Patent ID: 9300207
Filing Date: 2016-03-29
CPC Classification: H02M,H03K

Claim Text:
1. A switching control circuit comprising: a voltage applier that applies a first voltage to a gate of a power device in a first period and applies a second voltage, that is higher than the first voltage, to the gate of the power device in a second period, the first period starting when the power device is switched from off to on, the second period starting after the first period has elapsed and ending when the power device is turned off; a current detector that detects whether a current flowing through the power device exceeds a threshold; and a voltage decreaser that decreases a gate voltage, which is applied to the gate of the power device, with a first speed if the current detector detects that the current flowing through the power device exceeds the threshold in a second detection period, and decreases the gate voltage with a second speed, which is lower than the first speed, if the current detector detects that the current flowing through the power device exceeds the threshold in a third detection period, the second detection period starting after a first detection period has elapsed, the first detection period starting from the time the power device is switched from off to on, the third detection period starting after the second detection period has elapsed, wherein in the first detection period, the power decreaser does not decrease the gate voltage of the power device even if the current detector detects that the current flowing through the power device exceeds the threshold, and the first detection period ends after the gate voltage of the power device reaches the first voltage.