Micropower Electronic Switches for Implanted Instrumentation

Low-power miniature switching circuits for controlling the power supply to an implanted electronic circuit are described. These circuits can be used as power supply switches for conserving battery power on implanted systems. Monostable and bistable switches that can be triggered either by radio-frequency energy or light are presented. Circuits, having standby currents as low as 25 nA and operated at voltages of 1.35 V, are described. A hybrid microelectronics realization of a radio-frequency triggered bistable switch is described. Radio-frequency triggering by induction can be carried out over distances ranging from 2 to 10 cm, depending on the circuit used. Light triggering using either electronic photoflash lamps or low-power incandescent lights can be achieved over distances as great as 250 cm.