Circuit for an implantable device
An integrated circuit includes: a radio-frequency (RF) to direct current (DC) rectifying circuit coupled to one or more antenna on an 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 electric radiative coupling; and extract DC electric power and configuration data from the input RF signal; a logic control circuit connected to the rectifying circuit and a driving circuit, the logic control circuit configured to: generate a current for the driving circuit solely using the extracted DC electrical power; in accordance with the extracted configuration data, set polarity state information for each electrode; and a driving circuit coupled to one or more electrode, the driving circuit comprising current mirrors and being configured to: steer, to each electrode and via the current mirrors, a stimulating current solely from the generated current.
1. A device for implantation in a patient, the device comprising:
one or more electrodes configured to deliver one or more electrical impulses to neural tissue of the patient;
a dipole antenna in a differential configuration that includes a first portion and a second portion, the antenna configured to receive a radio-frequency signal;
a full-wave rectification circuit coupled to the first portion and the second portion of the antenna, the rectification circuit configured to generate a direct current voltage from the radio-frequency signal via electrical radiative coupling, wherein the direct current voltage is the electrical power used to generate the one or more electrical impulses;
a voltage converter configured to convert the direct current voltage to a second voltage; and
a driving circuit coupled between the rectification circuit and the one or more electrodes, the driving circuit including one or more current mirrors and configured to:
drive the one or more electrical impulses to the one or more electrodes via the one or more current mirrors, and
change from a driving state to a high-impedance state in response to the second voltage being below a threshold voltage that is greater than zero.
2. The device of claim 1 , wherein the driving circuit includes a current source device and a current sink device that are coupled to the one or more current mirrors, wherein during delivery of an electrical impulse the one or more electrodes are coupled to one of the current source device and the current sink device.
3. The device of claim 1 , further comprising a shunt resistor controller coupled to the one or more electrodes, the shunt resistor controller configured to couple a resistance to the one or more electrodes.
4. The device of claim 3 , wherein a value of the resistance is variable and the variable resistance value is selected based on an instruction received by the antenna.
5. The device of claim 1 , wherein the antenna is embedded into the device.
6. The device of claim 1 , further comprising a circuit board to which at least one of the rectification circuit and the driving circuit is coupled, wherein the antenna is directly connected to the circuit board.
7. The device of claim 6 , further comprising a shunt resistor controller coupled to the one or more electrodes, the shunt resistor controller configured to couple a variable resistance to the one or more electrodes and a value of the variable resistance is selected based on an instruction received by the antenna.
8. A system to modulate neural tissue, the system comprising:
a controller configured to generate a radio-frequency signal; and
a device configured for implantation within a patient, the device comprising:
one or more electrodes configured to deliver one or more electrical impulses to neural tissue of the patient;
a dipole antenna in a differential configuration that includes a first portion and a second portion, the antenna configured to receive the radio-frequency signal;
a full-wave rectification circuit coupled to the first portion and the second portion of the antenna, the rectification circuit configured to generate a direct current voltage from the radio-frequency signal via electrical radiative coupling, wherein the direct current voltage is the electrical power used to generate the one or more electrical impulses;
a voltage converter configured to convert the direct current voltage to a second voltage; and
a driving circuit coupled between the rectification circuit and the one or more electrodes, the driving circuit including one or more current mirrors and configured to:
drive the one or more electrical impulses to the one or more electrodes via the one or more current mirrors, and
change from a driving state to a high-impedance state in response to the second voltage being below a threshold voltage that is greater than zero.
9. The system of claim 8 , wherein the driving circuit includes a current source device and a current sink device that are coupled to the one or more current mirrors, wherein during delivery of an electrical impulse the one or more electrodes are coupled to one of the current source device and the current sink device.
10. The system of claim 8 , wherein the device further comprises a shunt resistor controller coupled to the one or more electrodes, the shunt resistor controller configured to couple a resistance to the one or more electrodes.
11. The system of claim 10 , wherein a value of the resistance is variable and the variable resistance value is selected based on an instruction received by the antenna.
12. The system of claim 8 , wherein the antenna is embedded into the device.
13. The system of claim 8 , wherein the device further comprises a circuit board to which at least one of the rectification circuit and the driving circuit is coupled, wherein the antenna is directly connected to the circuit board.
14. The system of claim 13 , wherein the device further comprises a shunt resistor controller coupled to the one or more electrodes, the shunt resistor controller configured to couple a variable resistance to the one or more electrodes and a value of the variable resistance is selected based on an instruction received by the antenna.
15. A method to stimulate tissue, the method comprising:
obtaining a radio-frequency signal at a dipole antenna in a device implanted in a patient, the dipole antenna being in a differential configuration that includes a first portion and a second portion;
generating, by a full-wave rectification circuit in the device that is coupled to the first portion and the second portion of the antenna, a direct current voltage from the radio-frequency signal via electrical radiative coupling;
generating, by the device, one or more electrical impulses, wherein the direct current voltage is the electrical power used to generate the one or more electrical impulses;
driving, via one or more current mirrors, the one or more electrical impulses to one or more electrodes of the device for delivery of the one or more electrical impulses to tissue of the patient; and
after driving the one or more electrical impulses, coupling a resistance to the one or more electrodes, wherein a value of the resistance is variable and the variable resistance value is selected based on an instruction received by the antenna.
16. The method of claim 15 , further comprising before driving the one or more electrical impulses to the one or more electrodes, selectively coupling the one or more of the electrodes to the one or more current mirrors.
17. The method of claim 15 , further comprising:
converting the direct current voltage to a second voltage; and
changing a driving circuit of the device that drives the one or more electrical impulses from a driving state to a high-impedance state in response to the second voltage being below a threshold voltage that is greater than zero.
18. A system to modulate neural tissue, the system comprising:
a controller configured to generate a radio-frequency signal; and
a device configured for implantation within a patient, the device comprising:
one or more electrodes configured to deliver one or more electrical impulses to neural tissue of the patient;
an antenna in a differential configuration that includes a first portion and a second portion, the antenna configured to receive the radio-frequency signal;
a rectification circuit coupled to the first portion and the second portion of the antenna, the rectification circuit configured to generate a direct current voltage from the radio-frequency signal via electrical radiative coupling, wherein the direct current voltage is the electrical power used to generate the one or more electrical impulses;
a shunt resistor controller coupled to the one or more electrodes, the shunt resistor controller configured to couple a variable resistance to the one or more electrodes and a value of the variable resistance is selected based on an instruction received by the antenna; and
a driving circuit coupled between the rectification circuit and the one or more electrodes, the driving circuit including one or more current mirrors and configured to drive the one or more electrical impulses to the one or more electrodes via the one or more current mirrors.
19. The system of claim 18 , wherein the driving circuit includes a current source device and a current sink device that are coupled to the one or more current mirrors, wherein during delivery of an electrical impulse the one or more electrodes are coupled to one of the current source device and the current sink device.
20. The system of claim 18 , wherein the device further includes a voltage converter configured to convert the direct current voltage to a second voltage, wherein the driving circuit changes from a driving state to a high-impedance state in response to the second voltage being below a threshold voltage that is greater than zero.
21. The system of claim 18 , wherein the antenna is embedded into the device.
22. A method to stimulate tissue, the method comprising:
obtaining a radio-frequency signal at a dipole antenna in a device implanted in a patient, the dipole antenna being in a differential configuration that includes a first portion and a second portion;
generating, by a rectification circuit in the device that is coupled to the first portion and the second portion of the antenna, a direct current voltage from the radio-frequency signal via electrical radiative coupling;
converting the direct current voltage to a second voltage;
generating, by the device, one or more electrical impulses, wherein the direct current voltage is the electrical power used to generate the one or more electrical impulses; and
driving, via one or more current mirrors, the one or more electrical impulses to one or more electrodes of the device for delivery of the one or more electrical impulses to tissue of the patient; and
changing a driving circuit of the device that drives the one or more electrical impulses from a driving state to a high-impedance state in response to the second voltage being below a threshold voltage that is greater than zero.
23. The method of claim 22 , further comprising before driving the one or more electrical impulses to the one or more electrodes, selectively coupling the one or more of the electrodes to the one or more current mirrors.
24. The method of claim 22 , further comprising coupling a resistance to the one or more electrodes, wherein a value of the resistance is variable and the variable resistance value is selected based on an instruction received by the antenna.
25. The method of claim 22 , wherein the antenna is embedded into the device.