A low voltage converter includes a transformer controller configured to control at least one switch to supply a high voltage of a main battery to a transformer. The transformer is configured to convert the high voltage of the main battery to a low voltage. An output circuit is configured to output the low voltage to a load or a battery through a capacitor coupled in series with an inductor is provided.

In an embodiment, a method for operating an ACF converter includes: turning on a low-side transistor that is coupled between a primary winding of a transformer and a reference terminal to cause a forward current to enter the primary winding, turning off the low-side transistor; after turning off the low-side transistor, turning on a high-side transistor that is coupled between the primary winding and a clamp capacitor to cause a reverse current to flow through the primary winding; and after turning on the high-side transistor, when an overcurrent of the reverse current is not detected, keeping the high-side transistor on for a first period of time, and turning off the high-side transistor after the first period of time, and when the overcurrent of the reverse current is detected, turning off the high-side transistor without keeping the high-side transistor on for the first period of time.

Disclosed herein is an improved flyback converter that separates the magnetic components of the converter into a transformer and a separate, discrete energy storage inductor. This arrangement can improve the operating efficiency of the converter by reducing the commutation losses as compared to a conventional flyback converter. The magnetic components may be constructed on separate magnetic cores or may be constructed on magnetic cores having at least one common element, thereby allowing for at least partial magnetic flux cancellation in a portion of the core, reducing core losses.

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 circuit including positive and negative input terminals, a clamping branch circuit, a first primary switch, a transformer, a rectifier circuit, a resonant inductor, a resonant capacitor, and positive and negative output terminals. The clamping branch circuit includes a clamping capacitor and a second primary switch serially connected between the first and second terminals thereof. The first terminal is coupled to the positive input terminal. The first primary switch is connected between the second terminal and the negative input terminal. The primary winding of the transformer is connected to the clamping branch circuit in parallel. The rectifier circuit includes first and second bridge arms connected in parallel. Connection terminals in the first and second bridge arms are coupled to two terminals of the secondary winding of the transformer correspondingly. The first and second bridge arms are coupled between the positive and negative output terminals.

A system and method for snubbing transformer leakage energy in a power supply having a transformer and a main switch, in which leakage energy is stored in a capacitor as stored leakage energy when the main switch is turned off, and the stored leakage energy is transferred to the transformer through an inductor when the main switch is turned on.

A power converter-circuit (100) having a transformer (T), comprising a snubber-circuit (C.sub.sn, D.sub.Sn,S3, S.sub.3, D.sub.Sn,S4) for suppressing voltage peaks on a secondary side of the transformer (T) that comprises a snubber capacitor (C.sub.sn); and an auxiliary DC-DC converter (101) having a first input connected with the snubber capacitor (C.sub.sn) and a first output connected with a first output (V.sub.Out) of the power converter-circuit (100). This circuit increases efficiency of electrical conversion and reduces thermal losses.

Disclosed herein is an improved flyback converter that separates the magnetic components of the converter into a transformer and a separate, discrete energy storage inductor. This arrangement can improve the operating efficiency of the converter by reducing the commutation losses as compared to a conventional flyback converter. The magnetic components may be constructed on separate magnetic cores or may be constructed on magnetic cores having at least one common element, thereby allowing for at least partial magnetic flux cancellation in a portion of the core, reducing core losses.

Disclosed herein is an improved flyback converter that separates the magnetic components of the converter into a transformer and a separate, discrete energy storage inductor. This arrangement can improve the operating efficiency of the converter by reducing the commutation losses as compared to a conventional flyback converter. The magnetic components may be constructed on separate magnetic cores or may be constructed on magnetic cores having at least one common element, thereby allowing for at least partial magnetic flux cancellation in a portion of the core, reducing core losses.

An active clamp flyback (ACF) converter can be used to convert AC voltages to DC voltages and offers the ability to reuse leakage energy and a negative magnetizing current to achieve zero-volt-switching. The leakage energy can vary with system design and therefore may be difficult to control, but the negative magnetizing current can be controlled by adjusting a switching frequency of the ACF converter. The adjustment can be determined by comparing the negative magnetizing current to a threshold. Using a fixed threshold may not be optimal because variations in system operating conditions, such as load current, line voltage, and output voltage, can affect the amount of negative magnetizing current required for zero-volt-switching (i.e., can affect the threshold). Additionally, a range of possible switch technologies can affect the threshold. The present disclosure describes an adaptable threshold for a variable frequency ACF converter that allows for efficient switching.