US 7,889,469 B2Granted

Electrostatic discharge protection circuit for protecting semiconductor device

AssigneeKabushiki Kaisha Toshiba

InventorKentaro Watanabe

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Abstract

A discharge circuit holds the potential difference between a power supply terminal and reference potential terminal at a predetermined value. The gates of a first pMOSFET and first nMOSFET are connected to an input terminal. A second pMOSFET is connected between the first pMOSFET and power supply terminal, and has a gate to which a first signal is supplied. A second nMOSFET is connected between the first nMOSFET and reference potential terminal, and has a gate to which a second signal is supplied. A detection circuit outputs the first signal which turns on the second pMOSFET and the second signal which turns on the second nMOSFET, while the potential difference is held at the predetermined value. The detection circuit outputs the first signal which turns off the second pMOSFET and the second signal which turns off the second nMOSFET, while the potential difference deviates from the predetermined value.

Claims20

Dependent claims

An electrostatic discharge (ESD) protection circuit comprising:

a first power supply potential terminal to which a first power supply potential is applied;
a reference potential terminal to which a reference potential is applied;
an input terminal provided between the first power supply potential terminal and the reference potential terminal;
a discharge circuit which holds a potential difference between the first power supply potential terminal and the reference potential terminal at a predetermined value;
a first p-type MOSFET having a gate connected to the input terminal;
a first n-type MOSFET having a gate connected to the input terminal;
a second n-type MOSFET connected between the first n-type MOSFET and the reference potential terminal, and having a gate to which a first control signal is supplied;
and
a detection circuit connected between the first power supply potential terminal and the reference potential terminal, the detection circuit outputting the first control signal which turns on the second n-type MOSFET while the potential difference between the first power supply potential terminal and the reference potential terminals is held at the predetermined value, and outputting the first control signal which turns off the second n-type MOSFET while the potential difference between the first power supply potential terminal and the reference potential terminal deviates from the predetermined value.

6 more elements

An electrostatic discharge (ESD) protection circuit comprising:

a first power supply potential terminal to which a first power supply potential is applied;
a reference potential terminal to which a reference potential is applied;
an output terminal provided between the first power supply potential terminal and the reference potential terminal;
a discharge circuit which holds a potential difference between the first power supply potential terminal and the reference potential terminal at a predetermined value by discharging an overcurrent applied to one of the first power supply potential terminal and the reference potential terminal;
a first p-type MOSFET having a gate to which a first signal is supplied;
a first n-type MOSFET having a gate to which a second signal is supplied;
a second n-type MOSFET connected between the first n-type MOSFET and the reference potential terminal, and having a gate to which a second control signal is supplied;
and
a detection circuit connected between the first power supply potential terminal and the reference potential terminal, the detection circuit outputting the first control signal which turns on the second n-type MOSFET while the potential difference between the first power supply potential terminal and the reference potential terminals is held at the predetermined value, and outputting the first control signal which turns off the second n-type MOSFET while the potential difference between the first power supply potential terminal and the reference potential terminal deviates from the predetermined value.

6 more elements

Dependencies are inferred from the claim text.