A 0.7 v relative temperature sensor with a non-calibrated ±1 °c 3σ relative inaccuracy

Li Lu, Bozorgmehr Vosooghi, Liang Dai, Changzhi Li

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Abstract

This paper presents a new low-voltage relative temperature sensor for multi-core digital processor on-chip thermal management in a 180 nm CMOS process. Three types of sensing diodes including Schottky barrier diode (SBD), subthreshold MOSFET diode and dynamic threshold MOSFET (DTMOS) diode have been investigated for low-voltage operation, while traditional parasitic PNP-bipolar junction transistor (BJT) diodes are implemented to provide a performance reference. A matrix of 7 × 7 small remote sensor nodes is implemented on the chip with a deployment density of 49/0.81 mm2 and sharing the same bias current generator, control logic, and data converter. The measured minimum supply voltage (not including the clock control block) of the sensor is 0.7 V over-55° to 125 °C. The relative sensing inaccuracies (3σ) without calibration are less than 1.5 °C, 1.2 °C and 1 °C for the designs based on SBD, subthreshold MOSFET, and DTMOS, respectively. To the best of the authors' knowledge, this is the first time that non-calibrated relative sensing accuracy is reported for SBD-based and DTMOS-based temperature sensors, and the best reported result for the design based on subthreshold MOSFET. The absolute inaccuracies with calibration-per-chip are also presented. Furthermore, the multi-location thermal monitoring function has been experimentally demonstrated and a 1.8 on-chip temperature gradient was detected.

Original languageEnglish
Article number07272773
Pages (from-to)2434-2444
Number of pages11
JournalIEEE Transactions on Circuits and Systems I: Regular Papers
Volume62
Issue number10
DOIs
StatePublished - Oct 1 2015

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Keywords

  • Dynamic threshold MOSFET
  • Low-voltage
  • Multilocation thermal monitoring
  • Relative accuracy
  • Schottky barrier diode
  • Subthreshold MOSFET
  • Temperature sensor

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