Abstract:
An active circuit for delivering three phase AC input power received from a three phase rectifier to a boost converter and a method of operating the same. In one embodiment, the active circuit includes a phase selection switching circuit, coupled to the rectifier, that selects an inner phase of the three phase AC input power. The active circuit also includes a switching network, coupled to the phase selection switching circuit and the rectifier, that controls a current waveshape of the inner phase and a current waveshape of at least one other phase, thereby to reduce harmonics associated with three phase AC input current.
Abstract:
For use with a boost converter having first, second and third input inductors, a switching network, method of reducing input current total harmonic distortion (THD) associated with the boost converter, and boost converter employing the switching network and method. In one embodiment, the switching network includes first and second switches coupled between corresponding rails of the boost converter. The switching network also includes first, second and third L-C resonant networks wye-coupled to a node located between the first and second switches and coupled to the first, second and third input inductors, respectively. The first and second switches and the first, second and third L-C resonant networks cooperate to create resonant voltages across, and induce phase currents through, the first, second and third input inductors to reduce input current THD associated with the boost converter.
Abstract:
A boost converter for converting an input voltage received at an input thereof into first and second output voltages provided at first and second outputs thereof, respectively, and a method of operating the boost converter. In one embodiment, the boost converter includes: (1) a first switching circuit coupled to a first rail of the input and having a first switch and a first capacitor coupled in parallel, (2) a second switching circuit coupled to a second rail of the input and having a second switch and a second capacitor coupled in parallel, (3) a contactor, coupled between the first and second switching circuits and the first and second rails, that is controllable to achieve alternative first and second states in which: (3a) in the first state, the first and second switching circuits are coupled in series across the source of AC power and (3b) in the second state, the first and second switching circuits are coupled in parallel across the source of AC power to reduce an overall loss associated with the first and second switches and (4) a boost inductor, coupled in series with first and second switching circuits, that provides a conductive path for the input DC voltage to flow through the first and second switching circuits to charge the first and second capacitors, respectively.
Abstract:
A three-phase boost converter having wye-connected input capacitors and a method of operating the same. The boost converter includes first, second and third phase inputs and an output. In one embodiment, the boost converter includes first, second and third inductors coupled to the first, second and third phase inputs, respectively, and operable in a discontinuous conduction mode (DCM). The boost converter further includes first and second switches coupled between corresponding rails of the output. The boost converter still further includes first, second and third capacitors coupled between the first, second and third phase inputs, respectively, and a node between the first and second switches. The first and second switches cooperate progressively to employ a voltage across the rails less a voltage across the first, second and third capacitors to discharge currents through the first, second and third inductors, respectively, and thereby reduce input current THD on all three of the phase inputs.
Abstract:
A multiple output dc to dc converter is described that has multiple regulated output voltages. This is achieved by using a common subcircuit in conjunction with multiple input subcircuits to power multiple output circuits. The common subcircuit is used with an input subcircuit to form a converter input circuit which with a corresponding output circuit produces an output voltage. Any number of input subcircuits can be used with the common subcircuit to produce a corresponding amount of output voltages. The multiple output dc to dc converter described produces output voltage of the same quality as using parallel converters but with a cost and complexity similar to that of using inferior secondary side switches for auxiliary outputs.
Abstract:
A power factor correction system with an EMI line filter at the input includes circuitry to sense the capacitor current of the EMI filter to improve the accuracy of the power factor enhancement. The circuitry consists of a current sensing means connected after the EMI filter, and a voltage sensing capacitor which derives its input signal from a pair of diodes separate from the conventional 4-diode rectifier bridge, which are connected either before or after the EMI filter. The current-sensing means, which may be a resistor, and the voltage-sensing capacitor are tightly coupled to the current control loop of the power factor correction system to compensate for the current in the EMI filter capacitors.
Abstract:
The present invention provides compounds having formula (I): wherein R1, R2, R3 and n are as described generally and in classes and subclasses herein, and additionally provides pharmaceutical compositions thereof, and methods for the use thereof in the treatment of inflammatory or autoimmune and proliferative disorders and as inhibitors of cell adhesion molecule expression and inflammatory cytokine signal transduction generally.
Abstract:
As discussed above, there remains a need for the development of novel therapeutic agents useful for treating inflammatory or autoimmune and proliferative diseases. The present invention provides novel compounds of general formula (I), and pharmaceutical compositions thereof, as described generally and in classes and subclasses herein, as well as methods of making and using such compounds.
Abstract:
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.
Abstract:
For use with a boost converter having a boost inductor couplable to a source of electrical power, a rectifier coupled to the boost inductor and a boost switch coupled across the rectifier, the boost converter operable in discontinuous mode, a circuit for, and method of, providing a reduced output voltage from the boost converter. In one embodiment, the circuit includes an autotransformer, coupled across an output of the boost converter, having an intermediate tap that provides a reduced output voltage at the output.