Stepping motor drive device and method

The reference signal generation unit 110 a integrates, in the integration circuit 3 , a staircase signal generated by the staircase generation unit 2 , and thereby generates a reference signal VCTA whose signal level changes continuously over time, and which represents a limit value for the supply current. According to the control of the PWM control unit 120 a, the bridge rectification circuit 130 a maintains the coil supply current at the limit value, using a current chopper method. Additionally, when the current supply is stopped, the bridge rectification circuit 130 a performs synchronous rectification, where the transistors 10 and 12 are brought into conduction, and a regenerative current is circulated in a closed circuit formed with the coil 19 a. When the reference signal VCTA decreases relatively fast, the synchronous rectification prohibition unit 115 a prohibits one of the transistors 10 and 12 from being brought into conduction when the current supply is stopped.