US 6,618,230 B2 · Electrostatic discharge cell of integrated circuit

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.

Claims10

Dependent claims

An electrostatic discharge protection cell for protecting multiple power input and mixed-voltage integrated circuits from damage by an electrostatic discharge event, the electrostatic discharge protection cell comprising:

a voltage selector circuit coupled to at least two separate power sources for selectively coupling an output terminal thereof to one of said separate power sources being at the highest electric potential;
an RC circuit characterized by a predetermined time constant and coupled to said output terminal of said voltage selector circuit, said RC circuit including an output node for providing a switch-driving signal upon detection of the electrostatic discharge event;
and
an MOS switch coupled to said output node of said RC circuit for shunting two of said at least two power sources responsive to said switch-driving signal.

1 more element

Dependencies are inferred from the claim text.

Electrostatic discharge cell of integrated circuit

Life of this patent

Electrostatic discharge cell of integrated circuit

Life of this patent

Abstract

Claims10