Apparatus and method for controlling auto gain of sensor, and sensor apparatus

The present invention relates to an automatic gain controlling device and method and a sensor device thereof. According to an embodiment of the present invention, the automatic gain controlling device for a sensor includes a PID controlling unit for generating and changing gain values in order to drive the peak value of a sensor signal outputted as a vibration output signal according to the movement or location of an object or external forces to a target value and for outputting a gain value-reflecting compensation sensor signal by controlling PIDs; and a margin calculating unit for deciding the level of changes in the peak values of the previous gain value-reflecting compensation sensor signal and the current gain value-reflecting compensation sensor signal and for calculating the margin at which the compensation sensor signal can be stabilized according to the determination result at the PID controlling performing stage. Provided are also a sensor device and an automatic gain controlling method for a sensor. [Reference numerals] (100) PID controlling unit; (300) Margin-calculating unit; (AA) Sensor signal