Patent ID: 8817436

Claim:
An electrostatic discharge protection device, comprising: a clamp unit, providing a discharging path from a first power line to a first ground line; and a control circuit, receiving a first power voltage from the first power line and a second power voltage from a second power line, wherein the control circuit comprises a trigger unit and a latching unit, when the first power voltage and the second power voltage are applied, the trigger unit generates a first control signal and the latching unit generates an isolation signal to disconnect the discharging path, and when the first power voltage and the second power voltage are not applied, the trigger unit generates a second control signal according to an electrostatic signal from the first power line and the latching unit generates a trigger signal to turn on the discharging path, wherein the latching unit comprises: a first p-type transistor, comprising a source electrically connected to the first power line, and a drain for generating the isolation signal or the trigger signal; a first inverter, comprising an input terminal electrically connected to the drain of the first p-type transistor, and an output terminal only connected to a gate of the first p-type transistor; and a first n-type transistor, comprising a source electrically connected to the first ground line, a drain electrically connected to the drain of the first p-type transistor, and a gate only connected to the trigger unit and for receiving the first control signal or the second control signal, wherein the trigger unit comprises: a second p-type transistor, comprising a source electrically connected to the first power line, and a gate electrically connected to the second power line; a resistor, comprising a first end electrically connected to the drain of the second p-type transistor, and a second end electrically connected to the first ground line; and a second inverter, comprising an input terminal electrically connected to the first end of the resistor, and an output terminal for outputting the first control signal or the second control signal.