Delta-Sigma modulated output temperature sensor for 1V voltage supply

Abstract

This work presents a temperature sensor with a digital Delta-Sigma modulated output designed to work at a supply voltage as low as 1V to operate in a temperature range from −20°C to +125°C. A bandgap current reference circuit generates a current proportional to the temperature (PTAT) and a reference current. Both currents are integrated in a capacitor within a Delta-Sigma modulator, resulting in a digital output whose average value is proportional to the temperature. The sensor was designed using the 180nm TSMC technology and occupies an area of 285µm×190µm. Simulations showed a maximum nonlin-earity of 0.31% and a duty cycle variation of 0.531% per Cel-sius. The sensor power consumption is 120µW.