How to Integrate an Absolute Pressure Sensor into Circuit?

With so many different pressure sensing technologies available, there is no single way to integrate a sensor into your circuit. In most cases, you will be looking to connect your absolute pressure sensor to a microcontroller.

Some sensors are so simple they require a significant amount of circuitry to condition the signal for use with a microcontroller. A pressure sensor that simply provides access to a wheatstone bridge circuit will require significant amplification to deliver an output large enough for a typical microcontroller’s analog-to-digital converter (ADC) to measure.

A quad op-amp configuration as shown in the diagram below provides an example for such an amplification circuit. Such circuitry needs to be carefully designed and may also require proper screening and low-noise design techniques to guarantee a reliable output signal.

Due to process variation and component tolerances, your circuit may also need individual calibration for each circuit board you produce. Temperature compensation may also need to be considered. Sensors with digital outputs are much easier to connect to a microcontroller. These will include all the signal conditioning, amplification and temperature compensation. The measurements are then converted into a digital value and stored in an internal register.

A sensor with a digital interface may not meet your needs if you need to measure rapid variations in pressure. An SPI or I2C interface only supports a certain number of data transfers per second. With more than one device on the bus, the available bandwidth drops with the increase of devices hanging on the bus.

For measurement of pressure that varies quickly, it is likely that you will need to invest time in the development of your own analog front-end, coupled with an analog-to-digital converter with a suitable conversion time.

Our company provides more product information to help you to choose your right sensor.

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