On-chip CMOS bridge circuit

TLDR: In this paper, a bridge circuit is proposed to derive a power potential from an externally transmitted signal, with or without regulation, using a single CMOS integrated circuit, which can operate at carrier frequencies as high as several megahertz.

Abstract: There is disclosed a bridge circuit which finds particularly advantageous use in medical prostheses which can be programmed externally and which can transmit telemetry signals. The entire circuit is implemented on a single CMOS integrated circuit. Depending upon the values of two control bits, the bridge circuit functions to derive a powering potential from an externally transmitted signal, with or without regulation. Externally transmitted programming signals are detectable, and telemetry signals can be transmitted from the chip as well. There is no active switching of bridge devices during power rectification mode, and instead they are biased on continuously. This allows the rectifier to operate at carrier frequencies as high as several megahertz. All of this is achieved by using conventional CMOS processing techniques, without requiring any extra diffusion steps.