Patent ID: 7420393

Claim:
A level shifter for interfacing a first circuit operating at a first voltage higher than a ground voltage with a second circuit operating at a second voltage higher than the first voltage, comprising: a first inverter coupled between the second voltage and the first voltage; a second inverter coupled between the second voltage and the first voltage, the second inverter being cross-coupled with the first inverter for latching a value therein; a first switch module comprising a PMOS transistor having a source coupled to the first inverter and a gate coupled to the first voltage via a first resistor to reduce a voltage difference between the gate and the source of the PMOS transistor, and an NMOS transistor having a source coupled to an input signal and a drain coupled to the PMOS transistor; and a second switch module coupled between a data storage node of the first and second inverters and an inverted input signal swinging between the ground voltage and the first voltage, wherein the first and second inverters and the first and second switch modules include one or more MOS transistors with gate oxide layers of the same thickness.