A Low-Voltage and Low-Power CMOS Temperature Sensor Circuit with Digital Output for Wireless Healthcare Monitoring System

This paper describes a low-voltage and low-power temperature sensor circuit with digital interface for wireless healthcare monitoring system. The proposed circuit consists of temperature sensor core circuit and digital interface circuit. Both circuits are able to be operated at 1.0 V. The proposed temperature sensor circuit is operated in weak inversion region of MOSFETs. The proposed digital interface circuit converts current into time using Current-to-Time Converter (ITC). The proposed circuit is simulated using HSPICE with 1P, 5M, 3-well, 0.18-μm CMOS process (BSIM3v3.2, LEVEL53). From the simulation, it is obtained that temperature range is 33 °C to 45 °C, resolution of proposed circuit is 0.059 °C with +0.076/-0.075 °C inaccuracy and the total power consumption is 23.2 μW.