Patent ID: 7233468

Claim:
A level shifter ESD protection circuit, being used to receive a first signal and to output a second signal with the corresponding level according to the level of the first signal, wherein the first signal operates between a first system voltage and a first ground voltage, and the second signal operates between a second system voltage and a second ground voltage, the level shifter ESD protection circuit comprises: an inverter receiving the first signal and outputting a first inverted signal, wherein the first inverted signal is the inverse of the first signal, and the first inverted signal operates between the first system voltage and the first ground voltage; a first switch, the first end of the first switch being connected to the output end of the inverter to receive the first inverted signal, so as to determine the connection status between its first end and the second end according to the level of the second system voltage; a second switch, the first end of the second switch receiving the first signal to determine the connection status between the first end and the second end of the switch according to the level of the second system voltage; a voltage level shifting circuit, its first input end being connected to the second end of the first switch, the second input end of the voltage level shifting circuit being connected to the second end of the second switch, the output end of the voltage level shifting circuit outputting the second signal; a first ESD clamp circuit, its first connecting end being connected to the second system voltage, its second connecting end being connected to the first input end of the voltage level shifting circuit; and a second ESD clamp circuit, its first connecting end being connected to the second system voltage, its second connecting end being connected to the second input end of the voltage level shifting circuit.