| 摘要 |
PROBLEM TO BE SOLVED: To provide a motor drive device that is able to fix time required to return to a normal energization pattern after the detection of excess current.SOLUTION: A control microcomputer 7 exerts on/off control for FETs Q1 to Q4 on the basis of a fixed PWM control period. When a current value detected by a resistance element 13 inserted in a power source line reaches or exceeds a limit value, the microcomputer 7 turns off the FET Q1 or Q3 composing an inverter circuit 5. Alternatively, the FET Q2 or Q4 that has the same arm as the semiconductor switching element on the positive side of the FET Q1 or Q3 turned off, is turned on only for the time in which dead time is subtracted from the PWM control period. When time corresponding to the PWM control period has passed thereafter, an energization pattern before a current value not lower than the limit value is detected is returned. |
