A PWM output temperature sensor

摘要

This work shows a temperature sensor with a digital 1-bit PWM output fabricated in the 0.6 μm XFAB CMOS process. The sensor is based on a Bandgap voltage reference circuit, which is used to generate a current proportional to the temperature I_PTAT and a reference current I_REF. Both currents are used to charge and discharge a capacitor of the PWM modulator, resulting in a square wave output, where the duty cycle is a proportion between both currents. The sensor was designed to operate from -40°C to +125°C with 5V of power supply.