Patent ID: 8335135
Filing Date: 2012-12-18
Classification: G04C,H02P

Abstract:
1. A stepping motor control circuit comprising: a rotation detecting unit configured to detect an induced signal generated by a rotation of a rotor of a stepping motor and detect the state of rotation of the stepping motor depending on whether or not the induced signal exceeds a predetermined reference threshold voltage in a predetermined detecting segment; and a control unit configured to control the driving of the stepping motor by any one of a plurality of main driving pulses having energies different from each other or a correction driving pulse having larger energy than the respective main driving pulse according to a result of detection by the rotation detecting unit, wherein the detection segment is divided into a first segment immediately after the drive with the main driving pulse, a second segment after the first segment, and a third segment after the second segment, the first segment is a segment for determining the state of rotation of the rotor in a second quadrant, and the second segment and the third segment are segments for determining the state of rotation of the rotor in a third quadrant in a state in which the increment of the load is smaller than a normal load, and the control unit changes the main driving pulse to a main driving pulse having larger energy when the rotation detecting unit does not detect the induced signal exceeding the reference threshold voltage in at least one of the first segment and the third segment, but detects in the second segment.