Driving circuit for power semiconductor element including controlling circuit that provides control when detected voltage reaches predetermined voltage

摘要

Provided is a driving circuit which suppresses a surge voltage at the time of switching a power semiconductor element and reduces switching loss. An element (10) such as an IGBT and another element (20) to be paired are connected, the element (10) is driven by a driver (22), and a gate voltage is controlled by a control circuit (24). When the power semiconductor element is turned off, a comparator (26) detects that a voltage (Vak) of the element (20) is a prescribed voltage, the control circuit (24) switches gate resistance from low resistance to high resistance to suppress the surge voltage, and the switching loss is reduced. When the power semiconductor element is turned on, start up of the voltage (Vak) is detected, and the control circuit (24) switches the gate resistance from high resistance to low resistance after a prescribed time to suppress the surge voltage, and the switching loss is reduced.