US Patent 7170321 Gate drive circuit with negative offset

A gate drive circuit capable of providing both positive and negative drive from a DC power supply is presented. The circuit includes an isolator stage, a driver stage, an optional tuning stage, an offset stage, a shaping stage, and a switching stage, each electrically coupled in the order described. The isolator stage provides electrical isolation from signal level circuitry. The driver stage boosts the power within the signal from the isolator stage. The tuning stage slows rising and falling edges along the signal from driver. The offset stage shifts the unipolar gate drive signal from the tuning stage into the negative voltage range. The shaping stage modifies the signal from the offset stage so as to ensure squared transitions. The switching stage enables voltage control. The described circuit is applicable to electronics utilizing a variety of voltage controlled switching devices.