Patent ID: 7656627

Claim:
An electrostatic discharge (ESD) protection circuit, comprising: a first discharging component, coupled between an input/output pad and a first power line of an IC; a second discharging component, coupled between the input/output pad and a second power line of the IC; a first diode coupled between the input/output pad and a first ESD bus in a forward direction toward the first ESD bus; a second diode coupled between the first ESD bus and the second power line in a forward direction toward the first ESD bus; a third diode coupled between the input/output pad and a second ESD bus in a forward direction toward the input/output pad; a fourth diode coupled between the second ESD bus and the first power line in a forward direction toward the first power line; and an ESD detection circuit, comprising: a capacitor and a resistor formed in series, and coupled between the first power line and the second power line; a first triggering component, having a first positive power end coupled to the first ESD bus and a first negative power end coupled to the first power line; a first input of the first triggering component being coupled to a node between the capacitor and the resistor; and a second triggering component, having a second positive power end coupled to the second power line and a second negative power end coupled to the second ESD bus, a second input of the second triggering component being coupled to the node between the capacitor and the resistor; wherein the first and the second discharging components are turned off during normal power operations; the first discharging component is triggered by a first output of the first triggering component in a first ESD event, and the second discharging component is triggered by a second output of the second triggering component in a second ESD event.