Capacitive acceleration sensor for vehicle, has converter circuit with switch that is open in diagnosing operation mode, where periodic voltage in diagnosing operation mode is larger than periodic voltage in normal measuring operation mode

摘要

The sensor has a sensor unit (10) comprising a movable electrode and a fixed electrode, where a periodic voltage is supplied to the fixed electrode. A high voltage-generating circuit (23) applies a diagnosing voltage to an input side of a capacitance-voltage-converter circuit (21) for diagnosing an adherence of an external object between the electrodes. The converter circuit has a diagnosing switch that is open in a diagnosing operation mode, where the periodic voltage in the diagnosing operation mode is larger than the periodic voltage in a normal measuring operation mode. An independent claim is also included for a method for diagnosing of a sensor for a physical characteristic.