Title :
Digital compensated capacitive pressure sensor using CMOS technology for low pressure measurements
Author :
Nagata, T. ; Terabe, H. ; Kuwahara, S. ; Sakurai, S. ; Tabata, O. ; Sugiyama, S. ; Esashi, M.
Author_Institution :
Toyoda Machine Works Ltd,., Aichi, Japan
Abstract :
A capacitive pressure sensor with digital output for low-pressure measurements has been fabricated using CMOS technology. The sensor output has been compensated and adjusted by a newly developed method. The sensor has the hybrid configuration of a sensor chip and a digital IC chip. The sensor chip consists of a sensor capacitor, a reference capacitor, and two capacitance-to-frequency converter circuits. The digital IC chip consists of a clock generator, a timing circuit, and a 12-b up/down counter. The thermal sensitivity shift and the thermal zero shift of the output were compensated at the sensor chip. The offset and full scale span of the output were compensated at the sensor chip. By using the novel compensation and adjustment technique, a thermal sensitivity shift of 0.026%F.S./ degrees C and a thermal zero shift of 0.013%F.S./ degrees C for a pressure range of 0-200 mmH/sub 2/O and a temperature range of 25-75 degrees C were obtained.<>
Keywords :
CMOS integrated circuits; compensation; digital integrated circuits; electric sensing devices; pressure transducers; switched capacitor networks; 25 to 70 degC; CMOS technology; capacitance-to-frequency converter circuits; capacitive pressure sensor; clock generator; digital IC chip; digital compensation; digital output; hybrid configuration; low pressure measurements; reference capacitor; sensor chip; thermal sensitivity shift; thermal zero shift; timing circuit; CMOS technology; Capacitance; Capacitive sensors; Capacitors; Clocks; Digital integrated circuits; Hybrid integrated circuits; Pressure measurement; Semiconductor device measurement; Timing;
Conference_Titel :
Solid-State Sensors and Actuators, 1991. Digest of Technical Papers, TRANSDUCERS '91., 1991 International Conference on
Conference_Location :
San Francisco, CA, USA
Print_ISBN :
0-87942-585-7
DOI :
10.1109/SENSOR.1991.148870
