Sensor with thermal compensation network

摘要

A capacitive transducer (10) which provides an output voltage in response to the application of a mechanical stimulus such as pressure or acceleration includes a signal conditioning integrated circuit (12) to which are connected a variable capacitor (CVAR), a reference capacitor (CREF), a linear correction capacitor (CLIN) as well as an integrating capacitor (CINT) and associated filtering components. The linear correction capacitor (CLIN) is used to offset a fixed parasitic charge associated with the variable capacitor. Any net error charge appearing on a detect, common node (pin 4) between the variable capacitor and the reference capacitor is cancelled out by means of an analog feedback network (22). In a modified embodiment a thermal compensation network (40) allows for correction for thermal error at a second temperature without having any affect at a first temperature.