Patent ID: 10608520

Abstract:
A switch circuit includes a first switch connected to a first node such that the first switch is connected in series between the first node and a first electrode terminal of a DC power source. a second switch connected in series between the first node and a second node which is configured to be connected to a second electrode terminal of the DC power source, a soft switch circuit, a power switching element, and a controller. The soft switch circuit includes a capacitor connected in series between a third node and one of the first and second nodes, a charge-discharge switch connected in series between the third node and another of the first and second nodes, and a charge-discharge resistor connected in parallel to the charge-discharge switch. The power switching element has a drain terminal, a gate terminal connected to the first node, and a source terminal connected to the second node. The controller turns off the first switch, turns off the second switch, and switches the charge-discharge switch from turning off of the charge-discharge to turning on of the charge-discharge at a time point when the controller detects that a current flowing across the drain terminal and the source terminal of the power switching element is equal to or larger than a predetermined threshold while the first switch is turned on.