A temperature sensor with error compensation based on voltage-to-frequency converter

This paper proposes a BJT-based frequency-domain temperature sensor of a voltage-to-frequency converter (VFC) and error compensation. The key design is that the two base-emitter voltages from the detection front end are converted by VFC into corresponding frequency signals. To achieve high accuracy, an error compensation method calibrates errors arising from the VFC loop delay and comparator offset. Implemented in a 0.18μm SMIC process, the sensor achieves an error of -0.35°C∼+0.75°C throughout a temperature range of the -40°C∼125°C. The sensor has an average conversion time of 3.5ms, a power consumption of 270μW, and an area of just 0.065mm2.