Integrated circuit input/output ESD protection circuit with gate voltage regulation and parasitic zener and junction diode
First Claim
1. An electro-static discharge protection circuit adapted for use in an integrated circuit comprising:
- a first protective field effect transistor connected between a pad of said integrated circuit and a potential of said integrated circuit and having a gate, said first transistor responsive to a voltage applied to said gate to control a current through said first transistor; and
a voltage regulator connected between said gate of said first protective transistor and said potential of said IC, said diode voltage regulator operative to apply said voltage to said gate such that a desired amount of current flows through said first transistor when an electro-static discharge is applied to said pad.
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Accused Products
Abstract
An integrated circuit structure with input/output gate voltage regulation and parasitic zener and junction diodes for protection against damage resulting from electrostatic discharge (ESD) events. The circuit includes a first protective FET connected between an input/output pad and a ground potential of the integrated circuit. A diode voltage regulator is also connected between the gate of the first protective FET and a reference potential of the integrated circuit. The first protective FET receives a voltage from its gate-drain overlap capacitance during an ESD event. The diode is operative during an ESD event to provide a sufficient voltage to the first FET gate to permit a desired ESD current flow through the first protective FET. In one embodiment the first FET is an NMOS device and the diode voltage regulator is a series of p-n forward biased diodes.
29 Citations
11 Claims
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1. An electro-static discharge protection circuit adapted for use in an integrated circuit comprising:
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a first protective field effect transistor connected between a pad of said integrated circuit and a potential of said integrated circuit and having a gate, said first transistor responsive to a voltage applied to said gate to control a current through said first transistor; and a voltage regulator connected between said gate of said first protective transistor and said potential of said IC, said diode voltage regulator operative to apply said voltage to said gate such that a desired amount of current flows through said first transistor when an electro-static discharge is applied to said pad. - View Dependent Claims (2, 3, 4, 5)
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6. A method for performing electrostatic discharge protection in an integrated circuit, comprising:
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connecting a first protective field effect transistor between a pad of the integrated circuit and a potential of said integrated circuit, said first transistor being responsive to a voltage applied to said gate thereby controlling a current through said first transistor; connecting a voltage regulator between said gate of said first protective transistor and said potential of said integrated circuit, said voltage regulator having the ability to apply said voltage to said gate such that a predetermined amount of current flows through said first transistor when an electrostatic discharge is applied to said pad; wherein said potential is a ground potential and said first protective transistor is an NMOS field effect transistor having a drain electrically connected to said ground potential. - View Dependent Claims (7, 8)
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9. An electrostatic discharge circuit adapted for use in an integrated circuit, comprising:
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a first protective field effect transistor connected between a pad of said integrated circuit and a potential of said integrated circuit and having a gate, said first transistor responsive to a voltage applied to said gate to control a current through said first transistor; a voltage regulator connected between said gate of said first protective transistor and said potential of said integrated circuit, said voltage regulator operative to apply said voltage to said gate such that a predetermined amount of current flows through said first transistor when an electrostatic discharge is applied to said pad; and a second protective field effect transistor having a gate electrically connected to said pad and said drain of said first protective transistor, a drain connected to said gate of said first transistor, and a source connected to said ground potential of said integrated circuit. - View Dependent Claims (10, 11)
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Specification