Electrostatic discharge (esd) circuit capable of protecting internal circuit from being affected by esd zapping

Abstract

An ESD circuit includes a voltage division circuit, a RC control circuit and a voltage selection circuit. The voltage division circuit is connected between a first power pad and a first node, and generates a first voltage. The RC control circuit is connected between the first power pad and a second power pad, and generates a second voltage and a third voltage. The voltage selection circuit receives the first voltage and the second voltage, and outputs a fourth voltage. The first transistor and the second transistor are serially connected between the first power pad and the second power pad. A gate terminal of the first transistor receives the first voltage. A gate terminal of the second transistor receives the third voltage. The third transistor is connected with the first power pad and an internal circuit. A gate terminal of the third transistor receives the fourth voltage.