Title :
A temperature sensor based on a thermal oscillator
Author :
Makinwa, K.A.A. ; Witte, J.F.
Author_Institution :
DIMES, Delft Univ. of Technol.
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;
Conference_Titel :
Sensors, 2005 IEEE
Conference_Location :
Irvine, CA
Print_ISBN :
0-7803-9056-3
DOI :
10.1109/ICSENS.2005.1597908
