Circuit for an implantable device

1. An integrated circuit for an implantable wirelessly powered device for implantation in a patient's body, the integrated circuit comprising:

a radio-frequency (RF) to direct current (DC) rectifying circuit coupled to one or more antennas of the implantable wirelessly powered device, the rectifying circuit configured to:

rectify an input RF signal received at the one or more antennas and from an external controller through non-inductive coupling; and

extract DC electrical energy from the input RF signal;

a logic control circuit connected to the rectifying circuit and a driving circuit, the logic control circuit configured to:

extract waveform parameters from the rectified input RF signal;

generate a current for the driving circuit using the extracted DC electrical energy;

generate one or more electrical impulses according to the extracted waveform parameters; and

the driving circuit coupled to one or more electrodes and further comprises current mirrors, a shunt resistor controller, and a switch network, the driving circuit configured to:

deliver the one or more electrical impulses through the one or more electrodes to modulate neural tissue within the patient's body,

wherein the switch network is coupled to the current mirrors for delivering the one or more electrical impulses to the one or more electrodes, and wherein the shunt resistor controller is configured to couple a shunt resistor to the switch network at an end of an electrical impulse.

2. The integrated circuit of claim 1 , wherein the one or more antennas comprise one or more patch antennas, one or more slot antennas, or one or more dipole antennas.

3. The integrated circuit of claim 1 , wherein the one or more antennas comprise one or more differential dipole antennas.

4. The integrated circuit of claim 1 , wherein the logic control circuit is further configured to set polarity state for each electrode during a communication initialization pulse of the input RF signal.

5. The integrated circuit of claim 1 , wherein the logic control circuit is configured to generate the one or more electrical impulses that result in a substantially zero net charge at the one or more electrodes.

6. The integrated circuit of claim 1 , wherein the driving circuit comprises: a current source digital to analog circuit (DAC), and a current sink digital to analog circuit (DAC), the current source DAC and the current sink DAC being complementary to each other and both being connected to each electrode via current mirrors.

7. The integrated circuit of claim 1 , wherein the driving circuit comprises: a switch network configured to control a polarity state for each electrode.

8. The integrated circuit of claim 1 , wherein the driving circuit comprises:

a variable shunt resistor adapted to reduce a ripple on the electrode connected thereto when the electrical impulse has just ended.

9. The integrated circuit of claim 1 , further comprising: a discharge delay timer to delay an onset of discharge of capacitors coupled to each of the electrodes.

10. The integrated circuit of claim 1 , wherein the rectifying circuit comprises a diode bridge.

11. The integrated circuit of claim 1 , wherein the rectifying circuit comprises: an amplitude modulation detection circuit to extract the electrical energy from the rectified input RF signal.

12. An implantable wirelessly powered device to modulate neural tissue within a patient's body, comprising:

one or more electrodes;

one or more antennas; and

an integrated circuit, the integrated circuit comprising:

a radio-frequency (RF) to direct current (DC) rectifying circuit coupled to the one or more antennas, the rectifying circuit configured to:

 rectify an input RF signal received at the one or more antennas and from an external controller through non-inductive coupling; and

 extract DC electrical energy from the input RF signal; and

a logic control circuit connected to the rectifying circuit and a driving circuit, the logic control circuit configured to:

 extract waveform parameters from the rectified input RF signal;

 generate a current for the driving circuit using the extracted DC electrical energy; and

 generate one or more electrical impulses according to the extracted waveform parameters,

wherein the driving circuit is coupled to the one or more electrodes and further comprises current mirrors, a shunt resistor controller, and a switch network, the driving circuit configured to:

 deliver the one or more electrical impulses through the one or more electrodes to modulate neural tissue within the patient's body,

wherein the switch network is coupled to the current mirrors for delivering the one or more electrical impulses to the one or more electrodes, and wherein the shunt resistor controller is configured to couple a shunt resistor to the switch network at an end of an electrical impulse.

13. The implantable wirelessly powered device of claim 12 , wherein the one or more antennas are configured to receive the input RF signal through non-inductive coupling, and wherein the implantable wirelessly powered device does not include a battery.

14. The implantable wirelessly powered device of claim 12 , wherein the one or more antennas comprise one or more patch antennas, one or more slot antennas, or one or more dipole antennas.

15. The implantable wirelessly powered device of claim 12 , wherein the logic control circuit is further configured to set polarity state for each electrode during a communication initialization pulse of the input RF signal.

16. The implantable wirelessly powered device of claim 12 , wherein the logic control circuit is configured to generate the one or more electrical impulses that result in a substantially zero net charge at the one or more electrodes.

17. A system configured to modulate neural tissue within a patient's body, comprising:

an external controller; and

an implantable wirelessly powered device, comprising:

one or more electrodes;

one or more antennas; and

an integrated circuit, the integrated circuit comprising:

a radio-frequency (RF) to direct current (DC) rectifying circuit coupled to the one or more antennas, the rectifying circuit configured to:

rectify an input RF signal received at the one or more antennas from the external controller through non-inductive coupling; and

extract DC electrical energy from the input RF signal; and

a logic control circuit connected to the rectifying circuit and a driving circuit, the logic control circuit configured to:

extract waveform parameters from the rectified input RF signal;

generate a current for the driving circuit using the extracted DC electrical energy; and

generate one or more electrical impulses according to the extracted waveform parameters,

wherein the driving circuit is coupled to the one or more electrodes and further comprises current mirrors, a shunt resistor controller, and a switch network, the driving circuit configured to:

deliver the one or more electrical impulses through the one or more electrodes to modulate neural tissue within the patient's body,

wherein the switch network is coupled to the current mirrors for delivering the one or more electrical impulses to the one or more electrodes, and wherein the shunt resistor controller is configured to couple a shunt resistor to the switch network at an end of an electrical impulse.

18. The system of claim 17 wherein the one or more antennas are configured to receive the input RF signal through non-inductive coupling, and wherein the implantable wirelessly powered device does not include a battery.

19. The system of claim 17 wherein the logic control circuit is configured to generate the one or more electrical impulses that result in a substantially zero net charge at the one or more electrodes.