| 摘要 |
PURPOSE:To prevent a breaking of a switching element by applying a high dV/dT and the like, by turning off the switching element when the power source voltage is less than a specific level and the operation in a controller is stopped, in a starting time or in a stopping time CONSTITUTION:A control voltage detector 6 stops the operation in a controller 5 to prevent an unstable operation of a microcomputer and the like in the controller 5 when the power source voltage of the controller 5 is less than a specific level in a starting time of in a stopping time, and turns off the output of a drive circuit 4 when the operation in the controller 5 is stopped. As a result, the input terminal of a switching element 2 can be turned off, and a breaking by applying a high dV/dT and the like can be prevented. Furthermore, a drive voltage detector 8 is provided, and by turning off the switching element 2 when the power source voltage of the drive circuit 4 is less than a specific value, the ON/OFF oscillation of the element 2 when the power source voltage is not sufficient is prevented, and a breaking of the element 2 owing to an excessive loss can be also prevented. |
