Patent ID: 6946813
Filing Date: 2005-09-20
Classification: H02P

Abstract:
1. A step motor control device for controlling operation of a step motor, the step motor control device comprising: first and second switch elements connected to each other in series; third and fourth switch elements connected to each other in series; a coil of a step motor, the coil being connected between a node of the first and second switch elements and a node of the third and fourth switch elements; a first series circuit having a first detection element and a fifth switch element connected in parallel with the first switch element; a second series circuit having a second detection element and a sixth switch element connected in parallel with the third switch element; control means for controlling an on/off operation of the first to fourth switch elements in response to a supplied drive pulse to allow a current to flow in the coil to rotationally drive the step motor, and for controlling an on/off operation of the third, fourth, fifth and sixth switch elements in response to a rotation detection control pulse supplied during a rotation detection period immediately after the rotational drive of the step motor in accordance with the supplied drive pulse is completed; and detecting means for detecting the presence/absence of the rotation of the step motor in accordance with a comparison result obtained by comparing a threshold voltage with a voltage generated between the coil and the first detection element of the first series circuit and with a voltage generated between the coil and the second detection element of the second series circuit.