Melexis’ pressure sensors consist of a piezoresistive Wheatstone bridge that sits on the edge of a silicon membrane and transforms the stress induced by pressure on the membrane into an electrical signal. They can be used in conjunction with amplifier circuits to provide pressure indication. They may also be incorporated into a system in package (SIP), which integrates all the necessary circuitry, as in the Tire Pressure Monitoring sensor. The tire pressure monitor actually combines three sensor technologies in a single package: a pressure sensor; temperature sensor and a motion sensor.
Melexis manufactures highly sophisticate, fully integrated relative pressure sensors. These products incorporate the MEMs pressure sensor with signal processing and programmable gain and offset correction to enable a robust automotive grade pressure sensor. One use is in automotive vacuum boost systems to measure the air pressure in the vacuum chamber situated adjacent to a master brake cylinder. Depending on pressure variations during braking, a pump is activated and generates additional vacuum to increase braking force. Relative pressure sensors also have application in occupancy detection systems, where they are integrated into a car seat to turn the airbag system on or off; as well as in fuel vapour sensing, for emissions control.