A 28 mK Resolution, −0.45 °C/+0.51 °C Inaccuracy Temperature Sensor Using Dual-Comparator Architecture and Logic-Controlled Counting Method

This paper presents an all-CMOS temperature sensor with low power consumption, wide temperature range, and high precision in a 180 nm CMOS process. Based on the I–V characteristics of MOSFETs in the subthreshold region and the negative exponential biasing current generated by the self-bootstrapped bias circuit, the proposed temperature-sensing front-end produces CTAT and PTAT voltages with high linearity and high sensitivity. The voltage-to-time converter (VTC) adopts a dual-comparator architecture to expand the time interval for improving resolution. The control logic unit is designed to count only within the time interval, eliminating interference during low-level periods and enhancing the accuracy of temperature measurement. The implemented sensor achieves an inaccuracy of −0.45 °C/+0.51 °C (3σ) from −40 °C to 130 °C after a two-point calibration with a resolution of 28 mK and consumes 503 nW at 27 °C when operating at 1 V, with an FoM of 7.9 pJ·K2.