Active ESD protection circuit with blocking diode
AssigneeTexas Instruments Incorporated
InventorsMuhammad Yusuf Ali, Rajkumar Sankaralingam
Life of this patent
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Abstract
An electrostatic discharge (ESD) protection integrated circuit (IC) includes a substrate having a semiconductor surface, a high power supply rail (VDD) and a low power supply rail (VSS) on the semiconductor surface. A trigger circuit including at least one trigger input and at least one trigger output is coupled between VDD and VSS. An active shunt including at least a large MOSFET is coupled between VDD and VSS. The trigger output is coupled to a gate electrode of the large MOSFET, and at least one diode or diode connected transistor (blocking diode) is coupled between VDD and the trigger circuit, within the trigger circuit or between the trigger output and gate electrode.
Claims14
An electrostatic discharge (ESD) protection circuit, comprising:
- a voltage supply rail;
- a blocking diode having a first terminal connected directly to the voltage supply rail and a second terminal free of being connected to the voltage supply rail;
- a functional circuitry including an input/output (IO) pad;
- an IO trigger circuit connecting to the IO pad and independent of the voltage supply rail;
- a trigger circuit including:
- a first trigger input connected to the IO pad via the IO trigger circuit, a second trigger input connected to the second terminal of the blocking diode, and a trigger output;
- and
- a shunt transistor including:
- a current electrode coupled to the voltage supply rail, and a control electrode coupled to the trigger output.
An ESD protected integrated circuit (IC), comprising:
- a first supply rail;
- a second supply rail;
- a first trigger circuit having a first input coupled to the first supply rail and a first output free from direct connecting to the first and second supply rails;
- a second trigger circuit having a second input coupled to the second supply rail and a second output free from direct connecting to the first and second supply rails;
- a blocking diode coupled to the first and second outputs of the first and second trigger circuits, the blocking diode having a cathode and an anode free from connecting to the first and second supply rails;
- and
- a shunt transistor including a first current electrode coupled to the first supply rail, a second current electrode coupled to the second supply rail, and a control electrode coupled to the cathode of the blocking diode.
Dependencies are inferred from the claim text.