A Wirelessly Powered CMOS Electrochemical Sensing Interface With Power-Aware RF-DC Power Management

Abstract

A wirelessly powered electrochemical sensing chip with high-efficiency adaptive power management for a wide RF-powering range and a low-noise chopper-stabilization potentiostat for high-resolution electrochemical current detection is presented. The chip is fabricated using a 0.18-mu m CMOS process. A novel, power-aware, multiple-path, RF-energy harvesting front end extends the high-efficiency (> 20%) RF-powering range to 8.5 dB. In the sensor-readout interface, a chopper-stabilization potentiostat with an oscillator-based current readout achieves a 3.3-pA current resolution in the current range of 800nA and an R-2 linearity of 0.9987 while consuming only 4.4 mu W. The power efficiency of the electrochemical readout interface is 0.18, and the dynamic detection range is 107 dB.