Title :
A low voltage mixed signal ASIC for digital clinical thermometer
Author :
Wokhlu, Atul ; Krishna, R. Vipin ; Agarwal, Sandeep
Author_Institution :
Arcus Technol. Ltd., Bangalore, India
Abstract :
This paper describes a mixed signal, low voltage, digital clinical thermometer chip. Temperature is sensed using a thermistor sensor. A modified Schmitt trigger based relaxation oscillator is used to convert thermistor resistance into a frequency signal. A ROM is used to map the Schmitt trigger frequency onto temperature. An extensive analysis of various errors in temperature measurement is provided. The chip can measure temperature to an accuracy of better than 0.1°C down to 1.1 V battery voltage. It has a die size of 87×91 mils and is implemented in a 1.2 μm double metal single poly CMOS process
Keywords :
CMOS integrated circuits; biomedical electronics; biomedical measurement; digital instrumentation; measurement errors; mixed analogue-digital integrated circuits; relaxation oscillators; sensitivity analysis; temperature measurement; thermistors; thermometers; trigger circuits; 1.1 V; 1.2 micron; 32 to 42 C; LV mixed signal ASIC; ROM; Schmitt trigger based relaxation oscillator; digital clinical thermometer; double metal single poly CMOS process; frequency signal; low voltage operation; modified Schmitt trigger; temperature measurement errors; thermistor sensor; thermometer chip; Application specific integrated circuits; Frequency conversion; Low voltage; Oscillators; Temperature measurement; Temperature sensors; Thermal resistance; Thermal sensors; Thermistors; Trigger circuits;
Conference_Titel :
VLSI Design, 1998. Proceedings., 1998 Eleventh International Conference on
Conference_Location :
Chennai
Print_ISBN :
0-8186-8224-8
DOI :
10.1109/ICVD.1998.646643
