| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress a surge voltage or noise in a voltage driven power semiconductor device compatibly with suppression of a switching loss in simple circuit configuration.SOLUTION: At a time point t2 when a switching MOSFET 4 is turned on during a turn-on operation of a power semiconductor device Q1, a resistance value of gate resistance of the power semiconductor device Q1 is switched from a resistance value of a first gate resistor Rg1 to a lower resistance value of parallel resistance of the first gate resistor Rg1 and a third gate resistor Rg3. Thus, in a first half of the turn-on operation, a switching speed of the power semiconductor device Q1 is suppressed low and in a latter half of the turn-on operation, the switching speed of the power semiconductor device Q1 is accelerated. At such a time, the gate resistors are switched after the lapse of a period in which a sharp current change S occurs, after a delay time of a delay circuit 3 from start of turn-on in such a manner that the switching speed of the power semiconductor device Q1 during the period in which the sharp current change S occurs, is decelerated.</p> |
