharge mode. This is when the node Plus, Vdd to ground, and/or excessive current draws are detected by the circuit 500. These conditions indicate a problem with IPG 100. The main switch 503 is shut off by the main switch control circuit 505 in order to prevent the battery 180 being drained. It will stay off until the external charger208 turns it on. This point is discussed later.

“The charging mode can be further divided into two sub-modes, a trickle charging mode or a normal charging mode. These are similar to the ones discussed in FIGS. 1. and 2. 1. and 2. You will see that trickle charging uses current (Itrickle, approximately 10 mA) to charge the battery to 2.5V. When Vbat equals 2.5V the charge controller 684 switches on the normal charging mode. This allows the charge controller 684 to pass a greater current (Inormal) through node Plus to recharge the battery. The main switch 503 can be turned off when the battery 180 has been fully charged. This will isolate the battery 180 and the charge controller.

“As you may have noticed, the main switching 503 is controlled by the main switch control circuitry 505 and it is helpful to briefly explain how this circuitry 505 responds to the opening and closing of the main switching 503. FIG. FIG. 8.8 shows the various sensing circuits that are used to open or close the switch 503. This is not shown in FIG. 7 to clarify. These sensors are important for protection but can also be used to integrate the charge controller 684.

“Shown in FIG. “Shown in FIG. 8 are four sensors: A short circuit sensor510, a battery voltage detector 512, an excessive current sensor 516 and a main switch substrate reader 520. Each sensor takes as input the voltage at node Plus, Vbat, and the battery voltage. The reed switch 522 is preferably a separate component from any other integrated circuitry and can be used to disable the main switch 503 and terminate charging or discharging the battery 180 for any number of reasons.

The voltage at node Plus is monitored by the short circuit sensor 510. The voltage at node Plus is below an acceptable level. Sensor 510 indicates that there is a short circuit between Plus and ground. If load switch 504 is turned on, sensor 510 will direct the main switch control circuitry 505 to disable main switch 503. This will cause the battery 180 to drain to stop it from draining. To ensure safety, the short circuit sensor510 will direct the main switching control circuitry 505 (FIG. 1) to increase node Plus’ operating voltage to an acceptable level. The external charger 208’s ability to reset main switch 503 depends on the extent of the condition. “, which was the cause of the initial short circuit.”

The battery voltage sensor 512 measures the voltage 180 and informs the charge controller 684 about this value. This is so the charge controller can know when to switch between normal and trickle charging. The battery voltage sensor 512 can also be used to determine if Vbat is too high (e.g. greater than 4.2V) and, if so to activate self-discharge circuit 514 to lower it to the proper level. The battery voltage sensor512 instructs main switch control 505 that main switch 503 is closed if Vbat is within normal operating parameters (e.g. between 2.5V to 4.2V) and, otherwise, directs control 505 not to disable switch 503. You can trim the voltage levels of interest to battery voltage sensor512 (e.g. 2.5V, 4.2V) to adjust their values for process variations via multi-bit bus (not illustrated).

“Excessive current sensor 516 is similar to short circuit sensor 510 and can be used to disengage the battery 180 in high current draw conditions. The preferred embodiment of sensor 516 measures excessive current by measuring voltage drop across main switch 503, i.e. from node Plus and Vbat. The?on? Knowing the?on?

“The main switch substrate sensor 522 monitors the polarity (charge or discharge), across the main switching 503 and ties N-well 315 to the greater of Plus or Vbat in order to prevent current loss to substrate as described below.”

“The various sensors shown in FIG. 8. 8 can be built using standard reference circuits such as voltage dividers and differential amplifiers. These sensors circuits are well-known and can take many forms, as any skilled person in the art will see. Therefore, they are not further discussed.

“The main switch 503 uses a PMOS transistor that is located in an N well. FIG. 9. It is important to note that the source and drain areas of the main switch 503 are not symmetrically made as one skilled in art will appreciate. They are therefore arbitrarily named at FIG. Depending on whether the battery 180 has been charged or discharged, the voltages will vary. During normal charging, node Plus will be brought up by biasing from the charger 684, while Vbat will be brought down by the battery 180.

“Since these voltage polarities are different in the source and drain regions, the N well potential (node?Bias)? FIG. FIG. This reduces the potential for unwanted current draw to substrate.

Consider normal charging of a battery to illustrate the problem. The provision of current (i.e. voltage) at node Plus can be quite high upon charging. This is due to Vbat’s current charge. A parasitic PNP bipolar transistor (540) could be created if Vbat is connected to the N well at Bias. 9) could be turned on, with the result being that the current intended to trickle charge battery 180 would be routed through the substrate of main switch 503. This would cause the battery 180 to slow down or even stop charging. This problem cannot be fixed simply by connecting the N well (Bias), to node Plus. The parasitic effect at the other end of the source/drain switch 503 could occur during discharge. Vbat could be greater than Plus, which could cause the other terminal to turn on the parasitic, PNP bipolar transistor (542; FIG. 9), which causes current that is otherwise usable by the load to inadvertently drain to the substrate. This problem can be solved by biasing the N well (node Bias), to the higher source or drain nodes in main switch 503 via an polarity control circuit such as main switch substrate sensor520 (see FIG. 8). It is easy to design a polarity control circuit like this. There are many ways you can do it.

“With the overview of the protection circuitry 500 and zero-Volt recovery circuitry 500 now in hand, it is possible to focus on the circuit 500’s operation to charge and protect the battery 180 even when the voltage is zero.”

“In this regard, and in accordance with the previous note, see FIG. 7 shows that the trickle charging pathway (node Trickle, current Itrickle), is separate from the normal charging path. (node PLUS; current Inormal). The driving force behind the separation of these charging paths is zero-volt recovery. Separating the Trickle and Plus nodes can prevent the trickle charging current (Itrickle), from flowing into the Plus, and thus bipolar transistor parasitics at the main switch 503 cannot be implicated. The trickle current bypasses main switch 503, so any uncertainty about the status of the switch at low voltages can be avoided.

“However, current leakage from node Plus to substrate is a concern. One embodiment addresses this issue by keeping node Plus at a voltage that is suitable for trickle charging. In a preferred embodiment, node Plus is connected to Vbat during trickle charging. One embodiment achieves this by using diode(s). 502. Diode(s), 502, is used to match the voltage drop across diode (s) 501 during trickle charger to maintain the voltage at Plus equal to Vbat. This ensures that the trickle charge current doesn’t leak to the substrate via switch 503. This means that 502 could not be present and the voltage at Plus could drop to the battery. 503 could also leak to the substrate.

“Diodes 502 and 501 are shown in FIG. 7 diodes may be used. Two diodes are connected in series to form diodes 502 and 512. This is the preferred embodiment. It should also be noted that diodes 502 and 501 can be realized in series as transistors, where one of the source or drain is tied to the substrate (well). As such, ?diode? ?diode’ should be understood to include such structures and all other structures that can transmit one-way current.

“With Plus being held at Vbat during trickle charge, even though the N well is also biased to Vbat (FIG. Due to the zero-Volt difference in potential between the Well and Plus, 9) cannot be turned on. This biasing scheme also holds all junction nodes in main switch 503 to the same potential. Source=drain=N well=Vbat. This means that main switch 503 can not be used to carry current, regardless of what potential it has. It is possible to still turn the main switch 503 off if you wish. However, this is just like the N well. These functions could be performed by the same circuitry. This further ensures that the PMOS main switching 503 does not conduct during trickle charge.

“This is in contrast to FIG. 1. As discussed in the Background, low Vbat values, which had an effect on the ability to turn transistors 701, 702, and 701, are no longer relevant. Zero-Volt battery recovery is achieved through node Trickle. Even if various sensors such as the battery voltage sensor 512 (FIG. 8 cannot function reliably at lower Vbat values because trickle charging can occur regardless of what the sensors indicate to the main switching control 505, or how the main switch control 505 would bias the gate. Trickle charging is possible by the charge controller 684 providing a significant bias to node Trickle, which will allow the Plus node to draw current during trickle charging. This will enable the forward threshold of diode 505 to be overcome to generate the desired trickle current.

Once the battery 180 is trickled charged in the manner described above, Vbat will eventually rise to a level where normal charging can occur, e.g. at 2.5V. As an example, the battery voltage sensor 512 in FIG. 5 allows for monitoring Vbat to determine if there is a cross-over condition. 8 will begin functioning reliably after Vbat has been charged to a suitable high level (e.g. 2.0V). The gate voltage of main switch 503 during trickle charging was not relevant because of the voltage conditions in source, drain and well that prevented current flow. However, normal charging voltages have been sufficiently charged so that main switch control 505 (and other sensors reporting to it) can turn on switch 503 to allow current flow (Inormal). This current flows from the charge controller 684 through node Plus and eventually to the battery 180. Normal charging will cause the voltage at node Plus to be high. Therefore, diode 502 is reverse-biased. This will prevent the flow of current into node Trickle.

“In short, protection and zero Volt recovery circuitry 500 can both protect the battery and charge the battery 180, even in a zero-Volt state. Protection comes from the ability to isolate 180 the battery 180 from the load via load switch 504 as well as from the charge controller via main switches 503 and via diode 51 (which will prevent the battery from being discharged back to the charger 684). This protection does not prevent the circuitry 500 being charged. The battery can be charged via one of the two charging paths (Plus or Trickle) and the protection circuitry won’t prevent low-level charging at low voltages. After the battery is fully charged, the Plus path can be used to charge it through the protection circuitry (e.g. main switch 503) at nominal voltages. The battery and load are protected from adverse voltages and current conditions and can be fully recovered. This is particularly important when circuitry 500 is embedded in implantable medical devices like an IPG 100. Failure to recover a fully charged battery could result in the need for surgical removal.

“While the invention disclosed herein has been described using specific embodiments and their applications, many modifications and variations could still be made by those skilled in art without departing completely from the literal and comparable scope of the invention as set forth in its claims.”

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What is a software medical device?

The FDA can refer to software functions that include ” Software As a Medical Device” and “Software in a Medical Device(SiMD)”, which are software functions that are integral to (embedded in a) a medical device.

Section 201(h),?21 U.S.C. 321(h),(1) defines a medical device to be?an apparatus, implements, machine, contrivances, implant, in vitro regulator, or other similar or related articles, as well as a component or accessory. . . (b) is intended for diagnosis or treatment of disease or other conditions in humans or animals. (c) Is intended to alter the structure or function of human bodies or animals. To be considered a medical device, and thus subject to FDA regulation, the software must meet at least one of these criteria:

• It must be used in diagnosing and treating patients.
• It must not be designed to alter the structure or function of the body.

If your software is designed to be used by healthcare professionals to diagnose, treat, or manage patient information in hospitals, the FDA will likely consider such software to be medical devices that are subject to regulatory review.

Is Your Software a Medical Device?

FDA’s current oversight, which puts more emphasis on the functionality of the software than the platform, will ensure that FDA does not regulate medical devices with functionality that could be dangerous to patient safety. Examples of Device Software and Mobile Medical Apps FDA is focused on

• Software functions that aid patients with diagnosed mental disorders (e.g., depression, anxiety, and post-traumatic stress disorder (PTSD), etc.) by providing “Skill of the Day”, a behavioral technique, or audio messages, that the user can access when they are experiencing anxiety.
• Software functions that offer periodic reminders, motivational guidance, and educational information to patients who are recovering from addiction or smokers trying to quit;
• Software functions that use GPS location data to alert asthmatics when they are near high-risk locations (substance abusers), or to alert them of potential environmental conditions that could cause symptoms.
• Software that uses video and games to encourage patients to exercise at home.
• Software functions that prompt users to choose which herb or drug they wish to take simultaneously. They also provide information about interactions and give a summary of the type of interaction reported.
• Software functions that take into account patient characteristics, such as gender, age, and risk factors, to offer patient-specific counseling, screening, and prevention recommendations from established and well-respected authorities.
• Software functions that use a list of common symptoms and signs to give advice about when to see a doctor and what to do next.
• Software functions that help users to navigate through a questionnaire about symptoms and to make a recommendation on the best type of healthcare facility for them.
• These mobile apps allow users to make pre-specified nurse calls or emergency calls using broadband or cell phone technology.
• Apps that allow patients or caregivers to send emergency notifications to first responders via mobile phones
• Software that tracks medications and provides user-configured reminders to improve medication adherence.
• Software functions that give patients access to their health information. This includes historical trending and comparisons of vital signs (e.g. body temperature, heart rate or blood pressure).
• Software functions that display trends in personal healthcare incidents (e.g. hospitalization rates or alert notification rate)
• Software functions allow users to electronically or manually enter blood pressure data, and to share it via e-mail, track it and trend it, and upload it to an electronic or personal health record.
• Apps that offer mobile apps for tracking and reminders about oral health or tools to track users suffering from gum disease.
• Apps that offer mobile guidance and tools for prediabetes patients;
• Apps that allow users to display images and other messages on their mobile devices, which can be used by substance abusers who want to quit addictive behaviors.
• Software functions that provide drug interaction and safety information (side effects and drug interactions, active ingredient, active ingredient) in a report based upon demographic data (age and gender), current diagnosis (current medications), and clinical information (current treatment).
• Software functions that allow the surgeon to determine the best intraocular lens powers for the patient and the axis of implantation. This information is based on the surgeon’s inputs (e.g., expected surgically induced astigmatism and patient’s axial length, preoperative corneal astigmatism etc.).
• Software, usually mobile apps, converts a mobile platform into a regulated medical device.
• Software that connects with a mobile platform via a sensor or lead to measure and display electrical signals from the heart (electrocardiograph; ECG).
• Software that attaches a sensor or other tools to the mobile platform to view, record and analyze eye movements to diagnose balance disorders
• Software that collects information about potential donors and transmits it to a blood collection facility. This software determines if a donor is eligible to collect blood or other components.
• Software that connects to an existing device type in order to control its operation, function, or energy source.
• Software that alters or disables the functions of an infusion pump
• Software that controls the inflation or deflation of a blood pressure cuff
• Software that calibrates hearing aids and assesses sound intensity characteristics and electroacoustic frequency of hearing aids.

What does it mean if your software/SaaS is classified as a medical device?

SaaS founders need to be aware of the compliance risks that medical devices pose. Data breaches are one of the biggest risks. Medical devices often contain sensitive patient data, which is why they are subject to strict regulations. This data could lead to devastating consequences if it were to become unprotected. SaaS companies who develop medical devices need to take extra precautions to ensure their products are safe.

So who needs to apply for FDA clearance? The FDA defines a ?mobile medical app manufacturer? is any person or entity who initiates specifications, designs, labels, or creates a software system or application for a regulated medical device in whole or from multiple software components. This term does not include persons who exclusively distribute mobile medical apps without engaging in manufacturing functions; examples of such distributors may include the app stores.

Software As Medical Device Patenting Considerations

The good news is that investors like medical device companies which have double exclusivity obtained through FDA and US Patent and Trademark Office (USPTO) approvals. As such, the exit point for many medical device companies is an acquisition by cash rich medical public companies. This approach enables medical devices to skip the large and risky go-to-market (GTM) spend and work required to put products in the hands of consumers.

Now that we have discussed the FDA review process, we will discuss IP issues for software medical device companies. Typically, IP includes Patents, Trademarks, Copyrights, and Trade secrets. All of these topics matter and should be considered carefully. However, we will concentrate on patents to demonstrate how careless drafting and lack of planning can lead to problems, namely unplanned disclosures of your design that can then be used as prior art against your patent application.

In general, you should file patent application(s) as soon as practicable to get the earliest priority dates. This will help you when you talk to investors, FDA consultants, prototyping firms, and government agencies, among others. Compliance or other documents filed with any government agency may be considered disclosure to third parties and could make the document public. In general, disclosures to third parties or public availability of an invention trigger a one year statutory bar during which you must file your patent application. Failure to file your application within the required time frame could result in you losing your right to protect your invention.

The information from your FDA application may find its way into FDA databases, including DeNovo, PMA and 510k databases and FDA summaries of orders, decisions, and other documents on products and devices currently being evaluated by the FDA. Your detailed information may be gleaned from Freedom of Information Act requests on your application. This risk mandates that you patent your invention quickly.

When you patent your medical device invention, have a global picture of FDA regulatory framework when you draft your patent application. Be mindful of whether your software/SaaS application discusses the diagnosing and treating patients or affecting the structure or function of the body and add language to indicate that such description in the patent application relates to only one embodiment and not to other embodiments. That way you have flexibility in subsequent discussions with the FDA if you want to avoid classification of your software/SaaS/software as a medical device. In this way, if you wish to avoid FDA registration and oversight, you have the flexibility to do so.

An experienced attorney can assist you in navigating the regulatory landscape and ensure that you comply with all applicable laws. This area of law is complex and constantly changing. It is important that you seek legal advice if you have any questions about whether or not your software should be registered with FDA.

Patent PC is an intellectual property and business law firm that was built to speed startups. We have internally developed AI tools to assist our patent workflow and to guide us in navigating through government agencies. Our business and patent lawyers are experienced in software, SaaS, and medical device technology. For a flat fee, we offer legal services to startups, businesses, and intellectual property. Our lawyers do not have to track time as there is no hourly billing and no charges for calls or emails. We just focus on getting you the best legal work for your needs.

Our expertise ranges from advising established businesses on regulatory and intellectual property issues to helping startups in their early years. Our lawyers are familiar with helping entrepreneurs and fast-moving companies in need of legal advice regarding company formation, liability, equity issuing, venture financing, IP asset security, infringement resolution, litigation, and equity issuance. For a confidential consultation, contact us at 800-234-3032 or make an appointment here.