Patent ID: 7808286

Claim:
Circuitry in a driver circuit having a driver circuit input and a driver circuit output, comprising: a first voltage rail which provides the driver circuit output, the driver circuit output providing a supply voltage to the circuitry; a second voltage rail; a first pre-driver transistor having a control electrode, a first current electrode coupled to the first voltage rail, and a second current electrode; a power transistor having a control electrode coupled to the second current electrode of the first pre-driver transistor, a first current electrode coupled to the first voltage rail, and a second current electrode coupled to the driver circuit input; comparison circuitry coupled to the first voltage rail which indicates when a voltage level of the first voltage rail is above or below a reference voltage level; a level shift circuit coupled between the first voltage rail and the second voltage rail which provides a level shifted output; a tapered buffer circuit coupled to the first voltage rail and to a first circuit node, wherein the tapered buffer circuit receives the level shifted output and provides a buffered output to the control electrode of the first pre-driver transistor; and a rail voltage adjusting circuit coupled between the first circuit node and the second voltage rail, which, in response to the comparison circuitry indicating that the voltage level of the first voltage rail is above the reference voltage level, adjusts a voltage level of the second voltage rail.