| 摘要 |
<P>PROBLEM TO BE SOLVED: To restrain a rise in power supply voltage caused by a regenerative current sourced to the power supply when a brake current flew in the drive coil, thereby preventing damage to the power supply or the withstand-voltage breakdown of an IC, etc. <P>SOLUTION: A motor drive circuit comprises: a detection circuit which detects a reverse current flowing from a first sink side transistor 14 to a second source side transistor 11 or from a second sink side transistor 13 to a first source side transistor 12; an override circuit which overrides the detection output of the detection circuit for a prescribed period from when the detection circuit started detecting a reverse current; a first inhibition circuit which, when the prescribed period has elapsed after the detection circuit started detecting a reverse current, inhibits synchronous rectification according to the detection output of the detection circuit; and a second inhibition circuit which, when each on-duty period of PWM signals switching the first or the second sink side transistor on is shorter than the prescribed period, inhibits synchronous rectification regardless of whether the first inhibition circuit is actuated or not. <P>COPYRIGHT: (C)2013,JPO&INPIT |
