Abstract: The invention discloses an ESD (Electro Static Discharge) protection circuit, including a resistor device, a capacitor device and a PMOS device. The resistor device is connected in series between a power supply and the capacitor device. The capacitor device is connected in series between the resistor device and the ground. A gate electrode of the PMOS device is connected between the resistor device and the capacitor device. A bulk electrode of the PMOS device is interconnected to a first electrode of the PMOS device, and the first electrode is connected to the power supply. Alternatively, another ESD protection circuit for multiple power supplies includes at least two aforementioned ESD protection circuits, and a common ESD bus. The ESD protection circuits are connected to separate power supplies, and both connected to the common ESD bus. By using the ESD protection circuit, there is no noise between the separate power supplies, and an ESD current could be discharged easily and safely.

Abstract: The present invention provides an IC ESD cell, which is applicable to multiple-power-input and mixed-voltage ICs and capable of maintaining power sequence independence of each power source. The ESD cell of the present invention comprises a voltage selector circuit, which connects two separate power sources to select the one having a higher potential as the output voltage. An NMOS is used to connect the two separate power sources. An RC circuit is connected to an output of the voltage selector circuit to distinguish ESD event from normal power source. Therefore, the channel of the NMOS will be conducted to let the ESD current be led out via a designed path, hence preventing internal circuits of an IC from damage and accomplishing the object of whole chip protection.

Abstract: The invention discloses an ESD (Electro Static Discharge) protection circuit, including a resistor device, a capacitor device and a PMOS device. The resistor device is connected in series between a power supply and the capacitor device. The capacitor device is connected in series between the resistor device and the ground. A gate electrode of the PMOS device is connected between the resistor device and the capacitor device. A bulk electrode of the PMOS device is interconnected to a first electrode of the PMOS device, and the first electrode is connected to the power supply. Alternatively, another ESD protection circuit for multiple power supplies includes at least two aforementioned ESD protection circuits, and a common ESD bus. The ESD protection circuits are connected to separate power supplies, and both connected to the common ESD bus. By using the ESD protection circuit, there is no noise between the separate power supplies, and an ESD current could be discharged easily and safely.

Abstract: The present invention provides an IC ESD cell, which is applicable to multiple-power-input and mixed-voltage ICs and capable of maintaining power sequence independence of each power source. The ESD cell of the present invention comprises a voltage selector circuit, which connects two separate power sources to select the one having a higher potential as the output voltage. An NMOS is used to connect the two separate power sources. An RC circuit is connected to an output of the voltage selector circuit to distinguish ESD event from normal power source. Therefore, the channel of the NMOS will be conducted to let the ESD current be led out via a designed path, hence preventing internal circuits of an IC from damage and accomplishing the object of whole chip protection.