Microprocessor controlled class E driver

• US 9,166,441 B2
• Filed: 01/09/2015
• Issued: 10/20/2015
• Est. Priority Date: 07/29/2013
• Status: Active Grant

• Current Assignee: Alfred E. Mann Foundation For Scientific Research
• Original Assignee: Alfred E. Mann Foundation For Scientific Research
• Inventors: Dearden, Brian R., Wolfe, James H., Khemani, Manish
• Primary Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US14/593,781
• Publication Number:
  US 20150123608A1
• Time in Patent Office: 284 Days
• Field of Search: 320/108
• US Class Current: 1/1
• CPC Class Codes: A61N 1/36125 Details of circuitry or electric components
• CPC Class Codes: A61N 1/37223 Circuits for electromagnetic coupling
• CPC Class Codes: A61N 1/3727 characterised by the modulation technique
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H03C 3/00 Angle modulation H03C5/00, H03C7/00 take precedence
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A charger including a class E power driver, a frequency-shift keying (“FSK”) module, and a processor. The processor can receive data relating to the operation of the class E power driver and can control the class E power driver based on the received data relating to the operation of the class E power driver. The processor can additionally control the FSK module to modulate the natural frequency of the class E power transformer to thereby allow the simultaneous recharging of an implantable device and the transmission of data to the implantable device. The processor can additionally compensate for propagation delays by adjusting switching times.

Claims

1. A portable charger device for transcutaneous charging of an implantable neurostimulator in a patient, the charger device comprising:

a housing having an external surface that is configured to at least partially engage a skin surface of the patient and be positioned at least partially over the implantable neurostimulator;

a charging coil disposed within the housing, wherein the charging coil is configured to generate a magnetic field having a frequency and to magnetically couple with the implantable neurostimulator to recharge the implantable neurostimulator;

a class E driver disposed within the housing and electrically coupled to the charging coil, wherein the class E driver comprises;

a switching circuit, wherein the switching circuit is switched by the application of a first voltage to the switching circuit;

a current sensor positioned to sense a current passing through the charging coil;

an FSK module configured to modulate the frequency of the magnetic field among at least three frequencies; and

a processor disposed within the housing and electrically coupled to the class E driver, wherein the processor is configured to receive data indicative of the current passing through the charging coil and control the switching circuit via the application of the first voltage to the switching circuit in response to the received data, wherein the processor is configured to selectively operate the charger in either a data non-transmitting state or in a data transmitting state, wherein a carrier signal has the first frequency when the charger operates in the data non-transmitting state, and wherein the processor controls the FSK module to modulate the carrier signal between the second frequency and the third frequency when the charger operates in the data transmitting state.

2. The portable charger device of claim 1, wherein the FSK module allows modulation between 3 different frequencies so as to improve efficiency of data transmission simultaneous with recharging.

3. The portable charger device of claim 1, wherein the processor is configured to control the FSK module to modulate the frequency of the magnetic field.

4. The portable charger device of claim 3, wherein the FSK module comprises two capacitors and two transistors, wherein the two transistors are controllably connected to the processor such that the two capacitors can be selectively included within the circuit by the FSK module to modulate the frequency of the magnetic field between the first, second, and third frequencies.

5. The portable charger device of claim 1, wherein the processor is electrically connected to the class E driver to receive data indicative of a second voltage of the switching circuit.

6. The portable charger device of claim 5, wherein the processor is further configured to:

receive data indicative of the second voltage of the switching circuit; and

control the switching circuit in response to the received data indicative of the second voltage of the switching circuit.

7. The portable charger device of claim 1, wherein the processor is configured to:

sense a power switching transistor voltage; and

determine whether to adjust a first frequency with which the first voltage is applied to the switching circuit, wherein the adjustment of the first frequency mitigates one or several propagation delays.

8. The portable charger device of claim 7, wherein the processor is configured to retrieve a stored value identifying a second frequency with which the first voltage is applied based on the sensed power switching transistor voltage.

9. The portable charger device of claim 8, wherein the processor is configured to compare the retrieved stored value identifying the second frequency with which the first voltage is applied to one or several frequency limits.

10. The portable charger device of claim 9, wherein the first frequency is set to the second frequency if the second frequency does not exceed the one or several frequency limits.

11. The portable charger device of claim 9, wherein when the second frequency exceeds one of the one or several frequency limits, the first frequency is set to the exceeded one of the one or several frequency limits.

12. A method of controlling transcutaneous charging of an implantable neurostimulator in a patient with a charger device, the method comprising:

magnetically coupling the charger device and the implantable neurostimulator, wherein the magnetic coupling of the charger device with the implantable neurostimulator charges the implantable neurostimulator;

setting an initial frequency of a drive signal, wherein the initial frequency of the drive signal is set by a processor, and wherein the drive signal controls opening and closing of a switch;

identifying a time of a current zero-crossing transition;

sensing a voltage at the switch at the time of the current zero-crossing transition;

retrieving a value identifying a second frequency based on the voltage at the switch at the time of the current zero-crossing transition; and

changing the frequency of the drive signal.

13. The method of claim 12, wherein changing the frequency of the drive signal comprises changing the frequency of the drive signal from the first frequency to the second frequency.

14. The method of claim 13, comprising retrieving one or several frequency limits, wherein the frequency limits provide an upper and lower bound to a range of acceptable frequencies of the drive signal.

15. The method of claim 14, comprising comparing the second frequency to the one or several frequency limits.

16. The method of claim 15, wherein changing the frequency of the drive signal comprises changing the frequency of the drive signal from the first frequency to the one of the one or several frequency limits if the second frequency exceeds the one of the one or several frequency limits.

17. The method of claim 15, wherein changing the frequency of the drive signal comprises changing the frequency of the drive signal from the first frequency to the second frequency if the second frequency does not exceed the one or several frequency limits.

18. The method of claim 17, further comprising modulating the frequency of the drive signal with an FSK module to transition between a data transmitting state and a data non-transmitting state.