A half bridge DC-DC converter device includes a primary circuit and a secondary circuit, which include separate windings that are disposed around a magnetic core. The first circuit includes two switches and a drive circuit to turn the two switches on and off in an alternating fashion. The primary circuit further includes two thermal regulating components to regulate the current at the base of the two switches over a range of operating temperatures. The regulation of base current over a range of different operating temperatures results in the half bridge converter device being efficient and maintaining a stable switching frequency over the operational temperature range.

A controller of a power converter is coupled to a switch assembly and configured to perform a hold-up time procedure that causes the controller to control first and second switching elements into opposite conducting states during a first period of time of a pulse cycle and into alternate opposite conducting states during a second period of time of the pulse cycle. The hold-up time procedure also causes the controller to control a first pair of synchronous rectifier switching devices into a conducting state during a third period of time overlapping less than all of the first period of time and into the conducting state during a fourth period of time overlapping less than all of the second period of time. A second pair of synchronous rectifier switching devices is controlled into a non-conducting state during the first and second periods of time.

This application provides a switching conversion circuit, including: a power module, supplying power to a switching conversion module and an IC controller; and the switching conversion module is an asymmetrical half-bridge flyback structure and includes at least a first switching transistor, a second switching transistor, a first capacitor, and a transformer. The transformer includes a first secondary-side winding and a second secondary-side winding, and the first secondary-side winding of the transformer is coupled to a load. The IC controller turns on the first switching transistor or the second switching transistor based on a value of a first voltage, so that the switching conversion module enters an operating state to supply power to the load; and turns off the first switching transistor and the second switching transistor based on a value of a second voltage, so that the switching conversion module stops supplying power to the load.

A power supply may include a power converter circuit may be configured to control a magnitude of an output voltage, and generate a signal indicative of the magnitude of the output voltage. The power supply may include an over-power protection circuit that is configured to receive a feedback signal indicative of a magnitude of an input current of the power converter circuit. The power supply may include a control circuit that is configured to determine a magnitude of a requested power based on the signal indicative of the magnitude of the output voltage, and disable the power supply (e.g., control the magnitude of the output voltage to be zero volts) when the magnitude of the requested power is greater than a second threshold and the magnitude of input power indicated by the first feedback signal is less than a third threshold.

The power supply apparatus alternately repeats a control between a first control of varying a frequency of switching operation within a predetermined range and for a predetermined cycle according to a frequency determined based on a feedback voltage, and a second control of varying the frequency within a range narrower than the predetermined range or a third control of controlling the frequency to be a constant frequency.

At a first node (N1), an intermediate voltage potential occurs between a voltage potential of the first input terminal (P1) and a voltage potential of the second input terminal (P2). A second node (N2) is connected to ends (b1 to b3) of primary windings (w1, w4, w7) of transformers (T1 to T3) of LLC resonant converters (11 to 13). A switch circuit is connected between the first node (N1) and the second node (N2). A control circuit (15) is configured to turn on a switch circuit (SW) when a load current of a load apparatus (6) connected to a first output terminal (P3) and a second output terminal (P4) is equal to or smaller than a predetermined criterion and turn off the switch circuit (SW) when the load current of the load apparatus (6) is larger than the predetermined criterion.

A two-stage power converter can incorporate a buck pre-regulator and a resonant bus converter. Such a converter may be operated to achieve unconditional soft switching operation (zero voltage switching a/k/a ZVS) over a wide input and output range, while delivering excellent power conversion efficiency at lower power levels and in a no load condition.

This application discloses a converter and a power adapter, to reduce an energy loss of the power adapter. The converter includes a direct current power supply, a main power transistor, an auxiliary power transistor, a first capacitor, a transformer, and a control circuit. The first capacitor and the transformer are connected in series to form a series circuit. The series circuit is connected to a first terminal and a second terminal of the auxiliary power transistor in parallel. The control circuit is configured to: when the main power transistor is in a cutoff state and a target voltage reaches a target valley voltage, control the main power transistor to be conducted. The target voltage is a voltage between the first terminal of the main power transistor and the ground.

The present disclosure provides a power conversion device. The power conversion device includes the multi-level power factor correction circuit, the at least one output capacitor, the at least one input capacitor group, the first resonant conversion circuit and the second resonant conversion circuit. The at least one input capacitor group includes the first input capacitor and the second input capacitor. The at least one output capacitor is connected to an output part of the multi-level power factor correction circuit. The at least one input capacitor group is connected to the at least one output capacitor in parallel. The second input capacitor is connected to the first input capacitor in series. The input part of the first resonant conversion circuit is connected to first input capacitor in parallel. The input part of the second resonant conversion circuit is connected to the second input capacitor in parallel.

A method for controlling switching of an electrical system comprising having at least one frequency-controlled switch arm, includes the following steps: closing a first top or bottom switch, implementing a predetermined downtime and opening a second switch, for a period corresponding to the control frequency, and then: opening the first switch, comparing the voltage measured at the midpoint with a voltage threshold, determining a second instant t2 at which the voltage measured at the midpoint crosses the voltage threshold, closing the second switch at the second instant t2, calculating a downtime DT adjusted according to a formula which is a function of the control frequency Fsw, a first instant t1 and a second instant t2, the adjusted downtime being implemented as of the subsequent switching.