Title :
A high-accuracy digital readout technique for humidity sensor
Author :
Shi, Xiaojing ; Matsumoto, Hiroki ; Murao, Kenji
Author_Institution :
Fac. of Eng., Miyazaki Univ., Japan
fDate :
10/1/2001 12:00:00 AM
Abstract :
A high-accuracy digital readout technique of capacitance difference for a capacitive-type humidity sensor is presented. Based on the sigma-delta (EA) technique, the structure detects the relative humidity by providing a digital readout of capacitance change it causes. Analysis shows that the structure is insensitive to circuit imperfections, thus permitting the realization of digital readout with good accuracy. A resolution as high as 20 bits is achievable. Simulation results are given to confirm the effectiveness
Keywords :
capacitive sensors; digital readout; humidity sensors; integrating circuits; sigma-delta modulation; switched capacitor networks; PSPICE; calibration scheme; capacitance change; capacitance difference; capacitive-type humidity sensor; comparator; feedback; high resolution; high-accuracy digital readout; parasitic capacitances; polyimide capacitor; quantizer; relative humidity; sigma-delta technique; switched-capacitor integrator; thermal noise effects; Capacitive sensors; Capacitors; Circuit simulation; Electronics industry; Helium; Humidity control; Industrial electronics; Operational amplifiers; Parasitic capacitance; Temperature sensors;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
