Low-Voltage Current-Sensing CMOS Interface Circuit for Piezo-Resistive Pressure Sensor

  • Thanachayanont, Apinunt (Department of Electronic Engineering, Faculty of Engineering, King Mongkut's Institute of Technology Ladkrabang) ;
  • Sangtong, Suttisak (Department of Electronic Engineering, Faculty of Engineering, King Mongkut's Institute of Technology Ladkrabang)
  • Received : 2006.02.27
  • Published : 2007.02.28

Abstract

A new low-voltage CMOS interface circuit with digital output for piezo-resistive transducer is proposed. An input current sensing configuration is used to detect change in piezo-resistance due to applied pressure and to allow low-voltage circuit operation. A simple 1-bit first-order delta-sigma modulator is used to produce an output digital bitstream. The proposed interface circuit is realized in a 0.35 ${\mu}m$ CMOS technology and draws less than 200 ${\mu}A$ from a single 1.5 V power supply voltage. Simulation results show that the circuit can achieve an equivalent output resolution of 9.67 bits with less than 0.23% non-linearity error.