Patent ID: 8072177
Filing Date: 2011-12-06
Classification: H02P,Y02P

Abstract:
1. A driver of a stepping motor, the driver comprising: an output unit for passing a load current to a driving coil of the stepping motor; a zero-cross detection unit for detecting a zero cross or near zero cross of the load current; an induced voltage detection unit for detecting an induced voltage of the driving coil when a zero cross or near zero cross of the load current is detected; and a determination unit for determining a state of a rotor of the stepping motor based on an induced voltage detected by the induced voltage detection unit, wherein the zero-cross detection unit includes a comparator for comparing an input signal to the output unit with an input threshold, and a signal delay unit for delaying a signal from the comparator, for detecting a zero cross or near zero cross of the load current by delaying the signal from the comparator through the signal delay unit.