US Patent 7609090 High speed level shifter

Embodiments of the present invention provide level shifter circuits capable of high frequency operations. The level shifter circuit utilizes a dynamic charge injection device, which diminishes a capacitive coupling effect between a gate and a drain of input NMOS devices, when the input signal switches from a high logic level to a low logic level. The dynamic charge injection device is incorporated at output nodes to provide initial thrust to the level shifter circuits, which triggers a positive regenerative feedback of cross-coupled pull up PMOS devices enabling a rapid transition and hence the high frequency operation.