A Silicon-on-Sapphire Low-Voltage Temperature Sensor for Energy Scavengers

Abstract

The paper report on the design and test of a low-voltage temperature sensor designed for MEMS power-harvesting systems. The core of the sensor is a bandgap voltage reference circuit operating with a supply voltage in the range of 1-1.5V. The prototype was fabricated on a conventional 0.5mum silicon-on-sapphire (SOS) process. The sensor design consumes 15muA of current at 1V. The internal reference voltage is 550mV. The temperature sensor has a digital square wave output whose frequency is proportional to temperature. A linear model of the dependency of output frequency with temperature has a conversion factor of 1.6kHz/degC. The output is also independent of supply voltage in the range of 1-1.5V. Measured results and targeted applications for the proposed circuit were reported.