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EP0549320A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Method and apparatus for ESD protection

Assignee: Texas Instruments Inc
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Filing: 1992-12-22
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Granted: —
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Expires: 2012-12-22
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Abstract

Abstract Method and apparatus are provided for ESD protection of integrated circuits. The method employs dynamic gate coupling effects to achieve uniform conduction and provide much improved ESD protection for integrated circuits. The apparatus of the present invention consist of an NMOS device whose gate is connected to the drain of a field oxide device. The sources of the NMOS and the field oxide devices are connected to ground, while the drain of the NMOS and gate of the field oxide device are connected to a signal terminal. In addition, preferably an N-well resistor is connected between the gate of the NMOS device and ground. The operation of the apparatus of the present invention is involved with simultaneous MOS/bipolar conduction and offers higher ESD protection level than a grounded gate NMOS circuit.

Inventors

  • 👤 Charvaka Duvvury

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-08 13:06
CPC Classifications
H; H10; H10D; H10D89/00; H10D89/60; H10D89/601; H10D89/811; H10D89/813; H10D89/814; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/0302; H01F1/0306

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 74 words
An NMOS ESD circuit, comprising: a thin oxide transistor, having its drain-to-source path connected between a signal terminal and a reference voltage supply and having a gate, and a high threshold transistor, having a threshold voltage greater than a preselected power supply voltage, having its drain connected to the gate of said first thin oxide transistor, having its source connected to said reference voltage supply, and having its gate connected to said signal terminal.
Claim 2
Dependent Claim 25 words
The ESD circuit of Claim 1, further comprising an N-well resistor connected between said reference voltage supply and said gate of said thin oxide transistor.
Claim 3
Dependent Claim 19 words
The ESD circuit of Claim 1 or Claim 2, wherein said high threshold transistor comprises a field oxide transistor.
Claim 4
Dependent Claim 19 words
The ESD circuit of any preceding claim, wherein said signal terminal is an output terminal of an output buffer.
Claim 5
Dependent Claim 16 words
The ESD circuit of any preceding claim, wherein said signal terminal is an input signal terminal.
Claim 6
Dependent Claim 16 words
The ESD circuit of any preceding claim, wherein said signal terminal is a voltage reference line.
Claim 7
Dependent Claim 16 words
The ESD circuit of any preceding claim for an integrated circuit formed in a semiconductor body.
Claim 8
Independent Claim 71 words
A method for ESD protection of an integrated circuit, comprising: capacitively coupling the voltage from an ESD event to the gate of an NMOS device, using said capacitively coupled voltage to turn-on said NMOS device, discharging said voltage from said ESD event to a reference voltage supply through said turned on NMOS device, and discharging said capacitively coupled voltage on said gate of said NMOS device to said reference voltage supply.
Claim 9
Independent Claim 69 words
A method for ESD protection, comprising: applying a capacitively coupled voltage from an ESD event to provide a first trigger, discharging the voltage of said ESD event to a reference voltage supply responsive to said first trigger, applying a portion of the voltage of said ESD event to provide a second trigger, and discharging said applied capacitively coupled voltage to said reference voltage supply responsive to said second trigger.

References Cited (Backward Citations)

US3746946A Cited
EP0055552A2 Cited
US4605980A Cited
EP0257774A1 Cited
US4855620A Cited
US4829350A Cited
WO1990010952A1 Cited
FR2652449A1 Cited

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