Sensor failure or abnormality detecting system incorporated in a physical or dynamic quantity detecting apparatus

摘要

A reference voltage generating circuit (11) is constituted by resistors (RE) and (RF) each having a resistance not influenced by an application of pressure. The reference voltage generating circuit (11) is connected between one and the other ends of a bridge circuit. A failure judgement of the bridge circuit is performed based on a comparison of a voltage difference (V BC ) between two midpoints (B, C) of the bridge circuit and voltage differences (V CE , V BE ) between a reference voltage level of the reference voltage generating circuit (11) and the voltage levels of two midpoints (B, C).