| 摘要 |
A switch driving circuit electrically opens and closes a switch circuit (5) including two N-channel type semiconductor switching elements (6a, 6b) series connected in opposite directions, thereby electrically opening and closing an electrical path between a DC power supply (4) and an inverter circuit (1). The switch driving circuit (38) has a reference potential point in common with the inverter circuit (1) and supplies an opening/closing control signal to the switch circuit (5). The switch driving circuit (38) includes a half bridge circuit including two semiconductor switching elements (10, 11) series connected between a driving power supply and the reference potential point. Two protection diodes (13, 14) are connected in parallel to the semiconductor switching elements (10, 11) respectively. At least one current blocking diode (39, 42, 43) is configured to block current from flowing from the reference potential point through the diode (39, 42, 43) to the switch circuit (5) side when the DC power supply (4) is connected to the inverter circuit (1) in reverse polarity. |
