Patent ID: 9525374
Filing Date: 2016-12-20
CPC Classification: H02P

Claim Text:
1. A motor driving circuit for driving a step motor, comprising: a logical circuit synchronized with a step pulse signal to control a bridge circuit connected to a coil of the step motor and control electric power supplied to the coil of the step motor; a counter electromotive force detecting unit configured to detect a counter electromotive force generated between both ends of the coil; and a step-out predicting unit comprising: wherein the step-out predicting unit is configured to assert the detection signal indicating a sign of step-out of the step motor, when the counter electromotive force detected at a detection time is lower than the threshold voltage, is the detection time being after a lapse of a time, that is calculated by multiplying a predetermined coefficient to a length of a high impedance period of the coil, from transition to the high impedance period.