We disclose a III-nitride semiconductor based heterojunction power device comprising: a first heterojunction transistor formed on a substrate, the first heterojunction transistor comprising: a first III-nitride semiconductor region formed over the substrate, wherein the first III-nitride semiconductor region comprises a first heterojunction comprising at least one two dimensional carrier gas; a first terminal operatively connected to the first III-nitride semiconductor region; a second terminal laterally spaced from the first terminal and operatively connected to the first III-nitride semiconductor region; a first plurality of highly doped semiconductor regions of a first polarity formed over the first III-nitride semiconductor region, the first plurality of highly doped semiconductor regions being formed between the first terminal and the second terminal; a first gate region operatively connected to the first plurality of highly doped semiconductor regions; and a second heterojunction transistor formed on the substrate. The second heterojunction transistor comprises: a second III-nitride semiconductor region formed over the substrate, wherein the second III-nitride semiconductor region comprises a second heterojunction comprising at least one two dimensional carrier gas; a third terminal operatively connected to the second III-nitride semiconductor region; a fourth terminal laterally spaced from the third terminal in the first dimension and operatively connected to the second III-nitride semiconductor region; a second gate region being formed over the second III-nitride semiconductor region, and between the third terminal and the fourth terminal. One of the first and second heterojunction transistors is an enhancement mode field effect transistor and the other of the first and second heterojunction transistors is a depletion mode field effect transistor.

An integrated circuit for a power supply including a power transistor, the integrated circuit being configured to switch and drive the power transistor. The integrated circuit includes: a first terminal to which a first switch is coupled; a first determination circuit configured to determine, based on a voltage level at the first terminal, whether to operate the integrated circuit in a first mode or a second mode, a power consumption in the second mode being greater than a power consumption in the first mode; a first power supply voltage generation circuit configured to stop generating a first power supply voltage when the integrated circuit operates in the first mode, and generate the first power supply voltage when the integrated circuit operates in the second mode; and a driver circuit configured to receive the first power supply voltage, to switch and drive the power transistor.

Various embodiments relate to a converter controller configured to control a resonant converter, including: an integrator configured to receive a current measurement signal from a current measurement circuit in the resonant converter and to produce a capacitor voltage signal indicative of the voltage at the resonant capacitor; a control logic configured to produce a high side driver signal, a low side driver signal, a symmetry error signal based upon the capacitor voltage signal and the current measurement signal; and a symmetry controller configured to produce a symmetry correction signal based upon the symmetry error signal, wherein the symmetry error signal is input into the integrator to control the duty cycle of the high side driver signal and the low side driver signal, wherein the high side driver signal and the low side driver signal control the operation of the resonant converter.

A circuit for use in an LLC converter comprises a first primary side switch, a first secondary side switch assembly, a controller, and a resonant network. The controller is configured to measure, on the LLC primary side, a first voltage and determine a delay due to the first voltage. The controller is also configured to apply a first gate voltage to the first primary side switch to transition the first primary side switch from an off state to an on state and apply a second gate voltage to the first secondary side switch assembly to transition the first secondary side switch assembly from an off state to an on state. The application of the first and second gate voltages are separated by a synchronous rectifier delay based on the delay due to the first voltage, the first voltage comprising a voltage across the resonant capacitor.

A direct-current voltage conversion circuit having on/off control with a dead-time period performed alternately on a first switch and a second switch included in a direct-current voltage conversion circuit. When alternating current flows in a series circuit part including two transformers magnetically independent, current flows in an output circuit including a secondary side of one transformer, and energy is accumulated in the other transformer. The permeabilities of the magnetic cores in the first and second transformers is between 15 and 120.

A reactor includes a plurality of windings, a coupling core, and an inductor core. A coupling core configured to form a coupling closed magnetic circuit that magnetically couples the plurality of windings, the plurality of windings being wound around the coupling core; and. An inductor core, which includes a main part, a first projection part projecting from one end of the main part, and a second projection part projecting from another end of the main part, and each of the first projection part and the second projection part is magnetically connected to the coupling core. The inductor core forms an inductor closed magnetic circuit together with a part of the coupling core around which one winding of the plurality of windings is wound.

A reactor includes a plurality of windings, a coupling core, and an inductor core. A coupling core configured to form a coupling closed magnetic circuit that magnetically couples the plurality of windings, the plurality of windings being wound around the coupling core; and. An inductor core, which includes a main part, a first projection part projecting from one end of the main part, and a second projection part projecting from another end of the main part, and each of the first projection part and the second projection part is magnetically connected to the coupling core. The inductor core forms an inductor closed magnetic circuit together with a part of the coupling core around which one winding of the plurality of windings is wound.

A driver circuit is configured to control a power transistor. The driver circuit comprises a signal generator configured to generate a control signal for the power transistor based on a supply signal and an input signal from a control unit. In addition, the driver circuit includes a ripple detector configured to receive the supply signal and determine whether the supply signal includes a ripple error. In some examples, the ripple detector may be configured to send a warning signal to the control unit in response to detecting the ripple error.

A multiple output universal serial bus travel adaptor includes: at least one AC-DC converter for converting an AC power to a first DC power; at least one DC-DC converter for providing a second DC power according to the first DC power; plural switches which are coupled to the AC-DC converter and/or the DC-DC converter to provide the first DC power or the second DC power to corresponding connectors according to operation signals; and a protocol controller configured to generate the operation signals according to at least one of the following parameters: a) the types of the connectors; b) whether there is a mobile device connected with the connectors; c) a first command from the mobile device; d) the power consumed by the mobile devices; e) the currents flowing through the connectors; and f) the voltages at the connectors.

A multiple output universal serial bus travel adaptor includes: at least one AC-DC converter for converting an AC power to a first DC power; at least one DC-DC converter for providing a second DC power according to the first DC power; plural switches which are coupled to the AC-DC converter and/or the DC-DC converter to provide the first DC power or the second DC power to corresponding connectors according to operation signals; and a protocol controller configured to generate the operation signals according to at least one of the following parameters: a) the types of the connectors; b) whether there is a mobile device connected with the connectors; c) a first command from the mobile device; d) the power consumed by the mobile devices; e) the currents flowing through the connectors; and f) the voltages at the connectors.