1. Field
This disclosure relates generally to level shifters used in integrated circuits, especially ones requiring significantly higher voltages than are used by the normal logic transistors.
2. Related Art
Non-volatile memories (NVMs) typically require higher voltages than the power supply used for the logic transistors. The logic transistors can be made differently, typically by increasing the thickness of the gate dielectric and extending the gate length, to provide some extension of the voltage they can use for logic operations. This increase in voltage capability is typically not enough though so level shifters are required. Level shifters can have sensitivities to the process used to make the transistors that form the level shifters. If process variations are greater than anticipated or process changes result in somewhat different operating characteristics, there may be difficulties with an existing design.
Accordingly there is a need to provide further improvement in achieving level shifters that function well over a broad range of processes.