A low power BJT-based CMOS temperature sensor using dynamic-distributing-bias circuit

Abstract

A low power dynamic-distributing-bias CMOS temperature sensor is presented for temperature-sensing RFID tag. To reduce the chip area and power consumption, we propose a new hybrid PTAT/REF current generator. A new current-mode readout scheme is devised, which is dedicated to improve the dynamic range utilization of ADC and further reduce the power consumption. Fabricated in 0.153µm CMOS process, the sensor shows a measured inaccuracy of -0.6°C to +0.8°C from -40°C to 125°C. This performance is obtained by using precision and nonlinearity compensation techniques such as V_BE trimming, ratio-metric curvature correction, chopping and dynamic element matching (DEM). The sensor has low power consumption of 2.21µW under a 1.6V supply and occupies an area of 0.07mm².