US Patent 7446564 Level shifter

A level shifter is disclosed, which has an input control circuit, a high-level voltage supply and a step-down circuit. The high-level voltage supply provides a high-level voltage source. The step-down circuit is coupled between the input control circuit and the high-level voltage supply circuit, and includes a high-level control device and a low-level control device. The high-level control device can provide a step-down function for protecting the low-level control device. The low-level control device is control to switch by the control signal or the inverted control signal, thereby driving the high-level voltage source to output.