A CMOS Temperature Sensor with a Maximum Accuracy of 1.6 °C after One-Point Calibration

Abstract:

This paper presents a time-domain CMOS oscillator-based temperature sensor with one-point calibration for test cost reduction. Compared with the former CMOS sensors with linear delay lines, the proposed work composed of a temperature-to-pulse generator with adjustable time gain and a time-to-digital converter (TDC) can achieve lower circuit complexity and smaller area. A temperature-dependent oscillator for temperature sensing was used to generate the period width proportional to absolute temperature (PTAT). With the help of calibration circuit, an adjustable-gain time amplifier was adopted to dynamically adjust the amplified width that was converted by the TDC into the corresponding digital code. After calibration, the fluctuation of the sensor output with process variation can be greatly reduced. The maximum inaccuracy after one-point calibration for six package chips was 1.6 °C within a 0 80 °C temperature range. The proposed sensor fabricated in a 0.35-μm CMOS process occupied a chip area of merely 0.07 mm², achieved a fine resolution of 0.047 °C/LSB, and consumed a low power of 25 μW@10 samples/s.

• Periodical: Applied Mechanics and Materials (Volumes 336-338)
• Pages: 216-220
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.336-338.216
• Online since: July 2013
• Authors: Chun Chi Chen, Keng Chih Liu, Shih Hao Lin
• Keywords: CMOS, Delay Line, Oscillator, Temperature Sensor

References

[1] G. C. M. Meijer, G. Wang and F. Fruett, : Temperature sensors and voltage references implemented in CMOS technology: IEEE Sensors Journal, vol. 1 (2001) pp.225-234.

DOI: 10.1109/jsen.2001.954835

[2] P. Chen, C. -C. Chen, C. -C. Tsai and W. -F. Lu, : A time-to-digital-converter-based CMOS smart temperature sensor: IEEE J. Solid-State Circuits, vol. 40 (2005), p.1642–1648.

DOI: 10.1109/jssc.2005.852041

[3] M. K. Law and A. Bermak, A 405-nW CMOS temperature sensor based on linear MOS operation, IEEE Trans. Circuits Syst. II, vol. 56, no. 12, p.891–895, Dec. (2009).

DOI: 10.1109/tcsii.2009.2034201

[4] Y. -S. Lin, D. Sylvester, D. Blaauw, : An Ultra Low Power 1 V, 220 nW Temperature Sensor for Passive Wireless Applications: in Proc. IEEE CICC, (2008) pp.507-510.

DOI: 10.1109/cicc.2008.4672133

[5] K. Kim, H. Lee, S. Jung, and C. Kim, : A 366 kS/s 400 uW 0. 0013 mm frequency-to-digital converter based CMOS temperature sensor utilizing multiphase clock: in Proc. IEEE CICC, (2009), p.203–206.

DOI: 10.1109/tvlsi.2012.2220389

[6] C. -C. Chung and C. -R. Yang, : An Autocalibrated All-Digital Temperature Sensor for On-Chip Thermal Monitoring: IEEE Trans. Circuits Syst. II, vol. 58 (2011), p.105–109.

DOI: 10.1109/tcsii.2010.2104016

[7] K. Woo, S. Meninger, T. Xanthopoulos, E. Crain, D. Ha, and D. Ham, : Time-Domain CMOS Temperature Sensors With Dual Delay-Locked Loops for Microprocessor Thermal Monitoring: IEEE Transaction on VLSI, vol. 20 (2012), p.1590–1601.

DOI: 10.1109/tvlsi.2011.2161783

[8] T. A. Demassa, and Z. Ciccone, : Digital Integrated Circuits: John Wiley & Sons, Inc., (1996).

[9] Y. Tsividis, : Operation and Modeling of the MOS Transistor Second Edition: New York: McGraw-Hill, (1999).