| 摘要 |
A motor-drive circuit comprising: a current-passage-control circuit to perform ON/OFF control of a drive transistor connected to a motor coil to pass current through the motor coil; an overcurrent-state-detection circuit to detect whether current passing through the drive transistor is in an overcurrent state where the current exceeds a predetermined threshold value; a charging and discharging circuit to start charging a capacitor in response to detecting the overcurrent state by the overcurrent-state-detection circuit and subsequently discharge the capacitor in response to not detecting the overcurrent state; and an overcurrent-protection-control circuit to stop the ON/OFF control to turn off the drive transistor, for an elapsed charging period for a charging voltage of the capacitor at a predetermined voltage to exceed a threshold voltage, and determine whether to perform such an overcurrent-protection-control as to turn off the drive transistor by detection of the overcurrent state, after the charging period has elapsed.
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