Texas Instruments Corporation

Pravin N Popat

Diethard Unterweger

Ronald J Candelet

Gennady Baskin

Gary L Tonnies

A surge protection device to protect telecommunication equipment coupled to telephone lines is shown having in a first embodiment three cells with each cell having a semiconductor element with a reverse breakdown PN junction mounted on a heat sink. The device includes a lead frame having a first pair of leads formed with a platform raised out of the plane of the remainder of the lead frame to provide suitable clearance relative to the semiconducting elements and each platform has a finger extending downwardly into engagement with a top electrode of a respective semiconducting element and is soldered thereto. A second lead lies in the plane of the lead frame and is soldered to a first heat sink plate mounting two semiconducting elements and another finger extending from one of the platforms is soldered to a second heat sink plate mounting the third semiconducting element. The heat sinks, semiconducting elements and portions of the leads are encapsulated in thermally conductive, electrically insulative epoxy. The device, when subjected to excessive current and voltage conditions, is adapted to fail closed. A second embodiment has two cells mounted on a single heat sink plate mounted in the same manner as in the first embodiment.

Telecommunication equipment protector

A surge protection system has a surge protection device comprising a semiconducting disc element disposed between two electrodes. The element is operable to selectively conduct electrical energy between the electrodes in providing a first level of surge protection for the circuit, and the electrodes are adapted to move toward each other to maintain a short circuit condition between the electrodes in the event the element is destroyed in providing a second relatively greater level of surge protection. The semiconducting element provides a critical energy conduction path between a selected limited portion of one side of the element and the other element side along which destruction of the element preferentially occurs due to overheating in providing the second level of surge protection. One electrode has a selected limited post portion disposed in electrical engagement with said selected limited portion of said one element side to facilitate establishment and maintenance of the short circuit condition between the electrodes in providing the second level of surge protection.

Surge protection device and system

A simplified solid state transient voltage and overcurrent protector for telecommunications equipment providing uniform protection characteristics between telephone lines and between either line and ground is shown in which two symmetrical thyristor chips are mounted with their normal common layer connected together on an enlarged heat sink. The assembly, together with current limiting PTC elements is encapsulated to form a dual-in-line package.

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Norton, MA, United States of America

Pravin N Popat