| 摘要 |
PURPOSE:To prevent the damage to a semiconductor module device at the time of power interruption by reducing the capacitor capacitance of an upper arm of a power source supply unit from that of a lower arm. CONSTITUTION:A semiconductor module device comprises a control IC 11 for controlling an AC output at the output terminal of a transistor(Tr) in an inverter 9 for driving a motor 18, an upper arm (UP) 14 for supplying power to the IC 11, and a T-arm (DW) 17. Particularly, the capacitance of smoothing capacitors 25a-26c of the UP 14 and the capacitance of smoothing capacitors 27a-27c of a DW 17 are 1:2. the falling speed of the power source voltage is regulated. The current of the UP 14 flowing to Trs 7a, 7b and the current of the DW 17 are divided by a time difference to prevent the flow of a large current at once, thereby suppressing control elements 10a, 10b to become impossible to be controlled and hence preventing the flow of overcurrents to the Trs 7a, 7b. |
