TW270230B - Electrostatic discharge protection device - Google Patents

Abstract

A capacitor coupled electrostatic discharge protection device, that is installed between one input pad and one internal circuit, or between one output pad and one output buffer, comprises: one first connection end connecting between the input pad and the internal circuit; one second connection connecting between the output pad, the internal circuit and the output buffer; ESD protection circuit connecting to the first and second connection ends, that could bypass the ESD current, and via the processing of one capacitor-coupled device and one potential clamped element, in order to protect the internal circuit and the output buffer from damage by the ESD current; It features that when the ESD voltage is in one first or fourth signal state, by coupling appropriate voltage level to the ESD protection circuit or the output buffer the capacitor coupled device could effectively lower either snapback breakdown voltage of the ESD protection circuit or the output buffer, and when the ESD voltage is in one second or third signal state, the potential clamped element could make ESD voltage of the first or second connection end maintain one low voltage level.