Wireless power transfer circuit for a rechargeable implantable pulse generator

Patent metadata

Field	Value
Publication number	US-12508435-B2
Application number	US-202218078244-A
Country	US
Kind code	B2
Filing date	Dec 9, 2022
Priority date	Apr 15, 2019
Publication date	Dec 30, 2025
Grant date	Dec 30, 2025

Abstract

A charging energy control system includes an implantable medical device (IMD) and an external charger for effectuating wireless power transfer. The IMD receives charging energy to recharge a battery during an ON period and rejects the charging energy during an OFF period. A series switch is disposed between the IMD's coil and rectifier circuitry that is controlled by voltage regulation circuitry operative to generate a clamp control signal configured to detune the coil in the OFF state.

First claim

What is claimed is:

1 . A method of charging an implantable medical device (IMD) implanted within a patient for providing stimulation therapy, the method comprising:
positioning an external charger proximate to the patient for effectuating a near field coupling relationship with the IMD, wherein the external charger includes a primary coil and the IMD includes a secondary coil; selecting one or more charging parameters for driving the primary coil to generate radio frequency (RF) power at a particular frequency, the RF power inducing a voltage in the secondary coil of the IMD; converting the induced voltage to a charging voltage by a bridge rectifier of the IMD; detecting clamping of the secondary coil due to at least one of: (i) detuning the secondary coil caused by opening a series switch disposed between the bridge rectifier and the secondary coil, and (ii) assertion of a voltage control signal generated responsive to monitoring a target voltage level of the charging voltage generated by the bridge rectifier; monitoring, by the external charger, a rate of occurrence of clamping at the secondary coil; and responsive to the monitoring of the rate of occurrence of clamping, modifying the frequency of RF power generated by the primary coil.

2 . The method as recited in claim 1 , wherein the rate of occurrence of clamping is monitored over a defined period of time.

3 . The method as recited in claim 2 , wherein the frequency is increased to lower the RF power responsive to determining that the rate of occurrence of clamping over the defined period of time is greater than a predetermined threshold.

4 . The method as recited in claim 2 , wherein the frequency is reduced to increase the RF power responsive to determining that the rate of occurrence of clamping over the defined period of time is less than a predetermined threshold.

5 . The method as recited in claim 1 , wherein the series switch comprises an N-channel metal oxide semiconductor (NMOS) field-effect transistor (FET) device driven by a gate voltage derived from the series LC circuit configuration in an ON state.

6 . The method as recited in claim 5 , wherein the NMOS device is opened in the OFF state by clamping the gate voltage to a ground using a first FET device of the coil clamp circuit that is driven by a clamp control signal generated by the voltage regulation circuitry.

7 . The method as recited in claim 6 , wherein the coil clamp circuit comprises a second FET device disposed in a parallel circuit configuration with the first FET device, the second FET device coupled to the second electrical node of the series LC circuit configuration and driven by the clamp control signal generated by the voltage regulation circuitry.

8 . The method as recited in claim 1 , wherein the voltage regulation circuitry comprises a first comparator configured to compare a target voltage level of the charging voltage generated by the bridge rectifier with an internal reference voltage associated with the first comparator.

9 . The method as recited in claim 8 , wherein an output of the first comparator is coupled to a grounded loading resistor for preventing asserting a logic high value of the clamp control signal until an operating voltage of the first comparator comprising the target voltage level is reached.

10 . The method as recited in claim 8 , wherein the voltage regulation circuitry comprises a second comparator configured to compare an over-voltage shutoff level that is greater than the target voltage level by a select amount with an internal reference voltage associated with the second comparator.

Assignees

• Advanced Neuromodulation Systems Inc

Inventors

• Winstrom William

Classifications

• H02J2105/46

  Medical devices, medical implants or life supporting devices · CPC title

• H02J50/20

  using microwaves or radio frequency waves · CPC title

• H02J50/10

  using inductive coupling · CPC title

• A61N1/37229

  Shape or location of the implanted or external antenna · CPC title

• H02J50/80

  involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices · CPC title