A CMOS Temperature Sensor With Versatile Readout Scheme and High Accuracy for Multi-Sensor Systems

• Published in: IEEE transactions on circuits and systems. I, Regular papers Vol. 65; no. 11; pp. 3821 - 3829
• Main Authors: Tang, Zhong, Fang, Yun, Yu, Xiao-Peng, Shi, Zheng, Tan, Nianxiong
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Analog circuits; Circuit design; Circuits; CMOS; CMOS process; CMOS temperature sensor; Complexity theory; multi-sensor; Photonic band gap; Sensitivity; Sensors; Silicon; start-up; substrate PNP; Temperature measurement; Temperature sensors; Thermometers; versatile readout scheme
• ISSN: 1549-8328; 1558-0806
• DOI: 10.1109/TCSI.2018.2853649

In this paper, a smart CMOS temperature sensor with a versatile readout scheme is presented. A digital-assisted readout solution is proposed to improve the compatibility of the circuit and maintain the performance of a traditional smart temperature sensor. In addition, the potential multi-operating points of the analog front-end are analyzed, and a compact start-up circuit is designed to make the analog front-end work properly. Fabricated in a standard 0.13 <inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula> CMOS process, the proposed temperature sensor occupies a silicon area of 0.29 mm 2 and draws a current of <inline-formula> <tex-math notation="LaTeX">95~\mu \text{A} </tex-math></inline-formula> from a 2 to 3.6 V supply voltage at the room temperature. Measured results show that the proposed design has the inaccuracy of ± 0.47 °C (<inline-formula> <tex-math notation="LaTeX">3\sigma </tex-math></inline-formula>) from −40 °C to 125 °C after a single-point temperature calibration. It achieves a resolution of 16 mK at a conversion time of 5.12 ms and a supply sensitivity of less than 0.05 °C/V. Thanks to the versatile readout scheme, the proposed temperature sensor is compatible with multi-sensor systems where the readout-circuitry can be shared between different input signals.