Inertial force sensor and zero point correction method used therein

Abstract

A detecting unit outputs an object signal corresponding to an inertial force. A corrected signal is generated by correcting the object signal. A first environment value is obtained at a first time point. A second environment value is obtained at a second time point after the first time point. An environment difference value which is a difference between the first and second environment values is calculated. An environment change detection signal is output when an absolute value of the environment difference value is larger than a predetermined determination threshold. A first averaged signal is output by averaging a corrected signal in a predetermined period continuing to the first time point. A second averaging signal is output by averaging the corrected signal in a predetermined period continuing to the second time point. An offset difference value which is a difference between the first and second averaged signals is calculated. The offset difference value is stored when the environment change detection signal is output. The corrected signal is generated by adding the stored offset difference value to the object signal. This method can easily reduce the output offset even if an environment, such as an ambient temperature, abruptly changes.