| 摘要 |
PROBLEM TO BE SOLVED: To provide a drive apparatus for a stepping motor wherein current control can be carried out according to an actual load torque to prevent step-out and vibration without a sensor for detecting the position or speed of a stepping motor shaft. SOLUTION: The drive apparatus for a stepping motor includes current detecting portions 201, 202 which detect a current value of phase current flowing through each phase winding, a constant-current-controlling portion 300 which constant-current-controls the phase current flowing through each phase winding, zero crossing detecting portions 102a, 102b which detect a zero cross of each phase current based on the detection result of each current detecting portion, a period measuring portion 104 which detects a period between edges on the basis of the edges of a drive control pulse signal, a phase difference detecting portion 105 which detects a phase difference between the edge of the drive control pulse signal and the zero cross detected by the zero crossing detecting portion, and a control device 106 which causes the constant-current-controlling portion to perform constant-current control with a current value according to the phase difference ratio which is the ratio of the phase difference to the period between edges and the drive frequency of the stepping motor. COPYRIGHT: (C)2011,JPO&INPIT |
