A temperature sensor based on a thermal oscillator

Author

Makinwa, K.A.A. ; Witte, J.F.

Author_Institution

DIMES, Delft Univ. of Technol.

fYear

2005

fDate

Oct. 30 2005-Nov. 3 2005

Abstract

In this paper, a temperature sensor based on the thermal diffusion constant of silicon is presented. It consists of an oscillator whose frequency is determined by the phase-shift of a thermal filter. The filter consists of two heaters and a thermopile implemented in the substrate of a standard CMOS chip. In the thermal domain, this filter has a low-pass characteristic, whose phase shift is determined solely by its physical dimensions and by the thermal diffusion constant of silicon. Since the latter is temperature dependent and essentially process independent, the oscillator´s frequency can be used as a well-defined, microprocessor-compatible, measure of temperature. Measurements on 8 samples show that the sensor´s inaccuracy is less than plusmn2degC over the temperature range -50degC to 125degC

Keywords

CMOS integrated circuits; frequency locked loops; low-pass filters; silicon; temperature measurement; temperature sensors; thermal diffusion; thermopiles; voltage-controlled oscillators; -50 to 125 C; CMOS chip; Si; low pass filters; phase shift; temperature measure; temperature sensor; thermal diffusion constant; thermal filter; thermal oscillator; thermopiles; Choppers; Frequency measurement; Low pass filters; Semiconductor device measurement; Silicon; Temperature dependence; Temperature distribution; Temperature measurement; Temperature sensors; Voltage-controlled oscillators;

fLanguage

English

Publisher

ieee

Conference_Titel

Sensors, 2005 IEEE

Conference_Location

Irvine, CA

Print_ISBN

0-7803-9056-3

Type

conf

DOI

10.1109/ICSENS.2005.1597908

Filename

1597908