A power converter delivers electrical power from an electrical power source to a load according to a plurality of operation modes corresponding to different levels of input voltage or output current. The power converter comprises a power stage for delivering the electrical power from the power source to the load, a switch in the power stage that electrically couples or decouples the load to the power source, and a switch controller coupled to the switch for controlling the on-times and off-times of the switch according to the plurality of operation modes. Each of the operation modes correspond to associated ranges of at least one of an input voltage to the power converter and an output current from the power converter, where the associated ranges are different for each of the operation modes.

System and method for input current shaping in a power converter

A power converter comprises a primary switch network coupled to a power source, wherein the primary switch network comprises a plurality of power switches, a controller configured to generate gate drive signals for the plurality of power switches, a secondary rectifier coupled to an output, a first transformer having a first winding coupled to the primary switch network, a second winding coupled to the secondary rectifier and a third winding coupled to the controller and a second transformer having a fourth winding coupled to the primary switch network, a fifth winding coupled to the secondary rectifier and a sixth winding coupled to the controller, wherein a voltage signal from the third winding and/or the sixth winding is processed to provide a feedback of a voltage at the output.

Zero Voltage Switching Half-Bridge Converters

A first AC power source comprising a fuel cell power plant (18), and a second power source, typically grid (10), are normally connected via a high speed isolation switching means (19) to provide sufficient AC power to a critical load (14).

System for providing assured power to a critical load

A power conditioner interfaces a load to a fuel cell 10 that produces a low voltage that varies with the load. A dc-to-ac inverter 16 operates with a low voltage input provided by a dc bus 14 . When a positive step load change occurs, a low voltage battery 22 provides power equal to the step change until the fuel cell 10 is able to provide enough power to support the entire load. The power from the battery 22 is supplied to the varying dc bus 14 through a boost converter 12 . When very large positive load step changes occur, the battery can feed power to the dc bus through diode D 1 , rather than through the boost converter. Diode D 1 does not need to be used, but its use allows the boost converter to be sized for common load changes rather than for the maximum possible load change (such as might be seen during a faulted output). A buck converter converts the variable voltage on the dc bus 14 to the appropriate float charging voltage of the battery. The buck converter also supplies power for auxiliary equipment when available from the fuel cell. If the fuel cell is unable to provide the auxiliary power (such as during startup or load transients), then the auxiliary power can come directly from the battery.

High efficiency power conditioner employing low voltage DC bus and buck and boost converters

A selector circuit configured to select among a DC power source and a plurality of batteries for an electronic device. The selector circuit is responsive to an output signal from an associated power management unit. The selector circuit is further configured to permit parallel operation of two or more of the batteries. The selector circuit may further act to independently verify power conditions and override instructions from the PMU in certain instances to enhance power supply safety and battery life such as by preventing inter battery current flow from a higher potential battery to a lower potential battery coupled in parallel. A power supply block including the selector circuit and an electronic device including the power supply block is also provided. The selector circuit may be integrated with a charging circuit on one integrated circuit.

Selector circuit for power management in multiple battery systems

For use with a power factor correction circuit, a current mode controller, a method of operating current mode control to achieve power factor correction thereof and a power supply incorporating the controller or the method. In one embodiment, the controller includes: (1) a modulator, coupled to a switch in the power factor correction circuit, that senses an electrical characteristic and a current passing through the power factor correction circuit and provides, in response thereto, a control signal to the switch and (2) a compensation circuit, coupled to an input of the power factor correction circuit, that provides a compensation signal to the modulator that is a function of a rectified line voltage provided to the input of the power factor correction circuit. The compensation signal causes the modulator to modify the control signal to reduce a total harmonic distortion (THD) of the power factor correction circuit.

Current mode controller for continuous conduction mode power factor correction circuit and method of operation thereof

A power factor controller, a method of controlling power factor and a power converter employing either the controller or the method. The controller includes: (1) a ramp circuit that senses an output voltage of a converter being controlled and generates an intermediate waveform that rises as a function of a magnitude of the output voltage and (2) a drive circuit, coupled to the ramp circuit, that senses a current in the converter and causes the intermediate waveform to fall at a time that is a function of a magnitude of the current, the drive circuit generating a drive signal for the converter from the intermediate waveform.

System and method for controlling power factor and power converter employing the same

A split-boost converter having a main inductor, first and second main switches and floating and fixed outputs and a method of operating the same. In one embodiment, the converter includes an auxiliary diode coupled between the main inductor and a first rail of the floating output, and an auxiliary switch coupled to a node between the main inductor and the auxiliary diode and a second rail of the floating output. The converter is operable in a first mode, when an input voltage of the converter at least equals an output voltage of the converter, in which the auxiliary switch remains open and the first and second main switches are modulated to operate the converter. The converter is further operable in a second mode, when an input voltage of the converter is less than an output voltage of the converter, in which the first and second main switches remain closed and the auxiliary switch is modulated to operate the converter.

Dual mode split-boost converter and method of operation thereof

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.

Phase selection circuit for three phase power converter and method of operation thereof

For use in a power supply having a rectifying diode and a snubber circuit that includes a snubber inductor for absorbing a portion of a reverse recovery current associated with the rectifying diode, a circuit and method for resetting the snubber inductor and a power supply employing the circuit and method. In one embodiment, the circuit includes a reset capacitor, coupled to the snubber inductor, that has sufficient capacity to impress a resetting voltage across the snubber inductor. The circuit also includes an activation circuit, coupled between the reset capacitor and an output of the power supply, that creates a voltage differential between the reset capacitor and the output to allow the reset capacitor to attain the resetting voltage.

Hengchun Mao

Papers

Current mode controller for continuous conduction mode power factor correction circuit and method of operation thereof

System and method for controlling power factor and power converter employing the same

Dual mode split-boost converter and method of operation thereof

Phase selection circuit for three phase power converter and method of operation thereof

Power supply snubber reset circuit