Patent ID: 7859216

Claim:
A stepper motor apparatus, including: a stepper motor rotating in response to a driving signal, a duty cycle of which is modulated, supplied thereto in order to drive a pointer; a stopper configured to stop rotation of the stepper motor mechanically in cases where a driven member associated with the stepper motor is in abutment therewith; an initialization driving device configured to feed the driving signal into the stepper motor in order to drive the stepper motor to rotate in a backward direction where the driven member is driven toward the stopper; a detection coil producing an induced voltage by means of rotation of the stepper motor; a position detection device configured to determine whether the driven member is in abutment with the stopper or not by examining the induced voltage on the detection coil; a first stopping device configured to stop rotation of the stepper motor in the backward direction by maintaining driving signal's phase at which the abutment is detected by the position detection device; and a normal driving device configured to feed the driving signal into the stepper motor in order to drive the stepper motor to rotate in a direction where the pointer homes in on its commanded position, after first stop by the first stopping device, characterized by further including: a memory configured to store a predetermined phase; a forward driving device configured to feed the driving signal into the stepper motor in order to drive the stepper motor to rotate in a forward direction where the driven member is driven against the stopper, after first stop by the first stopping device; and a second stopping device configured to stop rotation of the stepper motor in the forward direction by maintaining the predetermined phase when the driving signal transmitted by the forward driving device arrives at the predetermined phase, wherein the normal driving device drives the stepper motor to rotate again after second stop by the second stopping device.