Atmel Corporation

Atmel Rousset S.a.s.

Antoine Riviere

David Bernard

Frederic Demolli

Jean-Jacques Kazazian

A technique that minimizes false triggering of an electrostatic discharge (ESD) protection circuit is disclosed. In an embodiment, the resistor-capacitor (RC) time constant of an ESD trigger element is reduced during normal operation minimizing the risk of false triggering. Circuit layout area is saved without the need of a timeout circuit associated with releasing a device maintaining a trigger state (i.e., a trigger latch). A RC time constant for triggering is set in an operational context according to conditions of usage and desired application of the ESD protection circuit.

Method and apparatus for ESD protection

An electrostatic discharge protection circuit comprises a comparator coupled between a power supply terminal and ground. The comparator responds to an electrostatic discharge event producing a trigger signal at a comparator output. The comparator comprises a first and second current mirror. The first and second current mirrors each comprise a sense device and a mirror device. The mirror devices are coupled in series between the power supply terminal and ground. The first mirror device produces an incident current and the second mirror device receives an absorption current. With a supply voltage on the power supply terminal equal to or greater than a trigger supply voltage, the absorption current exceeds the incident current and produces a trigger signal at the comparator output. The trigger signal activates a shunt device that shunts current from the power supply terminal to ground.

Threshold voltage method and apparatus for ESD protection

An ESD protection circuit incorporates an ESD shunt device triggered by an ESD trigger network. In non-powered situations, a first RC time constant in the ESD trigger network, corresponds with the time range of the onset an ESD event and controls application of the ESD shunt device in response to the ESD event. A second RC time constant in a shunt trigger network is selected to be longer than the first RC time constant and holds-off triggering of a shunt device during ESD shunt protection. When activated during powered-on operation, the shunt device shunts a resistive element in the ESD trigger network forming a third time constant. The shunt device guards against false triggering during noise on a power rail by maintaining the third time constant in the ESD trigger network. The third time constant ensures that power rail voltage buildup due to noise dissipates before a false trigger develops.

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Pourcieux, France

Antoine Riviere