Abstract: An integrated switching power supply device includes a series-connected body, a driving control element, and external terminals. In the series-connected body, a switching element, a constant current element, and a diode are connected in series. The driving control element controls to drive the constant current element. The external terminals include first to seventh external terminals. The first and second external terminals are connected to main terminals of elements of the series-connected body. The third external terminal is connected to a connection point of main terminals of the switching element or the constant current element and a main terminal of the diode. The fourth external terminal is connected to a control terminal of the switching element. The fifth external terminal supplies electric power to the driving control element. The sixth external terminal inputs reference potential. The seventh external terminal inputs a signal to the driving control element.

Abstract: A current mirror circuit converts a positive-side supply voltage of a second power supply with respect to a reference potential into an electric current so as to supply the electric current to a current/voltage converting section. The current/voltage converting section converts the electric current from the current mirror circuit into a voltage with respect to the reference potential of a first power supply so as to supply the voltage to a feedback input terminal of a switching controller. Therefore, although the reference potential of the first power supply supplied to the switching controller is different from the reference potential of the second power supply, the electric current from the current mirror circuit is not influenced by the reference potential.

Abstract: Several circuits and methods for transferring an input data signal in a digital isolator are disclosed. In an embodiment, the digital isolator includes an isolation element, input circuit, and output circuit. The isolation element includes at least one input node and at least one output node, the input circuit is electronically coupled to the input node and generates modulated differential data signals based on modulating the input data signal on a carrier signal. The input circuit operates using a first supply voltage with respect to a first ground. The output circuit is electronically coupled to the output node to receive the modulated differential data signals, operates using a second supply voltage with respect to a second ground and includes a frequency-shift keying demodulator configured to generate a demodulated data signal in response to detection of presence of the carrier signal. The output circuit further generates an output data signal.

Abstract: In a switching power supply apparatus, a first switching element is controlled by a driving voltage output from a switching control IC. A second switching control circuit controls the on-time of a second switching element so that the time ratio of the on-time of the second switching element to the on-time of the first switching element becomes almost constant with respect to a change in a load current. In a normal load state, since a square wave output from a frequency setting unit within the switching control IC is output with no change, a converter operates in a current-continuous mode. In a light load state, a driving signal generation unit within the switching control IC is subjected to blanking with the period of a signal output from a maximum frequency setting unit and an oscillation frequency is reduced. Accordingly, the converter operates in a current-discontinuous mode.

Abstract: A circuit assembly for operating a discharge lamp is disclosed having DC input terminals, a bridge circuit to implement a first bridge midpoint, an output coupling the discharge lamp thereto and a shunt resistor with a tapping point and a device for detecting overload operation. A device for ignition control of the discharge lamp, having an input for supplying a measurement signal and a switch control device is provided connected to the device for detecting overload operation and the ignition control device. The switch control device is designed to modify control signals for at least a first and second electronic switch as a function of the output signals of the device for detecting overload operation.

Abstract: A DC-DC converter includes a capacitor configured to be charged for a predetermined period by an external voltage, an inductor configured to constitute an LC resonance circuit together with the capacitor, a closed-loop current path configured to release energy accumulated in the capacitor after the predetermined period to cause a current flowing in the LC resonance circuit to oscillate, a transformer configured to receive a current flowing in the closed-loop current path, and a rectifying circuit situated on an output side of the transformer.

Abstract: A drive and control circuit for motor system and the method thereof are disclosed. The motor system could be applied in a cooling device, wherein the motor system comprises a rotor, a coil and a bridge circuit. The drive and control circuit comprises a control unit, a state detecting circuit, a load determining circuit, and a startup setting circuit. The startup setting circuit makes the motor run with the maximum torque, thus to make the motor system start up easily and quickly. The load determining circuit detects the load of the motor system, thus to generate a load determining signal to determine the speed of the motor system. The control unit could be realized with few components so as to save the costs.

Abstract: A drive transformer isolated-adaptive drive-circuit includes a power supply, a first MOSFET and a second MOSFET, the drain electrode of the first MOSFET coupled with the positive electrode of the power supply, and the source electrode of the first MOSFET coupled with the drain electrode of second MOSFET; the source of the second MOSFET coupled with the negative electrode of the power supply; a drive transformer having a first winding and a second winding; a first fast drive circuit, one end coupled with the first winding, the other end is coupled with the first MOSFET; a second fast drive circuit, one end coupled with the second winding, the other end coupled with the second MOSFET; a first adaptive-dead-time control sub-circuit; and a second adaptive-dead-time control sub-circuit.

Abstract: It is presented a high voltage DC/DC converter for converting between a first DC connection and a second DC connection. The high voltage DC/DC converter comprises: a first set of DC terminals; a second set of DC terminals); a multiphase transformer device comprising a plurality of primary windings and a corresponding plurality of secondary windings; a first converter arranged to convert DC to AC, comprising a plurality of phase legs serially connected between the first set of DC terminals, wherein each phase leg is connected to an AC connection of a respective primary winding; and a second converter arranged to convert AC from the secondary windings to DC on the second set of DC terminals.

Abstract: Implemented are a switching power supply device and a light-emitting diode lighting device in which a variation in load current can be suppressed against a wide range of variation in AC voltage. The configuration of the switching power supply device and the light-emitting diode lighting device includes: a rectifier unit which rectifies AC input voltage and outputs pulsating-current voltage; a power converting unit which receives the pulsating-current voltage and supplies a predetermined load current to a load; a current detecting unit which detects the load current; a drive control unit which controls the power converting unit to regulate the load current to a constant level; and an input voltage detecting unit which detects a variation in the AC input voltage. The drive control unit controls the power converting unit depending on the variation in the AC input voltage detected by the input voltage detecting unit.

Abstract: An integrated power quality control system includes a transformer with a primary winding, a secondary winding and a compensation winding wound on a magnetic core. A power electronic converter in the system provides a reference voltage to the compensation winding for injecting a series voltage in the secondary winding of the transformer. A controller is utilized to generate the reference voltage for the power electronic converter based on a power quality control requirement.

Abstract: A switching power source apparatus has a pulse generator of a first pulse. A first resonant series circuit receives the first pulse signal and passes a current having a 90-degree phase delay with respect to the first pulse signal. The current of the first resonant series circuit turns on/off a switching element Q21. A second resonant series circuit receives the second pulse signal and passes a current having a 90-degree phase delay with respect to the second pulse signal. The current of the second resonant series circuit turns on/off a switching element Q22. The pulse generator has a third transformer T3 that has secondary windings to output the first and second pulse signals according to a voltage that is applied to the third transformer and is synchronized with drive signals for the switching elements Q11 and Q12.

Abstract: Circuits and methods for driving electrical loads, where each is driven according to a desired current. A circuit comprising a switch mode converter comprising a transformer with primary and secondary windings, the primary connected to a voltage supply via one or more input control switches; output circuits, each comprising a switch connecting a load to an output of the secondary, each load series connected with a respective switch and in parallel with a capacitor; and a switching control circuit for control of each of the output circuit switches and for sensing a current through the loads. The switching control circuit operates the output circuit switches to maintain set current through the loads, the switching control circuit configured in successive output cycles of the switch mode converter to operate each output circuit switch in an order dependent on a forward voltage of each of the respective loads.

Abstract: A controller for use in a power converter includes a control circuit coupled to control switching of a power switch coupled between a positive input supply rail of the power converter and an energy transfer element input of the power converter. A sampling circuit is coupled to the control circuit and is coupled to receive a signal across the energy transfer element input during an off time of the power switch to provide a sampled output of the converter. The sampled output of the power converter is disabled from being resampled by the sampling circuit during an on time of the power switch. A switch conduction scheduling circuit is included in the control circuit and is coupled to the sampling circuit such that the control circuit is coupled to switch the power switch in response to the sampled output of the power converter.

Abstract: An LLC resonant power regulator system includes a transformer having a primary inductor and a secondary inductor and an input resonant tank including an input resonant capacitor, an input leakage inductor, and the primary inductor connected in series. The system also includes an input stage having a plurality of switches that are controlled in response to a respective plurality of switching signals sweeping frequency to supply an input resonant current to the input resonant tank. Each of the respective plurality of switching signals can have a fixed duty cycle and a sweeping frequency. The system further includes an output resonant tank that includes an output resonant capacitor, an output leakage inductor, and the secondary inductor connected in series. The output resonant tank can be configured to generate an oscillating output resonant current at an output.

Abstract: A method and apparatus for power conversion. In one embodiment, the apparatus comprises at least two power stages, each power stage of the at least two power stages capable of converting DC input power to DC output power; and a controller for dynamically selecting, based on a first DC power, one or more power stages of the at least two power stages for converting the first DC power to a second DC power.

Abstract: Apparatus and methods for filtering the transients of an input signal of an integrated circuit while maintaining a constant voltage at an input terminal of the integrated circuit are disclosed. In one example, the integrated circuit can be a controller of a switched-mode power supply. The controller can include a line sensing circuit coupled to receive an input signal representative of the line voltage and operable produce an output signal that can be used by other circuits within the controller. The input signal may include a current through a sense resistor coupled between the input of the power supply and the line sensing circuit. The output signal may include a scaled and filtered version of this current. The line sensing circuit can be coupled to the input terminal of the controller to receive the input signal or can directly receive the input signal.

Abstract: A power voltage conversion system for a controller integrated circuit includes a DC-to-DC converter and a controller IC. The DC-to-DC converter receivers an external DC voltage and the DC-to-DC converter at least has an inductance element and a switch element. The inductance element has at least one first winding and one second winding and the first winding is connected to the second winding in series. The controller IC is electrically connected to the inductance element and the switch element. The external DC voltage is converted into at least one power voltage according to a turn ratio between the first winding and the second winding, thus supplying power to the controller IC to control the switch element.

Abstract: There is provided a power supply device including an alternating current (AC) power supply unit supplying a first primary current in a positive half cycle and supplying a second primary current in a negative half cycle; a transformer unit including a first transformer and a second transformer; a main switch unit including a first main switch and a second main switch; an auxiliary switch unit including a first auxiliary switch and a second auxiliary switch; an auxiliary inductor unit including a first auxiliary inductor and a second auxiliary inductor; and a path providing unit providing a conduction path based on power supplied from the AC power supply unit.

Abstract: A DC-DC converter includes a primary side sense circuit to detect a load current of the DC-DC converter based on reflected current from a secondary winding of the DC-DC converter to a primary winding of the DC-DC converter. A primary side diode models effects of a secondary side diode that is driven from the secondary winding of the DC-DC converter. An output correction circuit controls a switching waveform to the primary winding of the DC-DC converter based on feedback from the primary side sense circuit and the primary side diode.

Abstract: A bidirectional DC/DC converter includes a bidirectional DC/AC conversion circuit including a push-pull circuit connected between voltage terminals and a winding and having a switching element and a switching element coupled to opposing ends of the winding respectively, and an up-conversion circuit coupled to the push-pull circuit and the voltage terminals, and the up-conversion circuit includes an inductor for allowing passage of a current through the winding, the switching element in an ON state and the switching element in an ON state owing to stored magnetic energy, and a switching element forming a current path going through the voltage terminal, the inductor and the voltage terminal but not through the switching element and the switching element as it is turned on.

Abstract: A semiconductor device having a JFET and diode, includes a substrate, a second well region, and a second doped region that are of a first conductivity type. The JFET also includes a first well region, a first doped region, and a shared region that are of the second conductivity type. The second well region is disposed in the substrate adjacent to the first well region. A source of the JFET includes the first doped region disposed in the first well region. An anode of the diode includes the second doped region disposed in the second well region. Both a drain of the JFET and a cathode of the diode include the shared region disposed in the first well region. A diode current flows along a first lateral axis of the device while a JFET current flows along a second lateral axis of the device.

Abstract: A power supply device includes a first semiconductor switching device for controlling an alternating input current waveform, a smoothing capacitor to which a rectified voltage is applied, and an inverter that converts the rectified voltage into alternating current via a step-up chopper. The step-up chopper includes an inductor and a diode connected between the smoothing capacitor and inverter, and a second semiconductor switching device connected to the inductor and diode. The power supply device further includes an instantaneous voltage drop compensation function whereby the energy of the smoothing capacitor is supplied by an operation of the step-up chopper to the inverter when there is an instantaneous voltage drop in an alternating current power supply voltage. MOSFETs with a breakdown voltage lower than that of the first semiconductor switching device are connected between terminals of the step-up chopper, thus further reducing loss in comparison with when a bypass diode is used.

Abstract: A modified power converter circuit utilizes an RLC circuit tuned to the frequency of any instability in the power converter circuit in order to remove the instability in the circuit output. In one embodiment, a pair of RLC circuits are connected in parallel across the input capacitor and output capacitor of the power circuit topology, respectively. The capacitor and inductor of each RLC circuit act as filters having a period with the same value as the instability created by interaction of the respective input or output capacitor with the isolation transformer inductance and expose the resistor within each the RLC circuit to only the frequency of instability.

Abstract: A DC/DC converter is coupled between a DC source and a load. The DC/DC converter includes a first charge pump circuit coupled to the DC source, a second charge pump coupled to the load, a first switch coupled to the first charge pump circuit, a second switch coupled to the second charge pump circuit, and a first inductor, wherein, one terminal of the first inductor coupled to the first charge pump circuit and the second charge pump circuit, and the other terminal coupled to a common node between the first switch and the second switch. And wherein, the first inductor, the first switch and the second switch are configured between the first charge pump and the second charge pump.

Abstract: A controller for use in a power converter includes logic circuits to turn on and off a switch to regulate an output quantity. A first integrating capacitor is charged with a combination of a first current and a second current while the switch is turned on. The first current is proportional to a reset voltage and the second current is proportional to an input voltage. A reference generation circuit including a second integrating capacitor is charged with the first current during a previous switching cycle of the switch. The reference generation circuit generates a reference voltage in response to the second integrating capacitor. A comparator provides a stop signal to the logic circuits to turn off the switch in response to a comparison of a voltage across the first integrating capacitor with the reference voltage.

Abstract: Forward boost power converters, and related methods, are disclosed. In a switching mode power converter coupled between a first terminal pair and a second terminal pair, a first inductance is coupled to a first switch in a first circuit path across the first terminal pair. A capacitance is coupled to a second inductance in a second circuit path, and to the first inductance in a third circuit path. During their respective conduction periods, the first switch couples the first inductance across the first terminal pair, a second switch completes a circuit between the second terminal pair and one of: the second circuit path or the third circuit path, and a third switch completes the other of: the second circuit path and the third circuit path. Energy transfer involves both substantially linearly varying currents and substantially half sinusoidal current pulses.

Abstract: A power converter including an inductor-inductor-capacitor stage and method of operating the same. In one embodiment, the power converter includes an inductor-inductor-capacitor (LLC) stage coupled to an input of said power converter. The power converter also includes a controller configured to control a switching frequency of the LLC stage as a function of an input voltage of the power converter.

Abstract: The present invention discloses circuits and methods for high efficiency and fast response AC-DC voltage converters. In one embodiment, an AC-DC voltage converter can include: (i) a first stage voltage converter having an isolated topology with a power factor correction function, where the first stage voltage converter is configured to convert an AC input voltage to a series-connected N branches of first stage voltages, where N is a positive integer of at least two; (ii) a second stage voltage converter having a non-isolated topology, where the second stage voltage converter is configured to convert one of the N branches of the first stage voltages to a second stage voltage; and (iii) where the second stage voltage and a remaining of the N branches of the first stage voltages are configured to be series-connected and converted to a DC output voltage.

Abstract: Disclosed is a test apparatus for measuring the common-mode parasitic capacitance between a first element and a second element being isolated from the first element. The test apparatus includes a signal generating device connected to the first element and having an internal signal source connected in series with a first internal impedance for sending a signal to the first element, and a signal receiving device connected between the second element and the first element and having a second internal impedance for measuring a signal response between the first element and the second element, thereby calculating the common-mode capacitance between the first element and the second element based on the signal response.

Abstract: A variable frequency converter and an adjusting method for the same are provided in the present application. The variable frequency converter operates in a variable frequency mode, and comprises a power stage circuit module and a variable frequency signal stage circuit module which are connected to form a closed-loop circuit system. The variable frequency converter further comprises an adjusting unit outputting a continuous interfering signal and loading the continuous interfering signal into the variable frequency signal stage circuit module so as to cause operating frequency of the power stage circuit module controlled by the variable frequency signal stage circuit module to change continuously. In the present application, in the variable frequency converter, the EMI peak value is decreased.

Abstract: In the present invention, switching circuits connected in middle points of power supply lines of a three-phase alternating-current power supply are switched to cause currents to intermittently flow on primary windings of a transformer, a voltage generated on a secondary winding is rectified and smoothed, and then is outputted to a load. The switching circuits each include: a series circuit including a first primary winding, a bidirectional switch and a second primary winding, which are connected in series in this order; a drive circuit power supply generating circuit generating a direct-current positive voltage and a direct-current negative voltage by use of an alternating-current power supply voltage applied between two ends of the series circuit; and a drive circuit performing on-off drive of the bidirectional switch. A reference potential point of the bidirectional switch is connected to a reference potential point of the drive circuit power supply generating circuit.

Abstract: A switch mode power supply having an output terminal configured to provide an output voltage, the switch mode power supply has a first switch and a control circuit, wherein the control circuit is configured to receive a current sense signal via a reuse input pin when the first switch is turned ON, and the control circuit is configured to receive a voltage sense signal via a reuse input pin when the first switch is turned OFF.

Abstract: A voltage converting apparatus and a sub-harmonic detector are disclosed. The sub-harmonic detector includes a pulse eliminating circuit, a counter, and a comparator. The pulse eliminating circuit receives a pulse width modulation (PWM) signal and a reference PWM signal having a same period. The PWM signal and reference PWM signal has a plurality of pulses and reference pulses respectively. The pulse eliminating circuit eliminates at least one part of the pulses which overlap with the reference pulses for generating a processed signal. The counter counts the processed signal and the PWM signal during a time period to obtain first and second counting values. The comparator compares the first and second counting values for detecting whether a sub-harmonic condition happens or not in the PWM signal.

Abstract: A disconnect device for a switched-mode power supply, including an activation device for a first transistor for generating a transformable voltage. The device includes a second transistor of the PNP type and a third transistor of the NPN type, the base of the second transistor being connected to the collector of the third transistor and the base of the third transistor being connected to the collector of the second transistor. The emitter of the third transistor is connected to ground. The emitter of the second transistor is connected to a control voltage terminal of the activation device, the control voltage terminal being configured for suppressing the generation of the voltage by the first transistor, if the control voltage terminal is connected to ground, so that the generation of the voltage is suppressed if the base of the third transistor is acted upon by a voltage exceeding a predetermined threshold value.

Abstract: Aspects of the disclosure provide a method. The method includes determining a power adjustment to a load, determining whether a switching frequency of a pulse width modulation (PWM) signal is within a specific range, and adjusting the switching frequency of the PWM signal based on the power adjustment to control power transfer to the load. The switching frequency is adjusted to remain in the specific range.

Abstract: A snubber circuit comprises a first energy storage device and circuitry coupled to the first energy storage device to facilitate capturing, by the first energy storage device, energy of a switching circuit. The snubber circuit also comprises a second energy storage device coupled to the first energy storage device to store the captured energy. The circuitry additionally facilitates resetting of the first energy storage device.

Abstract: The present invention relates to a near zero current-ripple inversion circuit including top and bottom cells, a transformer (T1) comprising primary windings (P1, P2) and a secondary winding (S1), and at least one middle cell connected in series between the top and bottom cells. The top cell comprises two capacitors (C1, C2) and a switch (Q1) each connecting to the middle cell, and an inductor (Lr1) and the primary winding (P1) connected in series between the capacitor (C1) and switch (Q1), wherein the switch (Q1) is connected to the capacitors (C1, C2) respectively. The bottom cell comprises a capacitor (C3) and a switch (Q2) each connecting to the middle cell, and an inductor (Lr2) and the primary winding (P2) connected in series between the capacitor (C3) and switch (Q2), wherein the primary winding (P2) is connected to the middle cell, and the capacitor (C3) and switch (Q2) are connected.

Abstract: A controller for controlling power to a light source includes a first sensing pin, a second sensing pin, a third sensing pin, and a driving pin. The first sensing pin receives a first signal indicating an instant current flowing through an energy storage element. The second sensing pin receives a second signal indicating an average current flowing through the energy storage element. The third sensing pin receives a third signal indicating whether the instant current decreases to a predetermined current level. The driving pin provides a driving signal to a switch to control an average current flowing through the light source to a target current level. The driving signal is generated based on one or more signals selected from the first signal, the second signal and the third signal.

Abstract: A high-efficiency high step-up ratio direct current converter with an interleaved soft-switching mechanism is provided. The direct current converter includes a voltage-multiplier circuit and an active clamping circuit. The voltage-multiplier circuit includes two isolating transformers, two main switches disposed on a primary side of the two isolating transformers, four diodes disposed on a secondary side of the two isolating transformers and four capacitors disposed on the secondary side of two isolating transformers, configured to boost a voltage of a direct-current power to a desired voltage value. The active clamping circuit, electrically connected to the voltage-multiplier circuit, includes two active clamp switches and a clamp capacitor to lower a voltage surge of the two main switches so that the two main switches and the two active clamp switches can be soft switched on.

Abstract: A method of controlling a switching mode power converter enables zero voltage switching by forcing a voltage across the main switch to zero. This is accomplished by sensing when a current on the secondary side of the power converter drops to zero, or other threshold value, and then generating a negative current through the secondary winding in response. The negative secondary current results in a corresponding discharge current in the primary winding, which reduces the voltage across the main switch. The voltage across the main switch is monitored such that when the voltage reaches zero, or other threshold value, the main switch is turned ON. In this manner, the circuit functions as a bi-directional current circuit where a forward current delivers energy to a load and a reverse current provides control for reducing the voltage across the main switch to enable zero voltage switching.

Abstract: Embodiments of an adapter are disclosed that include a rectifier with an input and an output coupled to a step-down transformer with a primary coil and a secondary coil, wherein the primary coil is coupled to the output of the rectifier. A step-up converter is coupled to the secondary coil.

Abstract: An inverter device includes: an inverter circuit configured to perform ON/OFF operations with a preset duty cycle to convert a DC power into an AC power and output the AC power to an AC motor; and a controller configured to change a duty cycle of the ON/OFF operations.

Abstract: An apparatus for generating an isolated power supply voltage and an isolated data signal includes a first pulse generation circuit configured to generate a first pulse signal and a second pulse generation circuit configured to generate a second pulse signal based on an input pulse width modulation (PWM) signal. A transformer circuit including a transformer is coupled to the first pulse generation circuit and to the second pulse generation circuit. The transformer is configured to generate an output pulse signal based on the first pulse signal and the second pulse signal. An isolated power supply circuit is coupled to the transformer circuit and is configured to generate an isolated power supply voltage based on the output pulse signal. A latch circuit is coupled to the transformer circuit and is configured to generate an isolated PWM signal based on the output pulse signal.

Abstract: In a DC/DC converter that performs zero-voltage switching, capacitors are connected respectively in parallel to first and second MOSFETs that are included in an inverter unit in the primary-side of a transformer, and an inductor is connected to an AC output line. In a range of a current being more than a predetermined value, a control circuit controls the inverter unit using a PWM control with a fixed dead time, and in a light load range where the current is equal to or less than the predetermined value, the control unit changes the control to a PFM control and decreases a frequency so that the dead time becomes longer as the current decreases, to thereby keep a duty ratio without change.

Abstract: A power conversion apparatus is disclosed. The power conversion apparatus includes a power transistor, a thermal resistor and a temperature detection circuit. A control terminal of the power transistor receives a control signal. The power transistor converts an input voltage into an output voltage according to the control signal. The thermal resistor has a negative temperature coefficient. The temperature detection circuit generates the control signal and provides a driving current to the control terminal of the power transistor according to the control signal. The temperature detection circuit further generates an over temperature protection signal according to the driving current.

Abstract: The present application provides a synchronous rectifying apparatus and a control method thereof, the apparatus comprising: a transformer, a primary circuit, a rectifying circuit, a self-driving circuit, a PWM control circuit and an auxiliary control module including at least one auxiliary control circuit and at least one auxiliary winding, wherein the auxiliary control circuit includes at least one auxiliary switch and is electrically coupled to the Pulse Width Modulation control circuit and the auxiliary winding via the auxiliary switch, and the auxiliary winding is electrically coupled to the transformer; wherein before the transfer switch of the primary circuit is controlled to be turned on by the switching control signal, the auxiliary switch is controlled to be turned on by the auxiliary control signal, and the synchronous rectifier of the rectifying circuit is controlled to be turned off through the self-driving signal.

Abstract: A compound semiconductor device includes: a compound semiconductor multilayer structure including a first buffer layer composed of AlN; and a second buffer layer composed of AlGaN and formed above the first buffer layer, wherein the second buffer layer contains carbon, and wherein the concentration of carbon in the second buffer layer increases with increasing distance from a lower surface of the second buffer layer toward an upper surface of the second buffer layer.

Abstract: A power converter system, method and device powers a load when coupled to the load and draws a quasi-zero amount of power from the power supply when not coupled to the load. The power converter system maintains an output voltage such that the power converter system is able to properly “wake-up” when a load is coupled by intermittently operating the power converter for a preselected number of cycles when it is detected that the output voltage has fallen below a threshold level.

Abstract: A compound semiconductor device includes: a compound semiconductor layer; a protective insulating film that covers a top of the compound semiconductor layer; and a gate electrode formed on the protective insulating film, wherein the protective insulating film has a first trench and a second trench which is formed side by side with the first trench and in which the protective insulating film remains with only a predetermined thickness on the compound semiconductor layer, and wherein the gate electrode fills the first trench, and one end of the gate electrode is away from the first trench and located at least in the second trench.