Patent ID: 7834662

Claim:
An apparatus comprising: a circuit supplied by a first supply voltage during use, the circuit having at least a first input signal; and a level shifter supplied by the first supply voltage during use and coupled to provide the first input signal to the circuit, wherein the level shifter is coupled to receive a plurality of second input signals, at least one of which is sourced from circuitry supplied by a second supply voltage during use, and wherein the level shifter comprises a plurality of transistors configured to generate the first input signal by logically combining the plurality of second input signals and level shifting to the first supply voltage, and wherein the level shifter comprises at least one additional transistor that is not required for functionality in the level shifter but rather is included to ensure symmetry in the level shifter by matching at least one of the plurality of transistors that is required for functionality, and wherein the additional transistor has a gate terminal tied to a static voltage during use.