A Low Power BJT-Based CMOS Temperature Sensor Using Dynamic-Distributing-Bias Circuit

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 0.153 mu m CMOS process, the sensor shows a measured inaccuracy of-0.6 degrees C to +0.8 degrees C from -40 degrees C to 125 degrees C. This performance is obtained by using precision and nonlinearity compensation techniques such as VBE trimming, ratio-metric curvature correction, chopping and dynamic element matching (DEM). The sensor has low power consumption of 2.21 mu W under a 1.6 V supply and occupies an area of 0.07 mm(2).