A High-Speed Temperature Sensor with Low Supply Sensitivity for SoC Thermal Monitoring

作者：Bao, Yuanxin; Li, Wenyuan^*

来源：Journal of Circuits, Systems, and Computers, 2018, 27(7): 1850116.

DOI：10.1142/S0218126618501165

• Time-domain temperature sensor
• high speed
• low supply sensitivity
• low energy dissipation
• frequency-to-digital converter

A high-speed low-supply-sensitivity temperature sensor is presented for thermal monitoring of system on a chip (SoC). The proposed sensor transforms the temperature to complementary to absolute temperature (CTAT) frequency and then into digital code. A CTAT voltage reference supplies a temperature-sensitive ring oscillator, which enhances temperature sensitivity and conversion rate. To reduce the supply sensitivity, an operational amplifier with a unity gain for power supply is proposed. A frequency-to-digital converter with piecewise linear fitting is used to convert the frequency into the digital code corresponding to temperature and correct nonlinearity. These additional characteristics are distinct from the conventional oscillator-based temperature sensors. The sensor is fabricated in a 180 nm CMOS process and occupies a small area of 0.048 mm(2) excluding bondpads. After a one-point calibration, the sensor achieves an inaccuracy of +/- 1.5 degrees C from -45 degrees C to 85 degrees C under a supply voltage of 1.4-2.4V showing a worst-case supply sensitivity of 0.5 degrees C/V. The sensor maintains a high conversion rate of 45 KS/s with a ne resolution of 0.25 degrees C/LSB, which is suitable for SoC thermal monitoring. Under a supply voltage of 1.8 V, the maximum energy consumption per conversion is only 7.8 nJ at -45 degrees C.

• 出版日期2018-6-30
• 单位东南大学