Lucent Technologies Inc.

Other

At+t Corp.

At&t Ipm Corp.

Vijayan J Thottuvelil

Mark E Jacobs

Subhas Chandra Chalasani

Hengchun Mao

Yimin Jiang

Richard W Farrington

Kenneth J Timm

Robert J Kakalec

Rui Liu

Allen Frank Rozman

Jeffrey John Boylan

Roy Jaescentt Davis

Simon Fraidlin

Michael Clyde Steeves

Gabriel G Suranyi

Franklin F Makan

An impedance network for passive shoot-through protection of active switches in clamp-mode topologies. In one exemplary embodiment a switch-mode converter, includes: a primary switch; an auxiliary switch coupled in series with a capacitor; and an impedance network, coupled to the primary switch and the auxiliary switch; configured to limit current during simultaneous conduction of the primary and auxiliary switches. The impedance network includes a resistor coupled in series to a diode and both in parallel with an inductor. The impedance network permits the design of a clamp-mode converter without the need for a delay between switch turn-off and turn-on of primary and auxiliary switches.

Protection circuit for active switches in clamp-mode topologies, and power converter employing the same

A system and method for determining a capacity of a battery in a battery string that provides power to a load. In one embodiment, the system includes: (1) a power converter, having an input couplable across the battery and an output couplable across the battery string, that is adapted to transfer power from the battery to the load over a period of time and (2) a voltage sensor, associated with the power converter, that measures voltages of the battery during the period of time, wherein the voltages indicate the capacity of the battery.

Low dissipation system and method for determining battery capacity and battery plant incorporating the same

For use with a battery plant coupled to a source of electrical power and having a power bus coupled to a load, the battery plant including a battery string coupled across a pair of rails of said power bus, a battery management system, method of operation therefor and battery plant employing the same. In one embodiment, the battery management system includes a DC/DC converter, couplable in series with the battery string, adapted to condition a voltage provided to the battery string as a function of a characteristic of the battery string. The battery management system also includes a switching circuit, coupled across the DC/DC converter, adapted to selectively decouple the DC/DC converter from the battery string thereby allowing the battery string to power the load.

Battery management system, method of operation therefor and battery plant employing the same

For use with a power plant having a rectifier and a backup battery coupled to a variable load, a system for, and method of, assessing a capacity of the backup battery. In one embodiment, the system includes: (1) a controller, coupled to the rectifier, that controls an output current of the rectifier to maintain a discharge current of the backup battery at a substantially constant level and (2) a voltage sensor, coupled to the backup battery, that measures a voltage of the backup battery.

System and method for assessing a capacity of a backup battery and power plant incorporating the same

A bus holdup circuit for a module of a distributed power system, a method of bolstering bus voltage and a distributed power system employing the circuit or the method. In one embodiment, wherein the module has a backplane interface adapted to be removably coupled to a DC backplane of the distributed power system, the bus holdup circuit includes: (1) an energy storage circuit, coupled across the backplane interface, adapted to store and dissipate energy to bolster a voltage across the DC backplane and (2) an inrush limiting circuit, series-coupled to the energy storage circuit, adapted to limit an inrush current to the module.

Bus holdup circuit for a distributed power system and method of operation thereof

A power supply that provides a source of backup AC voltage and a method of operating thereof. In one embodiment, the power supply includes a transformer having main power and backup power windings and a secondary winding. The power supply also includes multiple stages, namely, (1) a primary power stage coupled to the main power winding, (2) a backup power stage coupled to the backup power winding and having a backup battery, one of the primary and backup power stages acting as a current fed source and (3) an AC power stage, coupled to the secondary winding, that provides a source of AC voltage. The power supply is operable in a normal mode of operation in which the primary power stage supplies power to the secondary winding and further supplies power to the backup power winding to allow the backup power stage to charge the backup battery. The power supply is also operable in a backup mode of operation in which the backup power stage transfers power from the backup battery to the secondary winding via the backup power winding.

Power supply providing backup AC voltage and method of operation thereof

An asymmetrical half-bridge power converter and a method of manufacturing the same. In one embodiment, the asymmetrical half-bridge power converter includes: (1) first and second power switches configured to be controlled by complementary drive signals having nominal first and second duty cycles of D and 1-D, respectively and (2) first and second capacitors, having intrinsic capacitance values proportional to 1-D and D, respectively, and intrinsic equivalent series resistance (ESR) values proportional to D and 1-D, respectively, configured to reduce input ripple current associated with the asymmetrical half-bridge power converter.

Asymmetrical half-bridge power converter having reduced input ripple and method of manufacturing the same

For use with a reserve battery couplable to a charging circuit capable of providing a charging current to the reserve battery, a mode selection circuit and a method of operation thereof. The mode selection circuit includes, in one embodiment, (1) a signal generator that generates a signal based on a temperature of the reserve battery and (2) a mode-changing circuit, coupled to the signal generator, that accepts the signal and selects an alternative one of: (a) a non-charge mode in which the charging current is substantially interrupted when the temperature is greater than a reference temperature and (b) a charge mode in which the charging current is provided to the reserve battery when the temperature is less than the reference temperature.

Mode selection circuit for a battery, a method of selecting modes for

A battery recharging circuit for a valve regulated lead-acid battery having a plurality of cells, each cell including a positive electrode, a negative electrode, a DC voltage source for generating a voltage applied to the positive and negative battery electrodes, and a reference electrode includes a regenerating voltage source for selectively applying a regenerating voltage between the reference electrode and one of the battery electrodes for regenerating the reference electrode, and a reference voltage source for generating a reference voltage. The circuit further includes circuitry for measuring the voltage level between the reference electrode and a battery electrode after removal of the regenerating voltage from the reference electrode. Circuitry compares the measured voltage level to the reference voltage to generate an error correction signal. The voltage generated by the DC voltage source is adjusted based upon the error correction signal, such that the voltage of the DC voltage source applied to the battery electrodes adjusts the voltage level between the reference electrode and one of the battery electrodes to be substantially equal to the reference voltage.

Recharging circuit and method for recharging a battery having a

For use with a flyback converter having a modulator for providing a main switch control signal thereto and main and cross-regulated output circuits, the cross-regulated output circuit subject to ringing and resulting voltage excursion, a voltage excursion controller and a method of operating the same. In one embodiment, the controller includes: (1) a delay circuit, coupled to the modulator, that generates a delay signal based on the main switch control signal and (2) an auxiliary switch, associated with the cross-regulated output circuit, that receives the delay signal and opens to isolate at least a portion of the ringing within said cross-regulated output circuit.

Multiple output flyback converter having improved cross-regulation and

For use with a switched-mode power converter having a modulator that develops a drive signal for a power switch, a compensation circuit, a method of compensating for a change in an output characteristic of the converter and a converter employing the circuit or the method. In one embodiment the compensation circuit includes (1) a sensor that senses the output characteristic and (2) a filter, coupled to the sensor, that develops an intermediate signal representing a change in the output characteristic. The modulator adjusts a switching period of the drive signal as a function of the intermediate signal thereby to decrease a reaction delay of the converter.

Compensation circuit method of operations thereof and converter

For use with a power converter having a power supply control circuit, a current startup bias circuit and a method of operating the same. In one embodiment, the circuit includes: (1) a charge reservoir that receives and stores a trickle current during a startup period of the power converter, a voltage of the charge reservoir increasing as the charge reservoir stores the trickle current and (2) a latch, coupled to the charge reservoir, that activates when the voltage reaches a threshold to couple the charge reservoir to the power supply control circuit and initiate operation thereof.

Low trickle current startup bias circuit and method of operation thereof

A controller for a power switch having an isolated control terminal and coupled to a secondary winding of a drive transformer and a method of preventing spurious turn-on of the power switch. The controller includes: (1) a controllable switch, coupled between the secondary winding and the power switch, that alters a control voltage of the power switch in response to a characteristic of the secondary winding, and (2) a bias circuit coupled to the controllable switch and the power switch that provides a voltage differential between the controllable switch and the power switch to prevent spurious turn-on thereof.

Controller for a power switch and method of operation thereof

Mode selection circuit for a battery and method of operation thereof

A power supply and method of operation thereof. In one embodiment, the power supply includes: (1) a primary side power switch, (2) an isolation transformer having a primary winding coupled to the primary side power switch, the primary side power switch conducting intermittently to transfer current from an input of the power supply to the isolation transformer, (3) a secondary side power switch, coupled to a secondary winding of the isolation transformer, that is operable to conduct within a conduction period of the primary side power switch to transfer current from the isolation transformer to an output of the power supply, a portion of the current being contained within the power supply during a nonconduction period of the secondary side power switch and (4) a capacitor, coupled to the secondary side power switch, that, circulates the portion toward the output during the nonconduction period.

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Plano, TX, United States of America

Vijayan J Thottuvelil