Marconi Communications Gmbh

Reliance Comm/tec Corporation

Reltec Corporation

William I Chen

Mahlon Danny Kimbrough

Philip L Dillon

Edwin Glenn Yancey

Glenn Yancey

A four quadrant power conversion topology comprising a multi-winding inductor, four switches, and four diodes is disclosed. The four quadrant power conversion is utilized in a number of power conversion devices such as a power efficient non-linear power amplifier that comprises the 4Q power conversion topology of the present invention and a switch-control-signal generator coupled to the 4Q power conversion topology. The switch-control-signal generator generates switch activation signals for driving the four switches of the 4Q power conversion topology. In one embodiment the switch-control-signal generator comprises a polarity detector for detecting the polarity of an input signal, a full wave rectifier for rectifying the input signal, a pulse width modulator which produces a pulse width modulated signal representative of the full wave rectified input signal, and steering logic that generates switch activation signals for driving the power conversion topology to produce an output representative of the input signal. The amplifier may optionally include switch drivers to condition the switch activation signals to drive the switches in the 4Q power conversion topology.

Four quadrant power conversion topology

A line feed circuit employing a low-inductance transformer, and providing a major portion of the terminating impedance as line feed resistors connected between a telephone line and the transformer primary. A low impedance output amplifier drives a low resistance transformer secondary, thus reducing the need for large transformer inductances. By connecting the line feed resistors between the transformer and the telephone line, high voltage surges are absorbed by the resistors, and thus little is dissipated in the transformer. The transformer can be made physically small, because of the reduced inductance, reduced winding insulation, and reduced power requirements. The resistance forward type of line feed circuit lends itself well to simple implementation with flux cancellation and impedance synthesis circuits.

Resistance forward telephone line feed circuit

A circuit for increasing the apparent inductance presented by a transformer to a differential signal. The circuit may be used in a battery feed interface circuit for providing battery power to a subscriber's telephone or in a current sink interface circuit for providing a low impedance DC loop closure toward a telephone line feed circuit while maintaining a high impedance for differential AC signals. In either usage the inductance multiplier circuit always multiplies the primary inductance of the transformer by a factor which is one plus a positive number. The transformer has three windings. The multiplication is accomplished by a current source which provides to the third winding a current which flows therein in a manner so as to oppose the current flowing in that winding due to the voltage induced in that winding when the first and second windings are excited by the differential AC signal.

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Bedford, TX, United States of America

William I Chen