Lucent Technologies Inc.

Agere Systems Inc.

Gary H Weiss

Malcolm Harold Smith

Ronald Lamar Freyman

Bruce W McNeill

Yehuda Smooha

Charles Raymond Miller

David W Thompson

Sandeep Pant

Protection is provided against electrical surges resulting from Electrical Over Stress conditions, e.g., when interfacing circuits with powered connections. An EOS shunt is activated for as long as the EOS condition exists. EOS protection using an EOS shunt in accordance with the principles of the present invention remains activated by a voltage threshold trigger as long as necessary. In a disclosed embodiment, an EOS shunt includes a voltage threshold detector that detects a voltage on a power bus with respect to a ground rail exceeding a predetermined amount, e.g., 5 volts in a device powered at 3.3 volts. During the EOS event, a path between power and ground comprising a transistor is turned on.

Electrical over stress robustness

An integrated circuit includes topological features for weakening or otherwise modifying a blowable fuse in order to decrease the current needed to blow the fuse. This allows a decrease in the size of the circuit components which are needed to supply the current for blowing the fuse, in turn allowing compaction of the layout of the circuitry needed to blow the fuse. To this end, topological features are used to deform the shape of or otherwise modify the fuse, in turn increasing the resistance of the fuse or introducing flaws that allow the fuse to blow at a lower current.

Using topological features to lower the blowing current needed for fuses

Blowable fuses on an integrated circuit are programmed in software, responsive to the control of an addressable memory which communicates with the peripheral data bus of a digital processor to allow increased flexibility of the programming operation, and to allow for correction both during the manufacturing process and after packaging of the manufactured integrated circuit. In a preferred embodiment, the fuses are operated (i.e., blown) responsive to transistor switching elements present on the integrated circuit and which are controlled by the addressable memory. The switching elements, and the associated fuses, can be accessed through software in similar fashion to any other peripheral device. The preferred addressable memory includes an instruction register and a data register, which are loaded from and write to the peripheral data bus. Internally, the data register includes an array of registers corresponding to the fuse links with which the system is associated. Data words in the registers are written from or read to the data register tinder the control of instructions in the instruction register, and the fuses are then blown serially, by reference to the data in the registers.

Software programmable write-once fuse memory

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Slatington, PA, United States of America

Gary H Weiss