A simple remote-controlled power switch for internalized bioelectronic instrumentation

The authors present a remote-controlled power switch for extending the battery life of biomedical instruments implanted into animals or humans. The switching action is controlled externally to the implant by an inductive link between two coils, one contained in the implant and one external to the implant. The external coil sends an electromagnetic pulse to the implant, triggering a CMOS D flip-flop connected as a toggle switch; its state is toggled on or off upon receiving the external pulse. The standby current drain of the switch is about 4 nA. The remote triggering range is approximately 20-50 cm. Testing of the switch, surgically implanted as part of a telemetry transmitter, is also discussed.