Integrated ultra-low power precision rectifiers for implantable medical devices

Abstract

Two ultra-low power CMOS full-wave precision rectifiers are presented. The rectifiers require no diodes and utilize a single or two transconductors (OTA) as the active element, reducing power consumption to a minimum. Firstly, a voltage to current rectifier consuming 120nA is presented, and used to estimate the amplitude of a piezoelectric accelerometer output in an adaptive pacemaker. Then, a new voltage rectifier consuming less than 10nA is presented, and later utilized in a cardiac sensing channel circuit also for pacemakers, incorporating the rectifier to detect positive and negative voltage signal spikes. Both rectifiers were designed in a 0.6μm CMOS technology, fabricated, tested. Measurement results closely fit the expected performance.