Abstract: The accuracy of neural response recordings in neural stimulators, e.g., cochlear implants, is often degraded by a recording artifact. An idealized electrical-equivalent model of a neural stimulator is created to study, measure and compensate for artifact evoked compound action potential (eCAP). Using this model, the artifact is shown to occur even when the electrical components that make-up the neural stimulator are ideal. The model contains parasitic capacitances between the electrode wires. The model demonstrates that these small parasitic capacitances provide a current path during stimulation which can deposit charge on the electrode-tissue interfaces of the recording electrodes. The dissipation of this residual charge and the charge stored across the stimulating electrode is seen as the recording artifact. The proposed solution for eliminating the artifact problem is realized by utilizing a capacitive electrode material, e.g.

Abstract: Systems and methods for providing a power signal to one or more implantable devices include a number of dynamic range amplifiers each having a multiplicity of output drivers. Each of the output drivers is configured to generate an output signal. The systems and methods further include control circuitry configured to select at least one of the amplifiers to provide a number of output signals used to generate the power signal that is to be provided to the one or more implantable devices. The control circuitry is further configured to disable the output drivers corresponding to a remaining number of amplifiers. A matching circuit is configured to generate the power signal based on the output signals provided by the at least one selected amplifier. The systems and methods further include means to transmit the power signal to the one or more implantable devices.

Abstract: A push-pull amplifier efficiency provides a 4:1 (12 dB) course adjustment of power output by using a single digital control input. The amplifier is provided with an input voltage (VDD) having sixteen steps ranging from 1.25 volts to 3.00 volts. Based on the digital control, an integrated circuit switches between a high power mode and a low power mode. In the low power mode, the output voltage is equivalent to the input voltage. In the high power mode, the amplifier provides an output of twice the input voltage (or four times the power).

Abstract: Monitoring/measurement circuitry within an implantable stimulator, e.g., an implantable cochlear stimulator (ICS), includes a first analog multiplexer (MUX) connected to a gain controlled, low noise, differential amplifier. The output of the differential amplifier is coupled to a second analog MUX along with other analog signals, e.g., operating or bias voltages used within the implantable stimulator. The signal appearing at the output of the second analog MUX is preliminary processed as required, e.g., to adjust the amplitude (attenuate) and/or filter out high frequency components. Once processed, the signal is then digitized in an analog-to-digital (A/D) converter. The digitized signal is then stored in memory as measured data, and eventually transmitted to a remote (non-implanted) processor for further processing, analysis, examination and/or feedback.