A primary side regulated isolation voltage converter. The primary side regulated isolation voltage converter comprises a control module and a ripple control circuit. The control module receives the voltage feedback signal and determines whether the isolation voltage converter operates in a light load state. When the isolation voltage converter operates in a light load state, the ripple control circuit senses the ripple of an output voltage signal to generate a ripple signal, and compare the ripple signal with a ripple threshold. When the ripple signal is larger than the ripple threshold, the isolation voltage converter jumps out the light load state.

Apparatus for power conversion are provided. One apparatus includes a power converter including an input circuit and an output circuit. The power converter is configured to receive power from a source for providing power at a DC source voltage V.sub.S. The power converter is adapted to convert power from the input circuit to the output circuit at a substantially fixed voltage transformation ratio K.sub.DC=V.sub.OUT/V.sub.IN at an output current, wherein V.sub.IN is an input voltage and V.sub.OUT is an output voltage. The input circuit and at least a portion of the output circuit are connected in series across the source, such that an absolute value of the input voltage V.sub.IN applied to the input circuit is approximately equal to the absolute value of the DC source voltage V.sub.S minus a number N times the absolute value of the output voltage V.sub.OUT, where N is at least 1.

A circuit assembly is provided for producing a test voltage for testing a test object, comprising two high voltage sources for producing a positive and negative high voltage of variable amplitude at respective outputs thereof and a high voltage switch assembly, which is arranged between the outputs of the two high voltage sources and the test object and which can be switched suitably in order to successively charge and discharge the test object, wherein furthermore a closed-loop controller is provided, which measures the present test voltage on the test object and acts on the high-voltage switch assembly in order to charge and discharge the test object in a defined manner in dependence on the measured test voltage.

There is provided a power conversion method of a power conversion device including a plurality of primary side ports disposed in a primary side circuit and a secondary side port disposed in a secondary side circuit magnetically coupled to the primary side circuit using a transformer, the power conversion device adjusting transmitted power transmitted between the primary side circuit and the secondary side circuit, and a duty ratio of the switching of the primary side circuit or a duty ratio of the switching of the secondary side circuit being changed, including fixing the first duty ratio or the second duty ratio to the third duty ratio when the phase difference is the upper limit value and the detected voltage of the first primary side port is less than the product of the target voltage of the second primary side port and 100/the third duty ratio.

According to at least one aspect, embodiments herein provide an adaptive battery pack module comprising a Li-ion battery, a low-voltage bus coupled to the Li-ion battery, a bi-directional DC-DC converter coupled to the low-voltage bus, a low-voltage output coupled to the low-voltage bus, a high-voltage output, and a high-voltage bus coupled between the bi-directional DC-DC converter and the high-voltage output, wherein the low-voltage output is configured to be coupled to at least one Li-ion battery of at least one external battery pack module, and wherein the bi-directional DC-DC converter is configured to receive DC power from the Li-ion battery and the at least one Li-ion battery of the at least one external battery pack module via the low-voltage bus, convert the received DC power into output DC power, and provide the output DC power to the high-voltage bus.

A driver circuit for light emitting diodes (LEDs) and a driving method for LEDs. The driver circuit comprises a single stage DC-DC converter with multiple output channels, the converter comprising one set of switches on a primary side of the converter, a rectifier and voltage multiplier component at the secondary side; and a dimming control component configured to control the respective switches on the primary side of the converter for controlling an output current in the multiple output channels.

A power delivery (PD) device includes: an AC/DC converter connected to an AC input, the AC/DC converter configured to change the AC input to a desired voltage value to be output in accordance with a first voltage changing control signal supplied from outside; and a DC/DC converter connected between an output of the AC/DC converter and a DC output, the DC/DC converter configured to change the output from the AC/DC converter to a desired voltage value to be output as a DC output in accordance with a second voltage changing control signal supplied from outside, wherein the AC/DC converter at a previous stage and the DC/DC converter at a subsequent stage are interlocked to change the output voltage to desired target voltage. There can be provided the PD device capable of delivering power with high power efficiency over the wide voltage ranges.

A method of controlling a multilevel converter, a computer program and a controller for a converter is provided. The method includes determining a transition voltage from a control period to a following control period, analyzing the switching cells of each phase leg, selecting capacitors to provide the transition voltage and synthesize the output voltage for the following control period, and connecting the selected capacitors during the following control period. The analyzing of each switching cell includes analyzing a first switching leg and a second switching leg of the switching cell. The method includes determining whether a change of state of the first switching leg would contribute to the direction of the transition voltage, and determining whether a change of state of the second switching leg would contribute to the direction of the transition voltage, and determining the internal conditions of each of the first and the second switching leg that are determined as contributing to the transition. Thus, the two legs of the H-bridge are analyzed separately. The selecting of capacitors is performed by selecting the capacitors of the switching legs of the phase leg for the transition voltage on the basis of the determined internal conditions of the switching legs, including comparing the internal conditions of all the switching legs of the phase leg. A controller is configured to control the multilevel converter by performing the method.

An electric power conversion device includes a transformer composed of three or more windings magnetically coupled with each other, wherein power supply sources, are connected to at least two windings, via switching circuits, a load is connected to at least one winding, and a control circuit temporally divides, within one switching period, a total ON time during which power is supplied, in accordance with the number of the power supply sources, to supply power, the one switching period being the minimum repetitive unit during which power is supplied alternately. The control circuit allocates the divided ON times to the respective switching circuits, and the switching circuits, supply power from the power supply sources, to the load side during the allocated ON times, respectively.

A switch-mode power supply device (1) is disclosed. The switch-mode power supply device (1) has a main circuit (6) configured to receive a DC input voltage and to provide a DC output voltage. The main circuit (6) comprises: an inductor element (12) generating the DC output voltage, a switching element (9) connected to the inductor element (12), and a controller (7) configured to switch the switching element (9) between a conducting state and a non-conducting state, wherein the switching element (9) is configured to feed a pulsed direct current to a ground potential (10). The switch-mode power supply (1) also has an auxiliary circuit (16) configured to provide an auxiliary voltage. The auxiliary circuit (16) comprises an auxiliary inductor (18) connected to receive the pulsed direct current and magnetically isolated from the inductor element (12).