A CMOS Temperature Sensor Circuit

Takashi OHZONE  Tatsuaki SADAMOTO  Takayuki MORISHITA  Kiyotaka KOMOKU  Toshihiro MATSUDA  Hideyuki IWATA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E90-C   No.4   pp.895-902
Publication Date: 2007/04/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e90-c.4.895
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Integrated Electronics
Keyword: 
CMOS,  temperature sensor,  temperature dependent voltage,  subthreshold current,  

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Summary: 
A supply voltage (VDD) independent temperature sensor circuit, which can be realized by the optimum combination of three current modes of n-MOSFETs including the subthreshold current using the feedback scheme from the temperature dependent voltage (VTD) output to the gates of three n-MOSFETs, was proposed and fabricated by a standard 1.2 µm n-well CMOS process. The circuit consists of only 17 MOSFETs without high resistors resulting in a small die area of 0.18 mm2. The temperature coefficient TC of the sensor circuit can be controlled by the channel length ratio L4/L3 of two n-MOSFETs. The average temperature sensor voltage VTS and its typical TC are 1.77 V at VDD=5.0 V (20) and 5.1 mV/ for VDD=5.01.0 V in the temperature range of -20-100 in case of L4/L3=9, respectively.