US Patent 7595667 Drive circuit

A drive circuit has a level shift circuit which outputs level-shifted on and off signals each for controlling a power semiconductor element in an on or off state, a first RS flip flop which is supplied with the on signal through a setting input terminal and supplied with the off signal through a resetting input terminal, and which outputs a drive signal to the power semiconductor element, and a logic filter circuit which is provided between the level shift circuit and the first RS flip flop, and which blocks transmission of the on and off signals during the time period from a time at which both the on and off signals become a first logic to a time at which both the on and off signal become a second logic.