Lucent Technologies Inc.

Ranco Inc. of Delaware

Ranco Electronics Division

At+t Corp.

Ranco Inc.

Richard R Garcia

Jimmie D Gillett

Royal H Sites

Charles B Ingram

Rui Liu

Gabriel G Suranyi

Pradhuman S Zaveri

Various systems and methods for providing soft-start and soft-stop to an asymmetrical half-bridge converter and a power supply employing such systems or methods. The power supply includes a power train including an asymmetrical half-bridge converter having an energy storage device coupled across a complementary switch thereof. In one embodiment, a conductive path is coupled across the energy storage device to substantially discharge the energy storage device and thereby reduce current stress in the complementary switch when the converter turns on. In another embodiment, a controller, coupled to the complementary switch, provides a drive waveform to drive the complementary switch. The controller increases a duty cycle of the drive waveform as the converter turns off.

System and method for reducing transient switch currents in an

For use in a module, a redundancy detection circuit for, and method of, determining whether a predetermined adequate redundancy exists when the module is present in a system. In one embodiment, the module includes: (1) a sensor, associated with the module, that receives a signal that is a function of a number of modules present in the system and (2) a calculation circuit, coupled to the sensor, that determines from the signal whether a surplus capacity of the module provides at least the predetermined adequate redundancy for the system.

Decentralized redundancy detection circuit and method of operation

A control circuit for, and method of, alternately controlling one of at least two controllable characteristics of a controlled circuit. The circuit includes: (1) a first control subcircuit having a first error amplifier for developing a first control signal as a function of a first controllable characteristic of the controlled circuit, (2) a second control subcircuit for developing a second control signal as a function of a second controllable characteristic of the controlled circuit, (3) an OR circuit for selecting which of the first control signal and the second control signal is to control the controlled circuit and (4) an overshoot limiting circuit for establishing a feedback loop around the first error amplifier as a function of a voltage present in the OR circuit while the second control signal controls the controlled circuit, the feedback loop preventing a saturation of the first error amplifier and thereby reducing a slew rate time delay when the first control signal is selected to control the controlled circuit.

System and method for limiting overshoot in a voltage and current

A switching boost type voltage regulator includes a resonant snubber network connected in parallel with its FET power switch. The snubber includes a FET auxiliary switch that is connected and turned on in order to reduce the voltage across the FET power switch to a zero level at its turn-on transition. A driver circuit, driven by a voltage regulating pulse width modulation (PWM) pulse, initially turns on the FET auxiliary switch to reduce a voltage across the FET power switch and then turns on the FET power switch when the voltage across drops below a threshold level. The FET auxiliary switch is turned off when the FET power switch is turned on. A latch circuit insures the complimentary states of these two switches. The snubber circuit is disabled a near to zero voltage regardless of line and load levels and hence the power dissipation in the snubber is significantly reduced.

Modulated snubber driver for active snubber network

A compressor drive system that includes a thermostat producing a signal indicating the measured air temperature, a modulation control circuit connected to the thermostat to produce a motor drive signal from the temperature signal and which is output to a motor drive switching bridge circuit. The motor drive switching bridge circuit is connected to a rectifier that converts single phase alternating current to direct current. The switching bridge uses the motor drive signal from the modulation control circuit and the rectifier output to produce multiphase power including a speed control signal imposed on the power for regulating speed. A motor connected to drive a compressor is included. The motor is powered by the motor drive switching bridge circuit multiphase power output. The speed of the motor is controlled as a function of the temperature signal.

Compressor drive system

A temperature sensor. Two thick films resistor elements are mounted to a substrate and then a thermistor coupled to those elements to form a voltage divider. The resistance of the thermistor is determined at a reference temperature and the thick film resistor elements are precisely trimmed using a laser trimming system to produce a precision voltage divider. To sense temperatures the voltage divider is energized and its resistance ratio is sensed utilizing a bridge circuit.

Temperature sensing apparatus and method of making same

A temperature sensor. Two thick film resistor elements are mounted to a substrate and then a thermistor coupled to those elments to form a voltage divider. The resistance of the thermistor is determined at a reference temperature and the thick film resistor elements are precisely trimmed using a laser trimming system to produce a precision voltage divider. To sense temperatures the voltage divider is energized and its resistance ratio is sensed utilizing a bridge circuit.

An air conditioner clutch control device includes a resistive type temperature sensor, connected to power dividers for providing a threshold voltage and a trigger voltage for first and second comparators. Resistor type power dividers provide first and second reference voltages to the comparators. Logic circuits are attached to the comparators for providing first and second state signals. Thus, when the temperature exceeds the first reference the first state is produced to turn on the air conditioner; when the temperature falls below the second reference, the second state is produced to turn off the air conditioner. A zener diode is provided to protect the logic circuits from transients in the battery source of power and from a reversal in polarity. A coil of a relay switch is operated by the first and second states to close a switch to energize a coil of a relay switch of an air conditioner's compressor. The coil of the relay switch protects the logic circuits from self-induced transients and a diode protects the logic circuits from excess positive voltage. The coil of the relay switch of the air conditioner is, for positive switching, connected permanently to ground and the positive end is switched and for negative switching, connected permanently to the battery source of power and the negative end is switched.

Growing community of inventors

Plano, TX, United States of America

Richard R Garcia