Design of a Novel Ultra-Low Power Time-Domain Temperature Sensor

Abstract

This paper proposed a novel ultra-low power time-domain temperature sensor. It consists of two current generators including one constant-with-temperature (CWT) current reference generator, relaxation oscillator, separation circuit and digital circuit system. Both of current generators are used to drive the oscillator to produce a signal whose high level duration is complementary to absolute temperature, and low level duration is temperature-independent. The separation circuit is used to separate the high level duration and low level duration. The digital circuit system can quantify the separation circuit output and make a subtraction, and therefore obtain digitized temperature information. The temperature sensor is designed using a standard 0.18μm CMOS process. The simulation results show that it can measure temperature from 0°C to 60°C The power consumption of the complete system is 86.79 nW at 25°C The maximum conversion speed is 52 Sa/s under 1V voltage supply.