Abstract: A cochlea stimulation system includes a patient wearable system comprising an externally wearable signal processor (WP) and a headpiece in electronic communication with an implanted cochlear stimulator (ICS). The ICS comprises eight output stages each having two electrically isolated capacitor-coupled electrodes, designated "A" and "B", circuits for monitoring the voltages on these electrodes, and circuits for both transmitting status information to and receiving control information from the WP. Based upon information received from the WP, a processor within the ICS can control both the frequency and the widths of the output stimulation pulses applied to the electrodes and may select which electrodes to monitor. The ICS receives power and data signals telemetrically through the skin from the WP. To save power, the ICS may be "powered down" by the WP based upon the absence of audio information or "powered up" if audio is present.

Abstract: A low power current-to-frequency converter circuit provides an output frequency signal F.sub.OUT having a frequency that varies as a function of a low level analog input current signal. The analog input current signal is typically generated by an implantable sensor element, designed to sense a particular substance or parameter within body tissue or fluids to which the sensor is exposed, with the magnitude of the analog signal providing a measure of the sensed substance or parameter. Conversion of the low level analog current to the output frequency signal facilitates transmission of the data signal over a shared data bus and other digital processing of the data signal.