Ultra-low-power and High-accuracy CMOS Temperature Sensor

This paper presents an integrated CMOS temperature sensor based on resistance sensing, taking a frequency-to-digital readout, which makes the overall structure simple while enabling high accuracy in a wide temperature range of -40 °C to 125 °C. The temperature sensing element employs relaxation oscillators with thermistors to output temperature-dependent frequency signals, inheriting the linearity of the resistance with respect to temperature. In addition, the sensor itself generates a frequency without the need to input an external clock, expanding the application scenarios. The digital code output of the readout circuit stands for the frequency ratio, thereby mitigating the effects of supply voltage fluctuations.