Abstract: Disclosed herein is a converter including a switching unit, an energy storage unit for storing energy from a direct current (DC) input voltage and then generating an output voltage according to a switching operation of the switching unit, and a switching controller for controlling the switching unit to selectively execute a first operation mode for turning on the switching unit at a fixed frequency or a second operation mode for turning on the switching unit when a voltage between one end and the other end of the switching unit reaches a zero point of a resonance waveform, wherein the switching controller includes an operation mode selection unit for selectively executing the first operation mode or the second operation mode according to whether the voltage between one end and the other end of the switching unit resonates.

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, I6, 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: An AC power converter converts power from an AC power source to an AC load. A DC power holding source is coupled to an input half-bridge switch, a common half-bridge switch and an output half-bridge switch. A controller is coupled to the input half-bridge switch, the common half-bridge switch, and an output half-bridge switch to generate at least two control signals at a common switching frequency, wherein the controller generates the at least two control signals with a phase difference there between chosen to cause a ripple frequency in both the input low pass filter and the output low pass filter to be double the common switching frequency. An input low pass filter can eliminate switching frequency energy from entering the AC power source. An output low pass filter can eliminate switching frequency energy from entering the AC load.

Abstract: The present invention discloses a power converter with synchronous control function and control method thereof. The power converter includes: a transformer, a power switch, a switch control unit, a signal coupling circuit, a synchronous rectifying switch and a secondary side control circuit. The switch control unit generates an operation signal according to a feedback signal, and generates a first synchronous signal which is related to the operation signal. The signal coupling circuit couples the first synchronous signal to generate a second synchronous signal. The synchronous rectifying switch is turned ON/OFF according to a synchronous rectifying switch signal, for synchronous rectification. The secondary side control circuit generates the synchronous rectifying switch signal according to a secondary side level detection signal and the second synchronous signal, to control the synchronous rectifying switch. The ON time of the power switch and the ON time of the synchronous rectifying switch do not overlap.

Abstract: A power delivery (PD) device includes: an AC/DC converter connected to an AC input, the AC/DC converter configured to change the AC input to a desired voltage value to be output in accordance with a first voltage changing control signal supplied from outside; and a DC/DC converter connected between an output of the AC/DC converter and a DC output, the DC/DC converter configured to change the output from the AC/DC converter to a desired voltage value to be output as a DC output in accordance with a second voltage changing control signal supplied from outside, wherein the AC/DC converter at a previous stage and the DC/DC converter at a subsequent stage are interlocked to change the output voltage to desired target voltage. There can be provided the PD device capable of delivering power with high power efficiency over the wide voltage ranges.

Abstract: A control circuit is used in a switching converter including at least, a switching transistor and a coil connected to the switching transistor. The control circuit includes: a current comparing circuit that asserts a peak current sensing signal when a current flowing in the coil during the ON period of the switching transistor reaches a threshold current. The current comparing circuit includes: a first comparator that compares a sensed voltage according to the current flowing in the switching transistor and the coil with a threshold voltage defining the threshold current, and generates a comparison signal; and a variable delay circuit that generates the peak current sensing signal by delaying the comparison signal, a delay amount of the variable delay circuit varying according to a period of time from a turn-on of the switching transistor to a transition of the comparison signal.

Abstract: A resonant converter includes a first switch on a primary side and a second switch coupled to the first switch, a first synchronous rectification switch on a secondary side conducted according to a switching operation of the first switch, a second synchronous rectification switch on the secondary side conducted according to a switching operation of the second switch, and a switch control circuit configured to detect a waveform of one end voltage of at least one of the first synchronous rectification switch and the second synchronous rectification switch, determine one of a below region and an above region, and differently control conduction duration of the first and second synchronous rectification switches according to a determined result.

Abstract: Control circuits with energy recycling for envelope elimination and restoration and related methods are disclosed. A control circuit includes a filter module configured to condition an input power signal to provide an output power signal. An energy recapture module is electrically coupled to the filter module and is configured to capture a portion of residual energy from the filter module and return the portion of the residual energy to the input power signal. A control module is electrically coupled to the filter module and the energy recapture module and is configured to control the filter module to provide the output power signal and is further configured to control the energy recapture module to capture and return the portion of the residual energy to the input power signal.

Abstract: A wireless power transmission apparatus for high efficiency energy charging, includes a resonator configured to transmit power, and a power supply unit configured to supply power to the resonator. The apparatus further includes a first switching unit configured to connect the resonator to the power supply unit, and disconnect the resonator from the power supply unit, and a controller configured to control the first switching unit based on an amount of current flowing into the resonator.

Abstract: A start-up method for a self-powered gate drive circuit driving a power transistor gate. The method comprises charging, with a single-supply voltage, a first supply capacitor of a first gate drive circuit; switching on a first power transistor by applying a current supplied by a discharge of the first supply capacitor of the first gate drive circuit to the gate of the first power transistor; charging a second supply capacitor of the first gate drive circuit using an output signal from the first power transistor; and re-charging the first supply capacitor by applying a current supplied by a discharge of the second supply capacitor to the first capacitor.

Abstract: This disclosure provides control techniques for a resonant converter. In one control technique, for switching speeds that are below the resonant frequency of the primary stage of the converter, the switches of the synchronous rectifier (SR) portion (SR switches) of the resonant converter are controlled based on a rising edge of the corresponding primary side switch and the turn off time of a corresponding SR switch. In general, for below resonance operation, each corresponding SR switch will be turned off prior to the falling edge of each corresponding primary side switch, while each corresponding SR switch will be turned on at the rising edge of the each corresponding primary side switch. The conduction time of respective SR switches is generally constant for below resonance operation.

Abstract: System and method are provided for protecting a power converter. The system includes a first comparator, and an off-time component. The first comparator is configured to receive a sensing signal and a first threshold signal and generate a first comparison signal based on at least information associated with the sensing signal and the first threshold signal, the power converter being associated with a switching frequency and further including a switch configured to affect the primary current. The off-time component is configured to receive the first comparison signal and generate an off-time signal based on at least information associated with the first comparison signal. The off-time component is further configured to, if the first comparison signal indicates the sensing signal to be larger than the first threshold signal in magnitude, generate the off-time signal to keep the switch to be turned off for at least a predetermined period of time.

Abstract: System and method are provided for protecting a power converter. The system includes a first comparator, and an off-time component. The first comparator is configured to receive a sensing signal and a first threshold signal and generate a first comparison signal based on at least information associated with the sensing signal and the first threshold signal, the power converter being associated with a switching frequency and further including a switch configured to affect the primary current. The off-time component is configured to receive the first comparison signal and generate an off-time signal based on at least information associated with the first comparison signal. The off-time component is further configured to, if the first comparison signal indicates the sensing signal to be larger than the first threshold signal in magnitude, generate the off-time signal to keep the switch to be turned off for at least a predetermined period of time.

Abstract: First FET switches control supply of electricity from an external power supply to a primary winding of a transformer. A condenser is connected, in series, to a secondary winding of the transformer. A second FET switch is connected, in parallel, to the secondary winding and the condenser. The diode is connected, in parallel, to the second FET switch. A switch control unit acquires a value obtained by measuring a current flowing through the first FET switches and the second FET switch and controls, on the basis of the measurement result of the current, conduction of the first FET switches and the second FET switch.

Abstract: Methods and systems for current sharing using interleaved LLC power converters are described herein. The method provides for current sharing between a first LLC power converter interleaved with a second LLC power converter. The method includes determining an expected output voltage for at least one of the first and second LLC power converters and measuring an output voltage of at least one of the first and second LLC power converters. The method also includes increasing a dead-time of at least one of the first and second LLC power converters when the measured output voltage exceeds the expected output voltage. Finally, the method includes interleaving the first and second LLC power converters, wherein an output current of the first LLC power converter is substantially equal to an output current of the second LLC power converter.

Abstract: A control circuit for a synchronous rectification circuit, a LLC resonant converter and a control method. The control circuit has a first comparing circuit, a second comparing circuit, a blanking circuit, a first logic circuit and a second logic circuit. The blanking circuit is configured to provide a first blanking signal and a second blanking signal to avoid one or more repeated conduction of a first synchronous rectifier and a second synchronous rectifier respectively, and the first blanking signal and the second blanking signal are logic complementary.

Abstract: A resonance type high frequency heating apparatus comprising; a direct current power supply; a series connection circuit consisting of a pair of semiconductor switching elements connected in parallel to the direct current power supply; another series connection circuit having a primary coil of a leakage transformer and a capacitor connected to both ends of one of the pair of semiconductor switching elements; and a drive means for driving each of the pair of semiconductor switching elements; wherein a variable dead time preparation circuit is provided in the drive means, and the variable dead time preparation circuit enables dead time to remain constant at below a predetermined frequency and causes the dead time to increase sharply at a point above a predetermined frequency.

Abstract: System and method are provided for regulating a power converter. The system includes a signal processing component configured to receive a first input signal and a second input signal, process information associated with the first input signal and the second input signal, and output a drive signal to a switch based on at least information associated with the first input signal and the second input signal. The first input signal is associated with at least a feedback signal related to an output voltage of the power converter. The second input signal is associated with at least a primary current flowing through a primary winding of the power converter. The signal processing component is further configured to change a peak value of the primary current within a first predetermined range, and change the switching frequency of the power converter within a second predetermined range.

Abstract: A switching power-supply device includes a COMP-voltage comparator circuit that compares a COMP-voltage obtained by performing phase compensation on the feedback signal, with a first threshold voltage which is a threshold value; and an intermittent-oscillation control circuit that, if it is detected by the COMP-voltage comparator circuit that the COMP-voltage is lower than the first threshold voltage, stops the switching operation of the switching device and performs a transition to a first intermittent oscillation operation in which the switching device performs the switching operation every predetermined first period, wherein if a predetermined delay period elapses in a state where the COMP-voltage is lower than the first threshold voltage, the intermittent-oscillation control circuit performs a transition to a second intermittent oscillation operation in which the switching device performs the switching operation every second period which is an integral multiple of the first period.

Abstract: The power supply apparatus includes a switch element for turning ON and OFF supply of electric power to a primary winding of a transformer; a determining unit connected to an auxiliary winding of the transformer, for determining an ON-time of the switch element; and a switching unit for switching the ON-time determined by the determining unit.

Abstract: A power converter reduces output ripple without using an electrolytic primary-side capacitor that can reduce product lifetime. Primary-Side Regulation (PSR) using an auxiliary winding provides a regulated secondary voltage with some low-frequency ripple on a secondary winding of a transformer. A smaller secondary capacitor that is not an electrolytic capacitor filters the output of the secondary side. A bang-bang controller controls the secondary side current to reduce current ripple despite voltage ripple. The bang-bang controller has a series resistor and inductor in series with a load such as an LED. A voltage drop across the series resistor increases when a switch turns on. This increasing voltage drop toggles the switch off once an upper limit voltage is reached. The voltage drop then decreases as inductor current is shunted by a diode, until the voltage drop reaches a lower limit voltage and the switch toggles on again.

Abstract: A power converter includes a rectifier and a power factor corrector. The rectifier is to be coupled to an alternating current power source and is configured to output a rectified signal. The power factor corrector includes a correcting circuit and a control circuit. The correcting circuit receives the rectified signal and is configured to generate an output voltage based on the rectified signal and a driving signal. The control circuit is configured to generate a first to-be-compared signal based on the rectified signal, to generate a second to-be-compared signal based on the output voltage, to compare the first and second to-be-compared signals, and to generate the driving signal based on a result of comparison performed thereby.

Abstract: Devices and systems for power electronic circuits are provided. Embodiments of the present invention enable high density inductive energy storage by using electromechanical coupling between an electrically conducting inductive element and a mechanical resonator to passively store energy via both electromagnetic and mechanical mechanisms. A microelectromechanical inductor (MEMI) is provided utilizing a magnet and a conductor. In a specific embodiment, the MEMI includes a permanent magnet on a compliant layer centrally disposed within a spiral coil. In a further embodiment, a second coil is provided near the magnet to provide a resonating transducer.

Abstract: One embodiment includes a power supply system including a transformer comprising a primary, secondary, and auxiliary winding that are magnetically coupled. The system also includes a switch stage that generates a current through the primary winding in response to activation of a switch based on a control signal that is generated based on a feedback voltage associated with the auxiliary winding. The current can be induced in the secondary winding. The system also includes an output stage coupled to the secondary winding and that generates an output voltage based on the current induced in the secondary winding. The system further includes a feedback stage coupled to the auxiliary winding and comprising a discriminator configured to determine a zero-current condition associated with the current induced in the auxiliary winding based on monitoring a change in slope of the feedback voltage and to measure the feedback voltage during the zero-current condition.

Abstract: An LLC converter having a bridge circuit coupled to an input voltage at least one pair of power switches, a resonant network, coupled to the bridge circuit and driven by power switches, an output transformer coupled to the resonant network having first and second primary side windings and a secondary side winding, a current sense transformer on the primary side in series to the resonant network and the first primary winding, an integrator circuit coupled in parallel to the second primary side winding and in parallel to the secondary side winding of the current sense transformer the transformer providing an output current of the LLC series resonant converter and a frequency adjustment controller coupled to at least one pair of power switches and the current sense transformer and the integrator circuit providing driving signals to the at least one pair power switches.

Abstract: A converter circuit includes an input filter including an input capacitor configured to filter electromagnetic interference from an input voltage. The converter circuit includes an output capacitor, a first inductor coupled to the input capacitor, a switch coupled to the first inductor and configured to control a level of current flowing in the first inductor, a coupling capacitor connected to the first inductor, and an output rectifier coupled between the coupling capacitor and the output capacitor. A damping circuit that is configured to damp a resonant frequency of the converter circuit is coupled in parallel with the coupling capacitor.

Abstract: An AC/DC converter comprising an input rectifier circuit connected in series with a primary winding (5) of an isolating transformer (6) and to a chopper switch (T1) driven by a control circuit (10) using pulse width modulation on the basis of a signal representative of a primary current, the isolating transformer having a first secondary winding (7) that is wound in the same direction as the primary winding and that is connected to an output line (8) of the converter via a diode (D4) and a filter coil (L1), and a second secondary winding (9) that is wound in the opposite direction to the primary winding and that is connected directly to the output line via a diode (D2), the output line being connected to an output capacitor (Cout).

Abstract: System and method for regulating a power converter. A system for regulating a power converter includes a controller, a first switch, and a second switch. The controller is configured to generate a first switching signal and a second switching signal. The first switch is configured to receive the first switching signal, the first switch being coupled to an auxiliary winding of the power converter further including a primary winding and a secondary winding. The second switch is configured to receive the second switching signal and coupled to the primary winding of the power converter. The controller is further configured to, change, at a first time, the second switching signal to open the second switch, maintain, from the first time to a second time, the first switching signal to keep the first switch open, and change, at the second time, the first switching signal to close the first switch.

Abstract: A three-phase resonant cyclo-converter including a closed loop control module for controlling the switching frequency of the cyclo-converter, the closed loop control module including: a voltage signal development module arranged to develop a voltage signal representative of a voltage output waveform of the cyclo-converter, a storage module arranged to accumulate voltage signal values for phase portions of the voltage output waveform, where the voltage signal values are based on a voltage error signal and accumulated historical voltage signal values for the same corresponding phase portions, and a switching frequency control module arranged to develop a switching frequency control signal to control the switching frequency of the cyclo-converter based on the accumulated voltage signal values for corresponding phase portions of the voltage output waveform, and a proportional voltage signal based on a difference between the developed voltage signal and a reference voltage signal.

Abstract: A method of driving an isolated converter includes opening a first bi-directional switch on an input side of a transformer, accepting current into a resonant capacitor connected across the first bi-directional switch to reduce voltage across the first bi-directional switch in response to said opening the first bi-directional switch, reversing current out of the resonant capacitor, and closing the first bi-directional switch as voltage across the first bi-directional switch is approximately zero volts.

Abstract: A power factor correction (PFC) power converter is disclosed that converts AC input power to DC output power. A single stage of the PFC power converter performs both the DC-DC power conversion and the power factor correction for the power converter. The disclosed PFC power converters are efficient in energy conversion and have a power factor of 0.9-1.0. Further, the disclosed PFC power converters can be implemented in both low and high power applications above 75W.

Abstract: A control device for a resonant converter is described. The converter comprises a switching circuit adapted to drive a resonant circuit that includes at least one capacitor. The converter is adapted to convert an input signal into an output signal and the switching circuit includes at least a half bridge of first and second switches, the central point of said half bridge being connected to the resonant circuit. The control device comprises a controller adapted to generate at least a control signal of the switching circuit by comparing a signal representative of the energy of the resonant circuit with at least another signal.

Abstract: A resonant power conversion apparatus and a controlling method of the resonant power conversion apparatus are provided. The resonant power conversion apparatus includes a switch-based resonant converter and a controller. The switch-based resonant converter is configured to supply power to a load. The controller is coupled to the switch-based resonant converter and the load and configured to control switching of the switch-based resonant converter to regulate power conversion of the switch-based resonant converter. The controller has a voltage control loop and a current control loop. The controller detects a driving state of the load and enables one of the voltage control loop and the current control loop according to the detection result to adjust a switching frequency of the switch-based resonant converter.

Abstract: Provided are a switch control device, a switch control method, and a power supply device. The present invention generates power voltage required to operate the switch control device by using full-wave current rectification voltage generated by rectifying an AC input and detects a zero cross-point when a full-wave rectification voltage is zero voltage by using the edge of power voltage. The present invention generates a reference signal synchronized to the full-wave rectification voltage by using the detected zero cross-point and controls a switching operation of a power switch by comparing a reference signal with current which flows on the power switch.

Abstract: A system includes a power converter configured to convert input power into output power. The power converter includes first and second converter bridges, where each converter bridge includes multiple transistors. The system also includes a zero-voltage switching (ZVS) assistance circuit having first and second inverse controlled rectifiers (ICRs). Each of the first and second ICRs is configured to provide current to the transistors in the first and second converter bridges. The system further includes a controller configured to control operation of the first and second converter bridges and the ZVS assistance circuit. The controller could include a phase-shift modulation (PSM) controller configured to control the converter bridges and a pulse width modulation (PWM) controller configured to control the ZVS assistance circuit.

Abstract: A current detecting circuit detects a resonant current in a primary side of a resonant converting circuit to generate a current detecting signal. An output detecting circuit generates a feedback signal according to the output voltage. A resonant controller generates a clock signal and adjusts an operating frequency of the clock signal in response to the feedback signal for modulating the output voltage of the resonant circuit. The resonant controller includes a resonance deviation protection unit which detects the current detecting signal according to a phase of the clock signal to determine whether the resonant circuit enters a region of zero current switching or not. When the resonant circuit enters the region of zero current switching, the resonant controller executes a corresponding protection process in response to that the resonant controller operates in a starting mode or a normal operating mode.

Abstract: This disclosure relates to a switching power supply with regulated voltage suppression to reduce transformer audio noise. The switching power supply is operable to be fed a zero crossing voltage and to generate an output voltage. The output voltage may have a voltage level set using a modulated gate signal. A circuit is provided to reduce audio noise in a switching power supply by setting a ringing suppression time of the modulated gate signal to a first time period when the zero crossing voltage is below a predetermined voltage threshold and to a second time when the zero crossing voltage is above the predetermined threshold voltage.

Abstract: A power converter comprises an input port configured to receive a source of power, an output port configured to provide output power, and a bridge circuit coupled to the input port. The bridge circuit comprises a first switch coupled in series with a second switch, and a third switch coupled in series with a fourth switch. A first clamp rectifier is coupled in series with a second clamp rectifier, and the first and second clamp rectifiers are coupled in parallel with the first and second switches. A first clamp capacitor is coupled between the first and second clamp rectifiers, with the first clamp capacitor operative to reduce power loss in the first and second clamp rectifiers. A first resonant inductor is coupled between the first and second switches. The power converter also includes a transformer operatively coupled to the bridge circuit, with the transformer comprising a primary winding and at least one secondary winding.

Abstract: A control device detects zero crossings of a current through a rectifier transistor during plural cycles; generates a turn-on signal of the transistor and inserts a turn-on delay equal to a fixed first quantity from the start time of for each cycle. The control device starts counting consecutive cycles after inserting the turn-on delay; detects whether a zero crossing of the current through the transistor after turning on said transistor has occurred; if no zero crossing is detected before counting a number N of consecutive cycles, decreases the turn-on delay by a fixed second quantity for the next cycle; if a zero crossing is detected, maintains turned on the transistor; if the turn-on delay is smaller than first quantity, increases the turn-on delay o for the next switching cycle; and if the turn-on delay is equal to the first quantity, maintains the turn-on delay for the next switching cycle.

Abstract: A control device controls a rectifier of a switching converter that is supplied with an input voltage and provides an output current. The rectifier is configured to rectify the output current of the converter and has at least one transistor. The control device, when the at least one transistor is turned off, provides a slow discharge path to ground in a normal operation condition and provides a fast discharge path to ground for discharging the control terminal of the at least one transistor in response to detecting a zero cross event of the current flowing through said at least one transistor.

Abstract: An impedance control resonant power converter (converter) operated at a fixed switching frequency includes an impedance control network (ICN) coupled between two or more inverters operated at a fixed duty ratio with a phase shift between them and one or more rectifiers. The phase shift is used to control output power or compensate for variations in input or output voltage. The converter operates at fixed frequency yet achieves simultaneous zero voltage switching (ZVS) and zero or near zero current switching (ZCS) across a wide operating range. Output power may be controlled by: (1) changing phase shift between inverters; or (2) adjusting phase shift between inverters depending upon input and/or output voltages so that an admittance presented to the inverters is conductive and then turning the converter on and off at a frequency lower than the converter switching frequency to control output power below a value set by the phase shift.

Abstract: Method and apparatus for extending a zero voltage switching (ZVS) range during power conversion. In one embodiment, the apparatus comprises a DC/DC converter, operated in a quasi-resonant mode, comprising a transformer; a primary switch, coupled to a primary winding of the transformer, for controlling current flow through the primary winding; and a component coupled to the transformer, wherein the component has a capacitance that varies with voltage across the component, and wherein during a downswing in voltage across the primary switch the component is passively tuned by a change in the voltage across the component that changes the capacitance of the component, and wherein the passive tuning of the component causes a resonant frequency of the DC/DC converter to change, and wherein the change in the resonant frequency causes the downswing to accelerate.

Abstract: Switched-mode power supply device having an input for receiving an AC voltage input signal, an output for providing a DC voltage signal and/or a direct-current signal to a downstream consumer, a transformer having a primary winding and a secondary winding, and resonant converter means assigned to the primary side of the transformer, which resonant converter means form an LLC topology with inclusion of the primary winding and can be actuated with a variable-frequency control signal on the primary side by means of a control unit, wherein the control unit, which is realized by means of an integrated and/or programmable circuit component, generates the control signal in reaction to and as a function of a zero-crossing detection signal generated from the AC voltage input signal, a current flowing in the transformer windings, in particular on the secondary side, and a constant and/or predeterminable preset signal for an output current flowing at the output, in such a way that regulating means associated with the co

Abstract: An electrical circuit for providing electrical power for use in powering electronic devices is described herein. The electrical circuit includes a power converter circuit that is electrically coupled to an electrical power source for receiving alternating current (AC) input power from the electrical source and delivering direct current (DC) output power to an electronic device. The power converter circuit includes a transformer and a switching device coupled to a primary side of the transformer for delivering power from the electrical power source to a primary side of the transformer. A controller is coupled to a voltage sensor and the switching device for receiving the sensed voltage level from the voltage sensor and transmitting a control signal to the switching device to adjust the voltage level of power being delivered to the electronic device.

Abstract: A resonant converter, a power supply and a power controlling method thereof are provided. The power supply includes a resonant converter which includes a square wave generator configured to alternately turn on and off first and second switches according to a frequency to generate a square wave, a resonant wave generator configured to generate a resonant wave corresponding to the square wave and a rectifier configured to output a voltage corresponding to the resonant wave; and a controller configured to control a frequency modulation of the resonant converter, wherein the controller includes a variable switching circuit configured to increase the frequency of the resonant converter in response to the resonant converter entering a capacitive mode.

Abstract: A LLC bidirectional resonant converter comprising: a resonant tank, a first switching circuit connected to the resonant tank via first power conduits, a second switching circuit connected to the resonant tank via second power conduits, a switching element, and at least one switchable inductive element which is arranged by the switching element to be in parallel across the second power conduits when operating in a first mode of operation and arranged by the switching element to be in parallel across the first power conduits when operating in a second mode of operation.

Abstract: The disclosed switching regulator, including a controller for a switching regulator, is adaptable to supplying, or controlling the supply of, regulated current to a load that is isolated from a source of input power by a flyback transformer, and includes: (a) detecting, after transistor SWOFF, a zero crossing ZCD corresponding to a primary side switching node voltage VSW decreasing to the input voltage Vin, which occurs after a secondary current IS is substantially zero and before the next SWON; (c) establishing a time-integral window T-I_W with a leading edge corresponding to SWOFF and a trailing edge corresponding to ZCD; and (d) modulating at least the time SWOFF relative to SWON based on the primary peak current IPP at SWOFF and the time-integral window, such that a regulated load current is supplied to the load.

Abstract: A switching power source device IS capable of guaranteeing a normal switching operation even when the input of a coil voltage used for adjusting a dead time is eliminated. The switching power source device includes a dead time adjustment circuit that generates an ON trigger signal that regulates an ON timing of one of the first and second switching elements after elapse of a predetermined dead time from an OFF timing of the other switching element and that adjusts the dead time according to a temporal change of a terminal voltage detected from an auxiliary coil of an inductor; and a disable control circuit that detects a temporal change of the coil voltage during activation and disables a function of the dead time adjustment circuit adjusting the dead time when the coil voltage does not temporally change.

Abstract: This disclosure relates to a switching power supply with regulated voltage suppression to reduce transformer audio noise. A switched mode power supply (SMPS) may supply power at different levels according to output loads. A switching frequency of the SMPS may be adjusted according to the output load. The switching may be subject to a ringing suppression time, a maximum on time, and a maximum switching period. By controlling the switching frequency subject to these quantities, the audible noise of an SMPS may be reduced or eliminated.

Abstract: Apparatus for extending a zero voltage switching (ZVS) range during DC/DC power conversion. The apparatus comprises a DC/DC converter, operated in a quasi-resonant mode, comprising (i) a transformer, (ii) a primary switch, coupled to a primary winding of the transformer, for controlling current flow through the primary winding, and (iii) a varactor, coupled to the transformer, for accelerating a downswing in a voltage across the primary switch.