| 摘要 |
PURPOSE:To protect switching element from breakdown by supplying starting current through a differentiating circuit to the control electrode of a switching element while at the same time lowering the source voltage, i.e., the control circuit source voltage. CONSTITUTION:An inverter turns a switching element comprising a transistor(Tr) arranged between a DC power source E and a load circuit LC1 ON, OFF to supply power to the load circuit LC1. The starting circuit for the inverter supplies starting current to the base of the Tr1, where a resistor R0 and a source smoothing capacitor Co are connected in series with the DC power source E while a series circuit of a second resistor R1 and a first switch S1 is arranged in parallel and a series circuit of a third resistor R2, a capacitor C1 and a second switch S2 is connected to the base of the Tr1. Furthermore, a control circuit CR2 for the switches S1, S2 is provided and a start/stop circuit ST having priority to the control circuit CR2 is provided. By such arrangement, excessive starting current does not flow and the switching element can be protected from breakdown. |
