Fully integrated power supply design for wireless biomedical implants

Abstract

Describes the implementation of several fully integrated on-chip rectifier designs in BiCMOS technology for rectifying the externally generated RF magnetic power and data carrier signal in wireless biomedical implants to generate an unregulated DC supply. It also presents application of these rectifiers in an integrated dual /spl plusmn/5 V output supply capable of providing up to 50 mW for wireless biomedical implants. New full-wave rectifier topologies and low power circuit design techniques have been employed to decrease substrate leakage current and parasitic components, reduce the possibility of latch-up, and improve power transfer efficiency and high frequency performance of the rectifier block. These circuits have been designed to be used in a wireless neural stimulating microsystem and fabricated in the University of Michigan's single-metal, dual-poly 3-/spl mu/m BiCMOS process. The rectifier areas are in the range of 0.12 to 0.48 mm/sup 2/ and they are capable of delivering more than 100 mW from the receiver coil to the regulator circuitry. The performance of all rectifier designs has been tested and compared using up to 4 MHz carrier.