Teccor Electronics, LP

Littelfuse, Inc.

Littlefuse, Inc.

Kelly C Casey

Elmer Lee Turner, Jr

Dennis M McCoy

Darren J Daugherty

Dimitris Jim Pelegris

Chad A Vos

A protection circuit employing a pair of SCR devices connected respectfully from telephone line tip conductor and ring conductors to ground. The SCR devices are of the type providing internal semiconductor resistors between the gate and cathode terminals for sensing overcurrents in the telephone line conductors, and providing voltage sensitive semiconductor regions so that the SCR devices are sensitive to overvoltages on the telephone line conductors. A pair of diodes are connected across the cathode-anode terminals of the SCR devices to provide overvoltage protection for positive polarity overvoltages on the telephone line.

SCR circuit for protecting central office end of telephone line

A low capacitance overvoltage protection circuit () provides protection to a communication line (). A diode bridge () is connected to the communication line () so that overvoltages of both polarities pass through an overvoltage protection device () in one direction. A bias voltage supplyapplies a bias voltage across a semiconductor overvoltage protection device () through isolation resistors () to make the capacitance of the device () independent of changes in communication line voltages. When line voltages exceed the magnitude of the bias voltage, a blocking diode () prevents current from flowing through the bias voltage supply () in a reverse direction.

Linear low capacitance overvoltage protection circuit using a blocking diode

A bipolar semiconductor overvoltage protection circuit presents less capacitance to a communication line. The overvoltage protection circuit includes an overvoltage protection device that is biased with a voltage to not only reduce the capacitance thereof, but also to reduce the change in capacitance as a function of frequency. Changes in communication line voltages thus change the capacitance of the overvoltage protection device less, resulting in the ability to allow the transmission of high capacity data protocols with reduced error rates.

Linear low capacitance overvoltage protection circuit

An overvoltage protection circuit for protecting low voltage, high speed digital communication lines. The circuit is integrated into a semiconductor chip and includes a diode bridge, a transient voltage suppressor (TVS) device and resistors through which a bias voltage can be applied to the TVS device to reduce the capacitance hereof.

Integrated circuit providing overvoltage protection for low voltage lines

A semiconductor thyristor device that incorporates buried region breakdown junctions laterally offset from an emitter region. By spacing the buried regions around the emitter region, current carriers emitted from the buried regions are distributed over a large area of the emitter region, thereby providing a high current capability during initial turn on of the device. In order to achieve low breakover voltage devices, the buried regions are characterized with high impurity concentrations, with the breakdown junctions located near the surface of the chip. The low voltage thyristor device minimizes the area of high dopant concentration junctions, thus minimizing the chip capacitance and permitting high speed, low voltage signal operation.

Semiconductor device for low voltage protection with low capacitance

A thyristor provides overcurrent protection to a low impedance load, such as a transformer, by adding a resistance in series with the transformer winding. As overcurrents attempt to pass through the transformer winding, a sufficient voltage is generated in the transformer so that a thyristor connected thereacross is triggered into conduction. A resistance formed between the thyristor gate and cathode establishes the threshold of current that can pass through the transformer winding before the thyristor is triggered. When triggered into conduction, the thyristor shunts the current and the transformer is thus protected.

Thyristor circuit providing overcurrent protection to a low impedance load

A semiconductor thyristor device incorporates buried regions to achieve low breakover voltage devices, and the buried regions are offset laterally with respect to the emitter regions. The low voltage thyristor devices can be incorporated into five-pin protection modules for protecting customer circuits.

Low voltage protection module

A semiconductor thyristor device that incorporates buried regions centrally located on the chip with respect to the other semiconductor regions. By centering an upper and lower buried region, larger-area contacts can be realized, thereby increasing the current capability of the device. In order to achieve low breakover voltage devices, the buried regions are offset laterally with respect to the respective emitter regions. The low voltage thyristor devices can be incorporated into five-pin protection modules for protecting customer circuits.

Very low voltage actuated thyristor with centrally-located offset buried region

A connector block formed in a semiconductor chip to provide all contacts on the same side of the chip. The connector block is preferably formed by driving a slow diffusing dopant deep into the chip from both sides until the diffused dopant overlaps in the middle of the chip. The connector block is metalized with a top contact and connected to circuits. The bottom of the connector block is metallized and connected to other bottom side contacts which, in turn may be connected to circuits. This arrangement effectively allows all contacts to be available from the top side of the semiconductor chip.

Single side contacts for a semiconductor device

An integrated circuit ( ) providing overvoltage and overcurrent protection to a line ( ). The integrated circuit ( ) is constructed to provide overvoltage protection when a voltage exceeding a specified magnitude is impressed across the cathode and anode terminals ( ), irrespective of the gate-cathode current. A gate terminal ( ) is provided to trigger the overvoltage protection device into conduction when a gate current exceeding a predefined value is carried on the line ( ). The gate-cathode structure of the integrated circuit ( ) includes a semiconductor resistance ( ) which functions to make the gate current required for turn on higher, thereby allowing the gate-cathode terminals ( ) of the integrated circuit ( ) too be connected in series with the line ( ) to be protected.

Semiconductor device providing overvoltage and overcurrent protection for a line

A telephone line protection element constructed of three lead frames having contact fingers for holding therebetween a semiconductor cell providing overvoltage protection between the telephone line and the customer circuits. The lead frames are soldered to a resistive semiconductor material to provide a fail-safe mechanism that mechanically connects either the tip or ring telephone line conductors to ground if a sufficient overcurrent exists. In response to an overcurrent, the resistive semiconductor material generates heat and melts the solder in contact therewith, which allows a pre-bent member of the lead frame to move in contact with a ground terminal, thereby shunting the overcurrent to ground. The entire protection element includes very few components and is efficiently assembled and attached to the pins of a 5-pin module.

Primary telephone line protector with fail safe

A telephone line protection module having a printed circuit board base with conductive paths connected to pins of the module. Overvoltage sensitive semiconductor devices are soldered to the ends of a conductive bridge, and the bridge is spring-biased between a module cover and the conductive bridge. The semiconductor devices are thus forced into electrical contact with the printed circuit paths. In addition, in the event the semiconductor devices are thermally destroyed, the conductive bridge is forced by the spring into direct contact with the printed circuit paths.

Growing community of inventors

Flower Mound, TX, United States of America

Kelly C Casey