Abstract: An LLC resonant converter and an electronic device are provided. The LLC resonant converter according to the present disclosure includes a multi input transformer, first and second converter units connected to a primary side of the multi input transformer, an input voltage part, a first balance capacitor, and an output part connected to a secondary side of the multi input transformer.

Abstract: Various embodiments of devices, systems, and methods for regulating the output current of a switched mode, resonant power converter using primary side regulation. For at least one embodiment, a circuit for primary side regulation of a constant output current resonant transformer includes a transformer having a first coil with a first terminal and a second terminal. A controller circuit is configured to receive an input voltage and a resonant circuit is coupled to the controller circuit and the first terminal. A current sense circuit is coupled to the second terminal and to the controller circuit. The current sense circuit is configured to detect fluctuations in a sensed resulting voltage potential representative of the output current of the transformer. The current sense circuit is configured to provide a feedback signal to the controller circuit when the sensed resulting voltage potential is greater than a reference voltage.

Abstract: A power delivery system wirelessly delivers electric power and a communication signal to a target device. The power delivery system includes a power transmitting unit having a power source operable to source alternating current power and a sending resonant coupling component operable to couple the alternating current power to a coil for wireless power transmission by a non-radiated magnetic field at a target resonant frequency. The power transmitting unit is capable of dynamically tuning the wireless power transmission to the target resonant frequency wherein the target resonant frequency is specified dynamically. A communication module couples to the power transmitting unit and is operable to couple the communication signal to the non-radiated magnetic field. Operations may include target device authentication, target resonant frequency information communication, billing, and device management.

Abstract: A microwave generator includes a power supply, an output circuit, a feedback oscillator, a pulse controller, a signal combination circuit and a semiconductor amplifier. The power supply converts input voltage and input current into output voltage and output current. The output circuit generates a microwave signal to an output terminal of the microwave generator and a feedback signal according to the microwave signal. The feedback oscillator generates an oscillation signal according to the feedback signal. According to a reference signal, the pulse controller generates a pulse signal. According to the oscillation signal and pulse signal, the signal combination circuit generates a control signal. The semiconductor amplifier generates and adjusts an amplified signal according to the control signal. The output circuit generates the microwave signal according to the amplified signal. The output current is adjusted according to the amplified signal.

Abstract: A wireless power transmitting apparatus wirelessly charging a wireless power receiving apparatus is provided. The wireless power transmitting apparatus includes a power providing unit configured to provide power, a gate driver configured to generate a differential signal formed of a first signal and a second signal from the power provided from the power providing unit, an amplifier configured to amplify the differential signal by a predetermined gain, a power transmitting unit configured to transmit the amplified differential signal to the wireless power receiving apparatus, and a differential signal correcting circuit that is disposed between the gate driver and the amplifier and is configured to correct the differential signal so that a predetermined phase difference between the first signal and the second signal is maintained.

Abstract: An inductive power transfer (IPT) control method is disclosed for controlling the output of an IPT pick-up. The invention involves selectively shunting first and second diodes of a diode bridge to selectively rectify an AC current input for supply to a load, or recirculate the AC current to a resonant circuit coupled to the input of the controller. By controlling the proportion of each positive-negative cycle of the AC input which is rectified/recirculated, the output is regulated. Also disclosed is an IPT controller adapted to perform the method, an IPT pick-up incorporating the IPT controller, and an IPT system incorporating at least one such IPT pick-up.

Abstract: A circuit and a corresponding method for driving one or more electric loads are described, comprising: a generator (110) of an electric current waveform, and a passive filter (150) connected in input to the generator (110) and in output to each electric load (105) to be driven, wherein the passive filter (150) is tuned for generating an electric current waveform resulting from a conditioning of one or more harmonics of the electric current waveform in input.

Abstract: An LLC resonant converter controller comprising an overcurrent protection circuit coupled to receive a current sense signal representative of current in a primary winding, wherein the overcurrent protection circuit outputs an overcurrent signal when the perturbed current sense signal is above a low threshold for a number of consecutive switching cycles. The LLC resonant converter controller further includes a control circuit coupled to generate a high side drive signal and a low side drive signal in response to a feedback signal representative of an output of an LLC resonant converter is further coupled to receive the overcurrent signal and is operable to disable switching of the first power switch and second power switch in response to the overcurrent signal.

Abstract: Provided are a charging system, a protection method and a power adapter. The charging system comprises: a battery, a first rectification unit, a switch unit, a transformer, a second rectification unit), a voltage sampling circuit, a control unit, and a comparator unit. The first rectification unit outputs the voltage with the first pulsating waveform. The switch unit outputs the modulated voltage with the first pulsating waveform. The transformer outputs the voltage with the second pulsating waveform. The second rectification unit outputs the voltage with the third pulsating waveform. The control unit adjusts a duty cycle of a control signal, such that the voltage of a third pulsation waveform meets the charging requirement of the battery. The comparator unit applies a comparison signal to the switch unit when the voltage sampling value is greater than the reference voltage value, so as to control the switch unit to forcibly open.

Abstract: A multiple parallel-connected resonant converter, an inductor-integrated magnetic element and a transformer-integrated magnetic element are provided. The multiple parallel-connected resonant converter includes a first and a second converters. The first converter having a first input and output end includes a first inductor, a first transformer and a first capacitor connected in series. The second converter having a second input and output end includes a second inductor, a second transformer and a second capacitor connected in series. The second output end is connected with the first output end in parallel. The first and second inductor are integrated in a first magnetic element, the first magnetic element includes a first and second side column, and a first and second central column. The first inductor includes a first coil positioned around the first central column and the second inductor includes a second coil positioned around the second central column.

Abstract: According to some aspects of the present disclosure, switched-mode power converters and control methods are disclosed. Example power converters include an input terminal, an output terminal, and a transformer coupled between the input terminal and the output terminal. The transformer includes a primary winding and a secondary winding. The power supply also includes at least one switch coupled to the primary winding, and a primary controller coupled to the at least one switch to control switching operation of the at least one switch. The primary controller includes a voltage reference. The power supply further includes a secondary controller configured to detect a no load condition at the output terminal, and operate the primary controller in a burst mode by adjusting the voltage reference of the primary controller when the secondary controller detects the no load condition at the output terminal.

Abstract: A synchronous rectification controller includes a first gate pin coupled to a gate of a first synchronous rectification transistor, a first drain pin coupled to a drain of the first synchronous rectification transistor, a second gate pin coupled to a gate of a second synchronous rectification transistor, a second drain pin coupled to a drain of the second synchronous rectification transistor, a source pin coupled to a ground, a multiplexer selecting a voltage applied to the first drain pin in a first state, and selecting a voltage applied to the second drain pin in a second state, a pulse generator generating a pulse signal based on an output voltage of the multiplexer, a driving circuit switching the first synchronous rectification transistor according to the pulse signal in the first state, and switching the second synchronous rectification transistor according to the pulse signal in the second state.

Abstract: The present disclosure discloses a charging system, a charging method, and a power adapter. The charging system includes a battery, a first rectifier, a switch unit, a transformer, a second rectifier, a sampling unit, and a control unit. The control unit outputs a control signal to the switch unit, and adjusts a duty ratio of the control signal according to a current sampling value and/or voltage sampling value sampled by the sampling unit, such that a third voltage with a third ripple waveform outputted by the second rectifier meets a charging requirement of the battery.

Abstract: An electric power converter includes a chopper circuit, a DC-DC converter coupled to an output of the chopper circuit, a first transformer including a first primary coil and a first secondary coil, a second transformer including a second primary coil and a second secondary coil, a first capacitor coupled between an output of the DC-DC converter and the first primary coil, a second capacitor coupled between the output of the DC-DC converter and the second primary coil, a first rectifier circuit coupled to the first secondary coil, and a second rectifier circuit coupled to the second secondary coil. A first output voltage of the first rectifier circuit is adjusted by adjusting an output voltage of the chopper circuit, and a second output voltage of the second rectifier circuit is adjusted by adjusting a powering time during one switching period of the DC-DC converter.

Abstract: A display apparatus is provided. The display apparatus includes a display configured to display an image, an image signal provider circuit configured to provide an image signal to the display, and a power supply configured to generate driving power and to supply the generated driving power to the image signal provider, wherein the power supply controls an operation time of a power factor compensation (PFC) circuit which performs power factor compensation of the display apparatus based on a size of an output load receiving the driving voltage.

Abstract: The switching power supply device includes switching circuits, a transformer, an LLC resonance circuit, a microcomputer and a frequency regulator that sets switching frequencies of the switching circuits and a current detection circuit that detects the current Ir. The microcomputer and the frequency regulator sweep a switching frequency, and set a switching frequency on the basis of times to start the dead times of the switching elements, the current Ir detected by the current detection circuit, and the threshold current Imin.

Abstract: The power supply apparatus includes a control unit configured to perform control of gradually changing a turn-on duty of a first switching element when a first voltage mode is switched to a second voltage mode or when the second voltage mode is switched to the first voltage mode.

Abstract: In some implementations, a programmable power adapter includes a first set of switches, a resonant circuit, a transformer, and a second set of switches. The power adapter includes control circuitry configured to provide control signals that change the voltage conversion ratios of the first set of switches and the second set of switches. The control circuitry can provide control signals causing the first set of switches to operate in one of multiple operating modes that each correspond to a different voltage conversion ratio, and the control circuitry can provide control signals causing the second set of switches to operate in one of multiple operating modes that each correspond to a different voltage conversion ratio.

Abstract: A converter circuit is disclosed. The converter circuit includes a transformer and a primary circuit connected to the primary side of the transformer, where the primary circuit includes a first switch connected to a ground. The converter circuit also includes a second switch connected to the first switch, and a clamping capacitor connected to the second switch and to the input. The converter circuit also includes a secondary circuit connected to the secondary side of the transformer, where the secondary circuit includes a rectifying element, and an output capacitor connected to the rectifying element. In addition, the output capacitor has a substantial effect on resonance of the converter circuit.

Abstract: A switching power supply device having a synchronous rectifier IC on a secondary side, responds to an anomaly on a primary side based on detecting an occurrence of the anomaly on the secondary side. When a secondary side synchronous rectifier IC detects an anomaly, a current is output from the anomaly-time current output terminal of the secondary side synchronous rectifier IC. By the output current flowing through a resistance, a voltage at an output voltage detection point is raised to increase a current through the cathode of a shunt regulator. In so doing, a current flowing through a photodiode of a photocoupler also increases, and the FB terminal voltage of a switching control IC connected to a primary side phototransistor decreases. The primary side switching control IC operates to minimize output power, reduces a secondary side output voltage, or stops an operation of the switching power supply device.

Abstract: Resonant power converters that replace the conventional impedance matching stage with series or parallel connections between resonant inverters and resonant rectifiers are provided. Two or more resonant rectifiers can be connected in series or in parallel to the resonant inverter to provide impedance matching. Similarly, two or more resonant inverters can be connected in series or in parallel to the resonant rectifier to provide impedance matching. Electrical isolation of DC voltage between input and output is provided using only capacitors.

Abstract: Disclosed examples include battery apparatus and balancing circuits for transferring charge between one or more of a plurality of battery cells and a second battery, in which a battery is coupled with a first winding of a transformer, and the second battery is coupled with a second transformer winding. A first transistor is turned on to allow current flow in the first winding to discharge the first battery, and then the first transistor is turned off. The resulting induced voltage in the second winding turns on a second transistor to provide flyback active charge balancing to charge the second battery. A signal from the third winding allows detection of low or zero current flow in the second winding for a controller to begin subsequent charge transfer cycles for full isolation between the first and second batteries.

Abstract: A switch control circuit includes a first pin connected to a first voltage, and a second pin connected to another end of a first resistor including an end connected to the first pin and a first capacitor. In the switch control circuit, at least two of first dead time information, second dead time information, and a protection mode are set by using a multi-voltage of the second pin. The first dead time information is information about a dead time of a first switch and a second switch controlling power supply, the second dead time information is information about a dead time for synchronous rectification, and the protection mode includes an auto-restart mode and a latch mode.

Abstract: In an Input-Series-Output-Parallel (ISOP)-type power converter circuit, a DC-to-DC converter has a positive input coupled to a DC power source and a negative input connected to a negative output. A plurality of capacitors are coupled in series between a positive output of the converter and a circuit ground, the negative output of the converter coupled to a common node of first and second capacitors. A half-bridge inverter network is coupled between the positive output and a circuit ground, each inverter having an input respectively coupled to the first capacitor and the second capacitor. A plurality of resonant tanks are coupled to an output of a respective one of first and second half-bridge inverters. A transformer is coupled to outputs of the plurality of resonant tanks. A rectifier circuit is coupled to a secondary winding of the transformer to provide a DC output voltage.

Abstract: A power converter controller includes a high side signal interface circuit that includes a common mode cancellation circuit that is coupled to generate a fourth current signal representative of an OFF signal referenced to a bypass voltage during an initial state, and a first current signal in response to an ON signal being pulled to a lower value relative to the OFF signal to turn ON a high side switch. The common mode cancellation circuit generates a common mode rejection signal in response to the first and fourth current signals. A first current hysteresis comparator receives the first and fourth current signals, the common mode rejection signal, and a drive signal to generate a first output signal. A drive signal generated in response to the first output signal in a presence of a common mode voltage caused by slewing at a half bridge node.

Abstract: According to an implementation, a resonant converter for resonant capacitance stabilization during start-up includes an oscillator configured to generate a first clock signal to drive a first driver for a first power switch, and a second clock signal to drive a second driver for a second power switch during switching operations, and a resonant capacitor stabilizer configured to control the second driver to periodically activate the second power switch to discharge a resonant capacitor of a resonant network during initialization of the switching operations of the resonant converter.

Abstract: A resonant converter includes a first resonant conversion circuit, a second resonant conversion circuit, and a control unit. The first resonant conversion circuit has a first switch element and a second switch element, and the first switch element is ungrounded coupled to the second switch element and the second switch element is grounded. The second resonant conversion circuit has a third switch element and a fourth switch element, and the third switch element is ungrounded coupled to the fourth switch element and the fourth switch element is grounded. The control unit receives a feedback signal and controls the first resonant conversion circuit and the second resonant conversion circuit according to the feedback signal. Accordingly, it is to simplify circuit controls and increase the dynamic performance of phase controls.

Abstract: A wireless power transmission/reception system includes a wireless power transmission circuit and a wireless power reception circuit. The wireless power transmission circuit includes an oscillator, a DC-AC converter that converts a direct current to an alternating current and is turned on/off in response to a control signal, a power transmission coil that transmits AC power, a signal reception coil, and a signal receiver that transfers the control signal to the DC-AC converter. The wireless power reception circuit includes a power reception coil, a rectifier that converts an alternating current to a direct current and is turned on or off in response to the control signal, an control signal generator that generates the control signal, a signal transmission coil, and a signal transmitter that transmits the control signal through the signal transmission coil.

Abstract: A converter is provided. The converter includes a first DC/DC converter, a non-isolated DC/DC converter and a control circuit. The first DC/DC converter includes a transformer, a primary side inverter and a secondary side rectifier. The primary side inverter and a secondary side rectifier are operable at multiple operating modes. The control circuit determines an operating mode for the primary side inverter or the secondary side rectifier, and controls the primary side inverter or the secondary side rectifier to change its respective operating mode.

Abstract: A power supply device includes a rectifying unit for rectifying an AC input voltage, a voltage conversion unit including a switching element and configured to receive a rectified input voltage from the rectifying unit and obtain an output voltage voltage-converted by a switching operation of the switching element, and a voltage comparison unit configured to generate a comparison signal between the output voltage and a set output voltage. The power supply device further includes an oscillation unit configured to output a control signal having an oscillation period and an oscillation-stop period as a control signal for controlling an ON/OFF of the switching element. The oscillation period and the oscillation-stop period of the control signal are controlled by the comparison signal outputted from the voltage comparison unit, and a pulse duty ratio of the control signal in the oscillation period is variably controlled based on the input voltage.

Abstract: An AC-to-DC converter includes a multi-resonant switching circuit including an AC-AC stage soft-switched LC network that converts a low-frequency low-amplitude alternating input voltage into a higher-frequency higher-amplitude alternating voltage and an AC-DC stage rectifying the higher-frequency higher-amplitude alternating voltage into a DC output voltage via a soft-switched diode. An AC-to-DC converter system includes at least two multi-resonant switching circuits that include at least two AC-AC stages and an AC-DC stage. A control system for the AC-to-DC converter includes at least two resonant gate drivers that each includes: one MOSFET gate configured to transmit a gate voltage signal to an AC-to-DC converter; an on/off logic module electrically coupled to the MOSFET gate; a resonant tank LC circuit electrically coupled to the on/off logic module; and a voltage bias module electrically coupled to the resonant tank LC circuit.

Abstract: A variable frequency resonant converter includes an inverter stage, a resonant circuit, a transformer, a rectifier stage, and a controller. The inverter and rectifier stages include first and second FET devices. The inverter converts a DC input signal to a first AC signal. The resonant circuit is coupled to the inverter stage and filters the first AC signal. The transformer is coupled to the resonant circuit and converts the first AC signal to a second AC signal. The rectifier stage is coupled to the transformer and converts the second AC signal to a DC output signal. The controller is configured to operate both of the first and second FET devices substantially at a resonant frequency at least partially defined by the resonant circuit to generate the DC output signal according to a voltage setpoint.

Abstract: A driver circuit includes a first voltage converter, a light source driver, a second voltage converter and a control circuit. The first voltage converter converts a first voltage to a second voltage. The light source driver is coupled to the first voltage converter, converts the second voltage to a third voltage and outputs the third voltage to a light source for providing light. The second voltage converter is coupled to the first voltage converter, converts the second voltage to a fourth voltage and outputs the fourth voltage. The control circuit is coupled to the second voltage converter to receive the fourth voltage and outputs a first control signal to control the light source driver for controlling the light source. The first voltage is lower than the second voltage, the second voltage is higher than the third voltage, and the second voltage is higher than the fourth voltage.

Abstract: Disclosed are a wireless power transmitter and a power transmission method thereof. The wireless power transmitter includes a plurality of transmission resonance units, a detection power applying unit applying detection power to the transmission resonance units to detect a location of the wireless power receiver, and a current measuring unit measuring current generating from a transmission coil unit of the wireless power transmitter based on the applied detection power. The wireless power transmitter transmits the power through at least one transmitting resonance unit corresponding to the location of the wireless power receiver based on the measured current.

Abstract: A range calculator (12) calculates an operation value range, which is range of an operation value tor controlling a duty cycle of a chopper circuit (4) based on an input voltage and output voltage command value of the chopper circuit (4). A chopper circuit control device (1) controls the duty cycle of the chopper circuit (4) by using an upper limit value of the operation value range when an operation value is greater than or equal to the upper limit value of the operation value range, by using the operation value when the operation value is within the operation value range, and by using a lower limit value of the operation value range when the operation value is less than or equal to the lower limit value of the operation value range.

Abstract: A power switching apparatus includes a detection circuit, a control circuit and an auxiliary power circuit. The detection circuit comprises a voltage adjusting unit, a delay unit, a first switch unit and an isolation unit. The auxiliary power circuit comprises an auxiliary power input side and an output side. When a main power supplies power normally or the main power stops supplying power but the delay unit continues working in a setting time, the first switch unit is turned on. The isolation unit sends a first signal to the control circuit. The auxiliary power input side does not conduct to the output side. When the main power stops supplying power and the delay unit stops working, the first switch unit is turned off. The isolation unit does not send the first signal to the control circuit. The auxiliary power input side conducts to the output side.

Abstract: A controller for use in a power converter includes a control circuit coupled to generate a low side drive signal to control switching of a low side switch, and generate an ON signal and an OFF signal in response to a feedback signal representative of an output of the power converter. A high side signal interface circuit is coupled to generate a high side drive signal in response to the ON signal and the OFF signal to control switching of a high side switch. The ON signal and the OFF signal are coupled to be pulled up in response to a bypass voltage during an initial state. The high side signal is coupled to turn on the high side switch in response to the control circuit pulling the ON signal low, and turn off the high side switch in response to the control circuit pulling the OFF signal low.

Abstract: A controller for a resonant converter, the resonant converter comprising a first switch and a second switch. The controller configured to: close the first switch to start a half cycle of operation; open the first switch before completion of the half cycle; maintain the first switch and the second switch in an open state in order to define a stop-interval; and end the stop-interval by closing the second switch.

Abstract: A burst oscillation circuit operates switches in a burst oscillation mode based on a feedback signal. A first burst operation cancellation threshold voltage comparator compares a first burst operation cancellation threshold voltage set higher than a voltage of the feedback signal that a load current reaches the standby threshold and a voltage of the feedback signal, and outputs a first output signal. A second burst operation cancellation threshold voltage comparator compares a second burst operation cancellation threshold voltage set lower than the voltage of the feedback signal that the load current reaches the standby threshold and higher than a voltage of the feedback signal during a non-oscillation period of the burst oscillation operation and the voltage of the feedback signal and outputs a second output signal. A standby cancellation circuit generates a standby cancel signal to cancel the standby state based on the first and second output signal.

Abstract: A power conversion circuit uses a multiphase AC power source as an input and has a plurality of bidirectional switches each of which is connected to each phase of the multiphase AC power source. A switching control circuit controls the states of the plurality of bidirectional switches and switches a combination of two phases of the multiphase AC power source, relating to interphase voltage to be outputted from the power conversion circuit to a load side. A resonant circuit is connected to an output side of the power conversion circuit. The switching control circuit, at a time of switching of the combination of the two phases that output the interphase voltage to the load side, switches the states of the bidirectional switches relating to the switching, by soft switching.

Abstract: A converter circuit is disclosed. The converter circuit includes a transformer and a primary circuit connected to the primary side of the transformer, where the primary circuit includes a first switch connected to a ground. The converter circuit also includes a second switch connected to the first switch, and a clamping capacitor connected to the second switch and to the input. The converter circuit also includes a secondary circuit connected to the secondary side of the transformer, where the secondary circuit includes a rectifying element, and an output capacitor connected to the rectifying element. In addition, the output capacitor has a substantial effect on resonance of the converter circuit.

Abstract: Control method and circuit for resonant converters with capacitive protection. When a resonant converter enters into a capacitive mode, a high-side switch and a low-side switch of the resonant converter are turned off. After the high-side switch and a low-side switch are turned off for N switching cycles, the high-side switch is turned on once a current sense signal flowing through a resonant inductor of the resonant converter is increased to a zero-crossing threshold during an ascent stage of the current sense signal, and the low-side switch is turned on once the current sense signal is decreased to the zero-crossing threshold during a descent stage of the current sense signal.

Abstract: An inductive power transfer (IPT) control method is disclosed for controlling the output of an IPT pick-up. The invention involves selectively shunting first and second diodes of a diode bridge to selectively rectify an AC current input for supply to a load, or recirculate the AC current to a resonant circuit coupled to the input of the controller. By controlling the proportion of each positive-negative cycle of the AC input which is rectified/recirculated, the output is regulated. Also disclosed is an IPT controller adapted to perform the method, an IPT pick-up incorporating the IPT controller, and an IPT system incorporating at least one such IPT pick-up.

Abstract: A power system includes DC-DC power conversion circuitry that has a first switch and a second switch on either side of a transformer, and the second switch is operates as a synchronous rectifier. Power transfer from a primary side to secondary side of the DC-DC power conversion circuitry is controlled by operating the first switch. A drive signal for the second switch is calculated based on a sensed transformer winding current, and operation of the second switch is controlled based on the drive signal.

Abstract: A resonant converter includes a primary stage having first and second switches coupled in series, a controller coupled to the first switch and the second switch to control operation thereof, a first transformer comprising a primary coil coupled to a node between the first and second switches, and a resonant inductor coupled to the primary coil of the first transformer. The resonant converter also includes a secondary stage having a second transformer formed of a primary coil coupled to the resonant inductor and a secondary coil comprising first and second coil sections, a third switch coupled to the first coil section of the secondary coil, and a fourth switch coupled to the second coil section of the secondary coil. A switch drive circuit is provided to drive the third and fourth switches for synchronous rectification, with the switch drive circuit comprising a secondary coil of the first transformer.

Abstract: A resonant rectifying device includes a transformer having a primary winding and a secondary winding, a primary-side circuit coupled to the primary winding of the transformer, and a secondary-side circuit coupled to the secondary winding of the transformer. The primary-side circuit includes a first field effect transistor (FET) and a second FET coupled in series between a voltage source and a ground, a capacitor, and an inductor. A first side of the capacitor is coupled to a point between the first and the second FETs. A second side of the capacitor is coupled to a first end of the inductor and one end of the primary winding. A second end of the inductor is coupled to the ground. The secondary-side circuit includes a third FET and a fourth FET coupled to a first end and a second end of the secondary winding, respectively.

Abstract: The present invention includes: a series circuit formed of a reactor Lr, a primary winding P of a transformer T, and a capacitor C2; a full-wave rectifier/smoothing circuit D1, D2, C3 configured to perform full-wave rectification and smoothing on a voltage generated in a secondary winding S of the transformer thereby to extract a DC voltage; a control circuit FF1 configured to set a first ON time of the first switch element Q1 and a second ON time of the second switch element Q2 to the same predetermined time thereby to alternately turn on and off the first switch element and the second switch element; and a first ON time controller I1, 16, C7 configured to set one of the first ON time and the second ON time, shorter than the predetermined time, under light-load conditions, based on the DC voltage detected by a detector 11.

Abstract: A universal power adapter includes a power converter configured to generate an output power based on a switching frequency of the power converter. The universal power adapter also includes a frequency controller operatively coupled to the power converter and configured to control the switching frequency of the power converter. The universal power adapter further includes a switch capacitor circuit having a plurality of capacitive elements, operatively coupled to the power converter. The switch capacitor circuit is configured to switch between the plurality of capacitive elements. The universal power adapter also includes a capacitance controller operatively coupled to the switch capacitor circuit and configured to control the switch capacitor circuit to control switching between the plurality of capacitive elements to maintain a control parameter within a threshold range of.

Abstract: In accordance with a preferred embodiment of the present invention, a method of operating a switch-mode power supply includes: receiving a dropout detection signal from a dropout detection circuit coupled to an input of the switch-mode power supply; and discharging an input capacitor coupled to the input of the switch-mode power supply via a switching transistor having a first load path coupled to the input capacitor through an inductive element.

Abstract: Disclosed is a power converter including a generator configured to generate a sequence of output voltage waveforms, a resonant tank connected to the generator comprising at least one capacitor and at least one inductor, a transformer including a primary side connected in series with said series inductor and, the primary side being configurable to use at least one primary winding tap and a secondary side for connecting to a rectifying circuit for providing a rectified DC voltage to an output load circuit, a first switch and a second switch on the primary side connected to the primary winding, wherein the at least one primary winding is selected by the first switch or the second switch to select a different reflected output voltage by closing the first switch or the second switch.