23.2 A 70µW 1.19mm2 Wireless Sensor with 32 Channels of Resistive and Capacitive Sensors and Edge-Encoded PWM UWB Transceiver

Abstract

Emerging wireless multi-channel resistive and capacitive (RC) sensor interface circuits provide opportunities for various applications such as environmental monitoring [1], wearable [2] and human-computer interaction [3]. Previous works either only support single-channel sensor readout [1], or lack efficient wireless transmission [2], [5]. This work presents an energy- and area-efficient wireless multi-channel RC sensor node for electronic skins. In this sensor node, a COMA-like resistance/capacitance-to-voltage converter (RCVC) is proposed to simultaneously record 16-channel resistive and 16-channel capacitive sensors with compact chip area. In addition, an edge-encoded PWM UWB radio is incorporated for wireless data transmission. The power efficiency of the sensor node is further boosted by duty-cycling.