Abstract:
For use in a boost converter having a boost inductor coupled between an input and an output of the boost converter and an output capacitor coupled between rails of the output, an energy storage circuit for, and method of, extending a holdup time of the boost converter. In one embodiment, the energy storage circuit includes: (1) a holdup capacitor coupled to a first rail of the input, (2) a holdup switch, coupled to a second rail of the input and the holdup capacitor, capable of closing during a holdup mode to allow the holdup capacitor to discharge current into the input and (3) a voltage stabilizing circuit, coupled between the holdup capacitor and the output capacitor, that: (3a) when the boost converter is in a normal mode, provides a substantially impeded path for charge current to flow from the output capacitor to charge the holdup capacitor, and (3b) when the boost converter is in an initial phase of the holdup mode, provides a substantially unimpeded path for holdup current to flow from the holdup capacitor to the output capacitor prior to the closing of the holdup switch.
Abstract:
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.
Abstract:
Various DC/DC converter topologies having improved electromagnetic interference (EMI) characteristics and methods of providing dual DC outputs with such converters. One embodiment of one DC/DC converter having dual, EMI-quiet outputs includes: (1) a first subcircuit, having a series-coupled first switch, first inductor and first capacitor and an output across the first capacitor, coupled between first and second DC input rails, (2) a second subcircuit, having a second switch, second inductor and second capacitor and an output across the second capacitor, coupled between the first and second DC input rails in anti-parallel with the first subcircuit, (3) a first diode coupling a node between the first switch and the first inductor and a node between the second inductor and the second capacitor and (4) a second diode coupling a node between the first inductor and the first capacitor and a second node between the second switch and the second inductor. A further embodiment adds third and fourth series-coupled capacitors coupling the first and second DC input rails and replaces the first and second diodes with: (1) a first converter diode coupling a node between the first switch and the first inductor and a node between the second switch and the second inductor, (2) a first snubber diode coupling a node between the third and fourth capacitors and the node between the first switch and the first inductor and (3) a second snubber diode coupling the node between the third and fourth capacitors and the node between the second switch and the second inductor.
Abstract:
A power converter for converting three phase input power to DC output power and a method of effecting such conversion. The power converter includes: (1) three single phase DC converters, each having outputs, that receive the three phase input power, (2) a DC/DC converter coupled to the outputs of the three single phase DC converters and (3) a converter selection circuit, associated with the three single phase DC converters, that selects a selected subset of the three single phase DC converters as a function of an electrical characteristic of each phase of the three phase input power to conduct a portion of the three phase input power to the DC/DC converter, the converter selection circuit permitting the power converter to operate on the three phase power with less than three DC/DC converters.
Abstract:
For use in a split-boost converter having a DC input, first and second outputs, a power train interposed between the DC input and the first and second outputs, a damped electromagnetic interference (EMI) filter circuit and method of reducing the EMI. In one embodiment, the EMI filter circuit includes (1) an EMI filter interposed between the power train and the second output, the EMI filter subject to oscillation from line disturbances arriving at the DC input and (2) a conductive path, coupling a rail of the second output to the DC input, that routes at least a portion of the line disturbances from the DC input directly to the second output to damp the oscillation of the EMI filter.
Abstract:
For use in a DC/DC converter fed by a three phase rectifier, an active circuit and method for delivering an inner phase of three phase AC input power provided to the rectifier and a power converter employing the active circuit or the method. The active circuit includes: (1) a phase selection switching circuit, coupled to the rectifier, that selects an inner phase of the three phase AC input power and (2) a switching network, coupled to the phase selection switching circuit, that controls a waveshape of at least the inner phase to the DC/DC converter thereby to reduce harmonics associated with the three phase AC input power.
Abstract:
A boost rectifier is provided with an ultra high speed diode in its direct current rail to reduce diode reverse recovery loss with or without implementing a soft switching technique. Full zero-voltage-transition (ZVT) as well as zero-current-transition (ZCT) may also be achieved by adding a simple auxiliary network across the DC rail which operates only during the short turn-on transients of the bridge switches. Similarly, a simple, inexpensive auxiliary circuit can be added to the DC rail of a conventional voltage source inverter shown to implement both ZVT and ZCT.
Abstract:
A cylinder head is prepared by integrating an upper cylinder head part and a lower cylinder head part, which are manufactured separately, into the whole, wherein the fuel injector receiving hole, the intake valve stem receiving hole and the exhaust valve stem receiving hole are respectively prepared by integrating their upper portions which are formed together with the upper cylinder head part and their lower portions which are formed together with the lower cylinder head part respectively; the intake duct and the exhaust duct are formed in the lower cylinder head part; the cylinder head water cavity is prepared by integrating an upper water cavity portion formed together with the upper cylinder head part and a lower water cavity portion formed together with the lower cylinder head part into the whole, alternatively, the cylinder head water cavity is formed, as a whole, with the lower cylinder head part.
Abstract:
A cylinder head is prepared by integrating an upper cylinder head part and a lower cylinder head part, which are manufactured separately, into the whole, wherein the fuel injector receiving hole, the intake valve stem receiving hole and the exhaust valve stem receiving hole are respectively prepared by integrating their upper portions which are formed together with the upper cylinder head part and their lower portions which are formed together with the lower cylinder head part respectively; the intake duct and the exhaust duct are formed in the lower cylinder head part; the cylinder head water cavity is prepared by integrating an upper water cavity portion formed together with the upper cylinder head part and a lower water cavity portion formed together with the lower cylinder head part into the whole, alternatively, the cylinder head water cavity is formed, as a whole, with the lower cylinder head part.
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.