TW270229B - Electrostatic discharge protecting circuit for SCR - Google Patents

Abstract

An electrostatic discharge protecting circuit, that is applicable to integrated circuit, and installs one wire between internal circuit and buffer pad to avoid the buffer pad influenced by electrostatic discharge so as to destroy the internal circuit, and is coupled between one reference high voltage and one reference low voltage, comprises: one first low voltage gate trigger SCR, in which the first low voltage gate trigger SCR consists of one anode, one anode gate, one cathode, one cathode gate and one gate trigger, and the cathode gate floating, the anode and the anode gate coupled to the reference high voltage, the cathode coupled to the wire; one second low voltage gate trigger SCR, in which the second low voltage gate trigger SCR consists of one anode, one anode gate, one cathode, one cathode gate and one gate trigger, and the anode coupled to the reference high voltage, the cathode and the cathode gate coupled to the reference low voltage, the anode coupled to the wire; one third low voltage gate trigger SCR, in which the third low voltage gate trigger SCR consists of one anode, one anode gate, one cathode, one cathode gate and one gate trigger, and the cathode gate floating, the anode coupled to the reference low voltage, the anode gate coupled to the reference high voltage, the cathode coupled to the wire; one current-limiting resistor with one end coupled to the buffer pad, with the other end coupled to gate trigger of the first low voltage trigger SCR, gate trigger of the second low voltage gate trigger SCR, and gate trigger of the third low voltage gate trigger SCR.