Microwave field stimulator
A system includes a controller module, which includes a storage device, a controller, a modulator, and one or more antennas. The storage device is stored with parameters defining a stimulation waveform. The controller is configured to generate, based on the stored parameters, an output signal that includes the stimulation waveform, wherein the output signal additionally includes polarity assignments for electrodes in an implantable, passive stimulation device. The modulator modulates a stimulus carrier signal with the output signal to generate a transmission signal. The one or more antennas transmit the transmission signal to the implantable, passive stimulation device such that the implantable, passive stimulation device uses energy in the transmission signal for operation, sets the polarities for the electrodes in the implantable, passive stimulation device based on the encoded polarity assignments, generates electrical pulses using the stimulation waveform, and applies the electrical pulses to excitable tissue.
1. A system, comprising:
an implantable passive stimulation device that does not have its own independent power source, the implantable passive stimulation device comprising one or more stimulation electrodes, a power-on reset circuit, control logic, stimulation circuitry, and a receiving antenna;
a controller module comprising:
a storage device configured to store parameters defining a stimulation waveform and polarity assignments for the stimulation electrodes of the implantable passive stimulation device;
a controller configured to generate, based on the stored parameters and polarity assignments, an output signal that includes an initial power-on portion followed by a configuration portion that encodes the polarity assignments followed by a stimulation portion that includes the stimulation waveform, wherein the stimulation portion is generated by modulating an envelope waveform on a carrier wave;
one or more antennas configured to transmit, in repeated cycles, the output signal non-inductively to the receiving antenna on the implantable passive stimulation device to generate power sufficient for electrodes on the implantable passive stimulation device to stimulate surrounding excitable tissue when the implantable passive stimulation device is implanted inside a patient such that for each particular repetition cycle of the output signal, (i) a power-on reset signal that resets the control logic is generated from the power-on portion of the received output signal, (ii) the polarity assignment information is decoded from the configuration portion of the received output signal to set the polarities for the stimulation electrodes, and (iii) electrical pulses are generated by demodulating the stimulation portion of the output signal to extract the stimulation waveform and then applied, using power generated from the output signal received non-inductively inside the patient, to excitable tissue according to the polarity assignment information decoded from the configuration portion that precedes the stimulation portion of the particular repetition cycle.
2. The system of claim 1 , wherein the controller module is configured to read a telemetry feedback signal from the implantable passive stimulation device, the telemetry feedback signal generated by solely using the output signal of the particular repetition cycle to power the implantable passive stimulator device to cause the implantable passive stimulator device to:
sense a first electrical parameter and a second electrical parameter concurrently; and
compare the first electrical parameter and the second electrical parameter to generate an analog feedback carrier frequency signal with a feedback carrier frequency that is proportional to a difference between the first electrical parameter and the second electrical parameter.
3. The system of claim 2 , wherein the controller module powers the implantable passive stimulation device to cause the telemetry feedback signal to be generated based on the first and second electrical parameters for which the first electrical parameter is a voltage over a reference resistor placed in serial connection with the electrode, and the second electrical parameter is a voltage over the electrode.
4. The system of claim 3 , wherein the controller module powers the implantable passive stimulation device to cause the telemetry feedback signal to be generated such that the feedback carrier frequency is proportional to a difference between a voltage over the reference resistor and a voltage over the electrode.
5. The system of claim 2 , wherein the controller module powers the implantable passive stimulation device to cause the telemetry feedback signal to be generated based on the first and second electrical parameters for which the first electrical parameter is a voltage over a reference resistor placed in serial connection with the electrode, and the second electrical parameter is a voltage over a calibration resister placed in parallel connection with the electrode.
6. The system of claim 5 , wherein the controller module powers the implantable passive stimulation device to cause the telemetry feedback signal to be generated such that the feedback carrier frequency is proportional to a difference between a voltage over the reference resistor and the voltage over the calibration resistor.
7. The system of claim 2 , wherein the controller module powers the implantable passive stimulation device to cause the telemetry feedback signal to be generated based on the first and second electrical parameters for which the first electrical parameter corresponds to a fixed voltage and the second electrical parameter is a voltage over one of: a calibration resistor, a reference resistor, an electrode.
8. The system of claim 1 , wherein the controller module powers the implantable passive stimulation device such that the power-on signal causes a handshake signal to be transmitted from implantable passive stimulation device to the controller module, the handshake signal confirms to the controller module that the implantable passive stimulation device is ready to receive polarity setting information.
9. The system of claim 1 , wherein the controller module powers the implantable passive stimulation device such that a handshake signal is received from the implantable passive stimulation device when the polarities for the electrodes are set according to the polarity assignment information encoded in the configuration portion, the handshake signal confirms to the controller module that the implantable, passive stimulator is ready to receive the stimulation portion of the output signal.