Novel PWM Based Readout Circuit for Pressure Sensors

In high-performance pressure measurement applications, to reduce the zero drift and sensitivity drift caused by thermal drift of silicon piezoresistive pressure sensors, temperature compensation is always necessary. A novel readout circuit suitable for temperature compensation has been proposed in this work. By deriving temperature information from pressure sensors itself, the additional temperature sensor for conventional temperature compensation is no longer required. Pressure and temperature information can be modulated onto a digital frequency signal through the readout circuit. Experimental results shows that pressure and temperature the sensor received have a good linear relationship with duty cycle and frequency of the output signal respectively. Temperature compensation can be carried out by demodulating the pressure and temperature information from the output signal. What' s more, the novel readout circuit has advantages of good noise immunity, low power consumption as well as suitable for long distance transmission.