A crystal that is useful for semiconductor element and a semiconductor element that has enhanced electrical properties are provided. A crystal, including: a corundum structured crystalline oxide, the crystalline oxide including gallium and/or indium, and the crystalline oxide further including a metal of Group 4 of the periodic table. The crystal is used to make a semiconductor element, and the obtained semiconductor element is used to make a semiconductor device such as a power card. Also, the semiconductor element and the semiconductor device are used to make a semiconductor system.

A three-phase AC to DC converter includes a first converter stage for converting between three phase voltages at three phase terminals and a first signal at a first intermediate node and a second intermediate node. A phase selector is configured to selectively connect the three phase terminals to a third intermediate node. The converter includes a second converter stage, a DC link connecting the first and second converter stages, and a galvanically isolated DC/DC converter stage having a first side connected to output nodes of the second converter stage and a first common node. A second side of the DC/DC converter stage is galvanically isolated from the first side. The first common node is connected to the third intermediate node. The difference of a first current applied to the DC/DC converter at output nodes of the second converter stage is provided at the third intermediate node.

A flyback converter and forward converter is described that include an input coil, a primary switch connected in series with the input coil, and an output coil magnetically coupled to the input coil. The input coil has an input side connected to an input of the circuit and a switch side connected to the primary switch. The converter further includes an input side clamp circuit, the input side clamp circuit including an energy store and a switch arrangement controlled such that the leakage inductance energy stored, in use, in the energy store, can be discharged to the input side of the input coil.

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 conversion circuit includes an input positive terminal, an input negative terminal, an output positive terminal, an output negative terminal, a first switch bridge arm, a first resonant branch, a capacitor branch, an output inductor unit and an output capacitor. The input negative terminal is electrically connected with the output negative terminal. The first switch bridge arm is electrically connected between the input positive terminal and the input negative terminal. The first switch bridge arm includes a first switch, a second switch, a third switch and a fourth switch. The first switch and the second switch are electrically connected with a first node. The second switch and the third switch are electrically connected with a second node. The third switch and the fourth switch are electrically connected with a third node. The first resonant branch is electrically connected between the first node and the third node.

A power conversion circuit includes a first terminal, a second terminal, a first switching conversion unit, a second switching conversion unit, a flying capacitor and a magnetic element. The first switching conversion unit includes a first switch and a third switch. The second switching conversion unit includes a second switch and a fourth switch. The magnetic element includes two first windings and a second winding. A first one of the two first windings is serially connected between the flying capacitor and the second terminal. A second one of the two first windings is serially connected between the second switch and the second terminal. The second winding is serially connected with the flying capacitor and the first one of the two first windings. A turn ratio between the second winding, the first one of the two first windings and the second one of the two first windings is N:1:1.

An electrical power converter (1, 1′, 1″) includes a DC link capacitor (3, 3′, 3″) configured for connection to a DC power source to provide an input load, at least one pair of semiconductor switches (2a, 2b, 2c, 2a′, 2b′, 2a″, 2b″) connected in parallel with the DC link capacitor (3, 3′, 3″) and positioned on either side of an output load terminal (10a, 10b, 10c, 10a′, 10b′, 10a″, 10b″). The electrical power converter (1, 1′, 1″) further includes an inductive current sensor (12, 12′, 12″), arranged to sense a primary current from a terminal of the DC link capacitor (3, 3′, 3″), and a detection circuit (14), connected to the inductive current sensor (12, 12′, 12″) and arranged to monitor for an over-current condition, and to produce an output which causes at least one of the pair of semiconductor switches (2a, 2b, 2c, 2a′, 2b′, 2a″, 2b″) to be switched to a non-conducting state when an over-current condition is detected.

A control circuit for a resonant circuit includes a resonant current detecting circuit, a current adjustment circuit and an on-time control circuit. The resonant current detecting circuit is configured to receive a resonant current, a first reference and a second reference, and to provide a detected current signal based on the resonant current, the first reference and the second reference. The current adjustment circuit is configured to receive the detected current signal and a charging reference, and to provide an on-time control signal based on the detected current signal and the charging reference. The on-time control circuit is configured to receive the on-time control signal and an on-time initial value, and to provide an on-time signal to control a switch of the resonant circuit based on the on-time control signal and the on-time initial value.

A power system may comprise a plurality of power sources, each connected to a corresponding power regulator. The power regulators may be connected in series or in parallel, and may form a string. Each power regulator may comprise input terminals connected to the corresponding power source, output terminals, and a power converter that may be configured to convert input power from the corresponding power source to output power. The power regulator may further comprise a regulator communications module that may be configured to receive a power regulation indication relating to regulating an operational characteristic of the power regulator. The regulator controller may be configured to instruct the power converter to increase or decrease the regulator operational characteristic based on the power regulation indication, and based on power production characteristics of the power regulator.

Adaptive enabling and disabling is described for valley switching in a power factor correction boost converter. In one example, a boost converter control system includes an amplitude detector to receive an amplitude signal from a boost converter that is related to ringing of the boost converter output. The amplitude detector determines the ringing amplitude. A valley switching controller compares the ringing amplitude to a first high amplitude threshold when valley switching is enabled and generates a valley switching disable signal if the ringing amplitude is below the first high amplitude threshold. A cycle controller coupled to the boost converter generates a drive signal to control switching of the boost converter and coupled to the valley switching controller receives the valley switching disable signal to generate the drive signal without valley switching in response to the valley switching disable signal.