Abstract: An integrated circuit for a power supply circuit that generates an output voltage from an input voltage. The power supply circuit includes a transformer, a transistor controlling an inductor current flowing through a primary coil of the transformer, a first capacitor, and a first diode charging the first capacitor. The integrated circuit is configured to control switching of the transistor. The integrated circuit includes a first terminal configured to receive a voltage across the first capacitor; a second terminal configured to receive a feedback voltage corresponding to the output voltage; a driving signal output circuit configured to output a driving signal to increase a switching period of the transistor, in response to a decrease in a load current; a driver circuit configured to drive the transistor in response to the driving signal; and a determination circuit configured to determine whether the power supply voltage drops below a first voltage.

Abstract: A resonant asymmetrical half-bridge flyback power converter includes: a first transistor and a second transistor switching a transformer coupled to a capacitor for generating an output power; a voltage divider coupled to an auxiliary winding of the transformer; a differential sensing circuit which includes a first terminal and a second terminal coupled to the voltage divider to sense an auxiliary signal generated by the auxiliary winding for generating a peak signal and a demagnetization-time signal; and a PWM control circuit configured to generate a first PWM signal and a second PWM signal in accordance with the peak signal and the demagnetization-time signal, for controlling the first transistor and the second transistor respectively; wherein a period of an enabling state of the demagnetization-time signal is correlated to the output power level; wherein the peak signal is related to a quasi-resonance of the transformer after the transformer is demagnetized.

Abstract: A dual mode charge control method includes steps of: detecting an input voltage of the resonance tank, a resonance current of the resonance tank, an output current of the load, and an output voltage of the load; performing a single-band charge control when determining a light-load condition or a no-load condition of the load according to the output current; compensating the output voltage to generate an upper threshold voltage in the single-band charge control, and acquiring a resonance voltage by calculating the resonance current by a resettable integrator; comparing the resonance voltage and the upper threshold voltage to generate a first control signal; generating a second control signal complementary to the first control signal by a pulse-width modulation duplicator; providing the first control signal and the second control signal to respectively control a first power switch and a second power switch of the resonance circuit.

Abstract: A charging device, comprising a first power converter configured to provide a first output current, a second power converter configured to provide a second output current, a switch coupled to an output of the first power converter and an output of the second power converter, a first socket coupled to the output of the first power converter, a second socket coupled to the output of the second power converter, and a power delivery (PD) controller configured to control a turn ON of the switch in response to a coupling of the first socket to a first powered device and an absence of coupling of the second socket to a second powered device.

Abstract: A PFC power converter includes a power switch and an inductive device. A compensation signal is provided in response to an output voltage of the PFC power converter. An adapted compensation signal is provided in response to an ON time of the power switch and the compensation signal, to make the adapted compensation signal, the ON time, and the adapted compensation signal fit a predetermined correlation. The ON time of the power switch is determined in response to the adapted compensation signal. The PFC power converter is capable of achieving high PF when operating in discontinuous conduction mode.

Abstract: A flyback converter with improved over-voltage protection (OVP) functionality, which includes a primary winding arranged to receive an input voltage, a secondary winding coupled to the primary winding and connected to a rectifier circuit to generate DC output voltage, a primary side regulating controller, an auxiliary winding arranged to provide electric power to the primary side regulating controller, an external detection circuit connected between the auxiliary winding and the primary side regulating controller, an internal detection circuit arranged inside the primary side regulating controller and coupled to the external detection circuit by detecting the current value flowing through the external detection circuit and comparing it with a predetermined current value of the internal detection circuit to enable or disable an OVP circuit to protect the primary side regulating controller, and a switching device arranged to receive on/off signals generated for regulating current flowing through the primary win

Abstract: A heating device includes a heat generating element, a switching element, a capacitor, a connecting portion, and a controller. When the connecting means is changed in state from an on state to an off state, the controller causes the capacitor to discharge an electric charge of the capacitor by bringing the switching element into a conduction state for a predetermined time after the connecting means is changed in state to the off state.

Abstract: A system for modular dynamically adjustable capacity storage for a vehicle is provided. The system includes a battery pack including a plurality of battery cells, a negative terminal including a chassis ground connection, and a plurality of positive battery pack terminals. The negative terminal and the plurality of positive battery pack terminals are useful for connecting at least one electrical circuit through the battery pack. The system further includes a battery cell switching system, including a plurality of solid-state switches connected to each of the battery cells. The plurality of solid-state switches is operable to selectively connect a portion of the battery cells in parallel, selectively connect the portion of the battery cells in series, and selectively connect one of the plurality of battery cells to one of the plurality of positive battery pack terminals.

Abstract: A method for controlling a switching mode power supply is disclosed. An auxiliary winding feedback voltage of the switching mode power supply is sampled and held to obtain an auxiliary winding sample hold voltage. The auxiliary winding feedback voltage is sampled and held at an inflection point time to obtain an auxiliary winding inflection point voltage when the switching mode power supply operates in DCM or CRM. A secondary rectifier forward voltage signal is generated based on the auxiliary winding sample hold voltage and the auxiliary winding inflection point voltage before the switching mode power supply operates in CCM. A correction voltage is provided based on the secondary rectifier forward voltage signal when the switching power supply operates in CCM. An error amplifier signal is generated based on the correction voltage. The output power of the switching mode power supply is adjusted based on the error amplifier signal.

Abstract: An active clamp flyback (ACF) converter can be used to convert AC voltages to DC voltages and offers the ability to reuse leakage energy and a negative magnetizing current to achieve zero-volt-switching. The leakage energy can vary with system design and therefore may be difficult to control, but the negative magnetizing current can be controlled by adjusting a switching frequency of the ACF converter. The adjustment can be determined by comparing the negative magnetizing current to a threshold. Using a fixed threshold may not be optimal because variations in system operating conditions, such as load current, line voltage, and output voltage, can affect the amount of negative magnetizing current required for zero-volt-switching (i.e., can affect the threshold). Additionally, a range of possible switch technologies can affect the threshold. The present disclosure describes an adaptable threshold for a variable frequency ACF converter that allows for efficient switching.

Abstract: A power delivery system includes a PD source device and a PD sink device. The PD source device is configured to detect its connection status with the PD sink device and determine whether its power supply is high-voltage operation. When determining that the PD source device is supplying high-voltage power and detecting that the PD source device is detached from the PD sink device, the PD source device is configured to provide an oscillating rapid discharging path for its output capacitor, thereby rapidly reducing its output voltage and suppressing electrical arc.

Abstract: A power conversion device for controlling a DC voltage of a DC link may comprise a first diode, a second diode, a first switching element, a second switching element, a third switching element, and a fourth switching element, wherein: a cathode terminal of the first diode is connected to a positive terminal of the DC link; an anode terminal of the first diode is connected to one end of the first switching element and one end of the third switching element; the other end of the first switching element is connected to an alternating current terminal and one end of the second switching element; the other end of the second switching element is connected to one end of the second diode and one end of the fourth switching element; the other end of the second diode is connected to a negative terminal of the DC link.

Abstract: A method of optimizing the efficiency of an AC-DC converter, wherein the energy extraction time from the AC line is increased and as result the size of the bulk capacitor can be decreased and in applications wherein the size of the bulk capacitor is maintained constant the ripple across the bulk capacitor is decreased. The methods presented also increase the power factor in AC-DC converters. Extending the energy extraction from the AC line also lowers the RMS current through the input bridge and the input bulk capacitor. The reduction of the ripple across the bulk capacitor also increases the efficiency of the DC-DC converter, increasing in this way the overall efficiency of the AC-DC converter.

Abstract: This application provides a battery protection circuit, a battery protection board, a battery, and a terminal device. The battery protection circuit includes: a first detection unit; a second detection unit; and a current detection element, a first switch unit, and a second switch unit that are configured to connect to an electrochemical cell in series, to form a charging loop or a discharging loop. The first detection unit corresponds to the first switch unit, and the second detection unit corresponds to the second switch unit. Each detection unit controls, based on a detected voltage at two ends of the same current detection element, a corresponding switch unit to be closed or opened, so as to control the loop to be closed or opened.

Abstract: A system that includes a first transistor to provide a drive voltage to a coupled inductor is disclosed. The coupled inductor can receive the drive voltage and generate a voltage output. A second transistor can receive a switching voltage generated from the voltage output to isolate a load positionable downhole in a wellbore from a voltage source.

Abstract: A light-emitting diode (LED) drive method, an LED drive circuit, and an LED lighting device are provided. The method includes: setting preset values of a maximum on-time parameter and a current limit parameter, where the preset values are in at least two sets; selecting a set of the preset values of the maximum on-time parameter and the current limit parameter after a value of a voltage signal on a direct current (DC) bus is detected; controlling a drive current flowing through an LED load based on a selected maximum on-time parameter and a selected current limit parameter. The maximum on-time parameter and the current limit parameter of the system can be adaptively adjusted according to an input voltage, so that the system can have a preferred dimming schedule and dimming depth while realizing a constant current in a wider input voltage range.

Abstract: A charger includes a rectifier including two input terminals for connection to an AC power supply, a cathode terminal and an anode terminal, a DC/DC converter including a first terminal be connected to the cathode terminal, a second terminal to be connected to the anode terminal, and two output terminals for connection to a battery, a power pulsation absorbing circuit including a first diode, a second diode, a third diode, an inductor, a capacitor, a first switch and a second switch, and a control section configured to control a switch of the DC/DC converter, the first switch and the second switch, wherein the control section is configured to control the DC/DC converter, the first switch and the second switch in such a way that a sum of a power outputted from the AC power supply and a power outputted from the capacitor is constant.

Abstract: A switching-type regulation driver includes a transformer, a controller, a synchronous rectifier and a drive control module. The drive control module is connected to the synchronous rectifier and the non-dotted terminal of the secondary winding respectively, and is used to detect a target parameter of a voltage across both power ends of the synchronous rectifier when the synchronous rectifier disconnects the conductive path between the non-dotted terminal of the secondary winding and the reference ground. When it is detected that the target parameter of the voltage across both power ends of the synchronous rectifier meets a preset condition, the controller controls a switching action of the first transistor so that the primary winding transmits power to the secondary winding. According to the present disclosure, the pre-stage chip may be matched with to realize a function of dynamic acceleration, and the dependence on the output pin may be reduced.

Abstract: A buffer circuit coupled in parallel to a rectifier circuit in a secondary side of a flyback converter, the buffer circuit including: a capacitive element configured to be charged by an output capacitor when a primary power switch in the flyback converter is turned on; and the capacitive element being configured to be discharged through a secondary winding of a transformer when the primary power switch is turned off, in order to reduce energy stored in a primary leakage inductor in a primary side of the flyback converter, whereby a spike voltage generated in a secondary leakage inductor in the secondary side is reduced, and efficiency of the flyback converter is improved.

Abstract: A control circuit, a chip and a control method are disclosed. The control circuit includes: an adjustment signal generation unit configured to detect an electrical signal reflecting a power supplied to a load under control of a current value of a reference signal, generate a feedback signal and output an adjustment signal based on both the feedback signal and the reference signal; and a control unit coupled to the adjustment signal generation unit and configured to control the switching circuit on and off based on the adjustment signal. With the generated adjustment signal that reflects a change in an adjustment metric indicated in the reference signal, the control circuit and the driving system can be adapted in real time to the specifications of any AC power standard. Moreover, much more granular adjustments can be made in the power supplied to the load.

Abstract: A control method of a flyback power converter includes a voltage detection pin detecting conduction time of a power switch of a primary side of the flyback power converter, a feedback pin detecting conduction time of a synchronous switch of a secondary side of the flyback power converter, the feedback pin detecting a number of inductor capacitor resonant valleys when the flyback power converter operates in a discontinuous conduction mode, and a high voltage detection pin detecting an input voltage inputted in the flyback power converter; and a controller applied to the flyback power converter making the flyback power converter operate in a quasi-resonant mode when the number of the inductor capacitor resonant valleys is greater than a predetermined number, an operational frequency of the flyback power converter is less than a predetermined frequency, and the input voltage is less than a predetermined voltage.

Abstract: The subject application provides a zero-voltage switching flyback converter comprising: a transformer having a primary winding and a secondary winding; a primary switch and a secondary switch for conducting the currents flowing in the primary winding and secondary winding respectively. A timing control method for operating the flyback converter are provided to accomplish zero-voltage switch by turning on the secondary switch twice within one switching power cycle.

Abstract: The power supply apparatus alternately repeats a control between a first control of varying a frequency of switching operation within a predetermined range and for a predetermined cycle according to a frequency determined based on a feedback voltage, and a second control of varying the frequency within a range narrower than the predetermined range or a third control of controlling the frequency to be a constant frequency.

Abstract: A high voltage pulse generator is disclosed. The high voltage pulse generator comprises a pulse generating transformer having a primary coil with a first side and a second side, and a secondary coil with a first side and a second side. A direct current (DC) voltage source connection is at the first side of the primary coil. A first high frequency power driver transistor is coupled between the second side of the primary coil and a ground connection. The first high frequency power driver transistor is configured to operate in an on-mode for a selected time period to charge the primary coil for the selected time period based on a switching frequency of the first high frequency power driver transistor, and switch the first high frequency power driver transistor to an off-mode at the switching frequency to release the charge from the primary coil to the secondary coil.

Abstract: A power controller is in use of a power converter whose output voltage can be regulated at a first nominal output voltage or a second nominal output voltage less than the first nominal output voltage. An ON-time controller controls an ON time of a driving signal provided to a power switch according to a compensation signal. A frequency controller controls, based on the compensation signal and a feedback signal, a switching frequency of the driving signal. If the compensation signal has an input waveform and when the output voltage is regulated at the first or second nominal output voltage, the frequency controller provides first or second settling time to stabilize the switching frequency, respectively. The second settling time is longer than the first settling time.

Abstract: A topical nerve activation patch includes a flexible substrate, a dermis conforming bottom surface of the substrate comprising adhesive and adapted to contact a dermis of a user, a flexible top outer surface of the substrate, a plurality of electrodes positioned on the patch proximal to the bottom surface and located beneath the top outer surface and coupled to the flexible substrate, a power source, and electronic circuitry that generates an output voltage applied to the electrodes. The electronic circuitry includes a controller, a voltage monitoring circuit coupled to the controller, a current monitoring circuit coupled to the controller, a switch coupled to the controller and a two stage boosted voltage circuit coupled to the switch and the power source that is configured to increase a switch voltage level to approximately a half value of a final output voltage before increasing to the final output voltage.

Abstract: A method and apparatus are described for controlling the gain of a phase loop of an interleaved boost converter using cycle signals. In an embodiment, a phase compensator compares a duration of the power phase of a converter to a cycle duration for the converter to generate a phase compensation. A phase adjustment module receives phase feedback signals of the first and second converters, measures the phase difference, receives the phase compensation, and generates a phase control output in response. A cycle controller receives the phase control output and generates first and second drive signals to control switching of first and second gates of the respective converters, wherein times of the first and second drive signals are adjusted using the phase control output.

Abstract: A power converter controller includes a fractional valley controller configured to determine a target number of valleys of a resonant waveform at a drain node of a main switch, the target number of valleys corresponding to a desired off-time of the main switch, the fractional valley controller modulating an off-time of the main switch between two or more modulated off-times. The target number of valleys corresponds to a non-integer number of valleys of the resonant waveform at the drain node of the main switch. Each of the modulated off-times of the main switch corresponds to an integer number of valleys, and the two or more modulated off-times of the main switch has an average value that corresponds to the desired off-time.

Abstract: When a constant on-time flyback converter is in the switch-on stage, the gate voltage of the switch and the input voltage of the flyback converter adopt the primary side of the transformer to control. The gate voltage is controlled by the second control signal generated by the controller. The flyback converter is then turn off to enter the switch off stage. When the flyback converter is in the switch off stage, the secondary side controller on the secondary side of the transformer, based on the output voltage and output current of the secondary side, sends a first control signal to the primary side controller to control the main switch to turn on. Thus, the flyback converter enters the switch-on stage. Therefore, the calculation complexity is reduced, and there is no need to set a blanking time, such that the flyback converter can be used in high switching frequency applications.

Abstract: System and method for protecting a power converter. The system includes a first comparator configured to receive a first threshold signal and a first signal and to generate a first comparison signal. The first signal is associated with an input current for a power converter. Additionally, the system includes a second comparator configured to receive a second threshold signal and the first signal and to generate a second comparison signal. The second threshold signal is different from the first threshold signal in magnitude. Moreover, the system includes a first detection component configured to receive at least the second comparison signal, detect the second comparison signal only if one or more predetermined conditions are satisfied, and generate a first detection signal based on at least information associated with the detected second comparison signal.

Abstract: A power supply system according to the present embodiment includes a plurality of first power converters configured to supply power according to dispatching characteristics of power to be supplied to a load, and a plurality of control devices each configured to associate a change ratio of active power to an output frequency of each of the first power converters with the dispatching characteristics and control each of the first power converters based on the change ratio.

Abstract: Methods, apparatus, systems and articles of manufacture are disclosed for preventing undesired triggering of short circuit or over current protection. An example apparatus includes an output terminal; a voltage detection device coupled to a voltage detection input terminal and the output terminal and including a voltage detection output coupled to a logic gate first input terminal; a pulse extender coupled between a logic gate output and a selecting node; a multiplexer coupled to the selecting node and configured to be coupled to a first protection circuit, a second protection circuit, and a driver; and a switch coupled between an input terminal and the output terminal and including a switch gate terminal coupled to the driver.

Abstract: A method of controlling an isolated switching converter having an output voltage that is adjustable, can include: sampling an output voltage of the isolated switching converter; setting an overvoltage protection threshold corresponding to the output voltage of the isolated switching converter when the isolated switching converter enters a protection mode; and triggering the overvoltage protection by comparing an output voltage feedback signal representing the output voltage against the overvoltage protection threshold.

Abstract: A differential mode electromagnetic noise injection network includes an injection piece and a differential mode loop. The injection piece includes a semiconductor transistor or a winding differential mode inductor. The injection piece is at least provided with a first injection end, a second injection end, and a differential mode electromagnetic noise component input end. The differential mode electromagnetic noise component input end is configured to input a differential mode electromagnetic noise component. The first injection end and the second injection end are connected to any two points that are connected in series in the differential mode loop in a one-to-one correspondence, and are configured to inject the differential mode electromagnetic noise component. An active electromagnetic interference filter including the differential mode electromagnetic noise injection network mentioned above is provided.

Abstract: An apparatus and a method for controlling a voltage conversion mode in an electronic device are provided. The electronic device includes a power management module, a communication processor, and at least one processor operably connected to the communication processor, wherein the at least one processor identifies a modulation order used for communication with an external device, in a case that communication with the external device is performed using a wireless resource, and configures, based on the modulation order, a voltage conversion mode of the power management module that supplies power to the communication processor to a pulse frequency modulation (PFM) mode or a pulse width modulation (PWM) mode.

Abstract: A regulated power supply includes a capacitively isolated feedback circuit and a pulse width modulator (PWM) operable to produce a plurality of pulses at an output and receive a sampled voltage at a feedback input thereof. The capacitively isolated feedback circuit includes a capacitively isolated gate drive circuit directly coupled to the PWM output and configured to produce a plurality of isolated pulses from the plurality of pulses received from the PWM output. The capacitively isolated feedback circuit also includes a forward converter feedback circuit, which includes a switching transistor directly coupled to the capacitively isolated gate drive circuit for receiving the plurality of isolated pulses at a gate of the switching transistor and a feedback transformer directly coupled to the PWM for providing the sampled voltage at the feedback input. The plurality of isolated pulses causes the feedback transformer to sample a load voltage as the sampled voltage.

Abstract: An AC-DC converter with synchronous rectifier (SR) architecture and method for operating the same are described. Generally, a secondary side IC controller of the AC-DC converter includes a SR-SNS pin coupled to a peak-detector block, a zero-crossing block, and a calibration block. The calibration block is configured to: measure a loop turn-around delay (Tloop), a time (Tpkpk) between two successive peak voltages detected on the SR-SNS pin, and a time (Tzpk) from when the voltage sensed on the SR-SNS pin crosses zero voltage to when a peak voltage is detected on the SR-SNS pin; and set timing for a signal to turn on a power switch in a primary side of the AC-DC converter based at least on Tloop, Tpkpk, and Tzpk.

Abstract: An active clamping flyback circuit and a control method are disclosed, comprising a flyback circuit, a clamping circuit and a clamping control circuit. The active clamping flyback circuit comprises a transformer, a main transistor, and a freewheeling diode or a synchronous rectifier, an output feedback circuit is coupling to an auxiliary winding of the transformer and outputs a feedback voltage through a divided voltage The clamping circuit comprises a first capacitor and a first transistor coupling in series, In a discontinuous conduction mode, the clamping control circuit starts timing from a turn-off time of the first transistor, and ends timing until the feedback voltage is reduced to zero voltage, to obtain a first time, The clamping control circuit adjusts a turn-off moment of next switching cycle of the first transistor so that the first time of the next switching cycle is close to a first threshold.

Abstract: A control apparatus for an electro-optic element comprises a first voltage converter in connection with a power supply. The first voltage converter is configured to receive a supply voltage from the power supply and output a first voltage. A first storage capacitor is in connection with the first voltage converter and configured to store first energy at the first voltage. A second storage capacitor is configured to store second energy at a second voltage, wherein the second energy is supplied by the power supply. A driving circuit in conductive connection with the second storage capacitor and configured to supply a driving voltage to the electro-optic element. In response to a failure of the power supply, the first storage capacitor is configured to supply the first energy to a controller and the second storage capacitor is configured to supply the second energy to the driving circuit.

Abstract: An AC-DC converter with synchronous rectifier (SR) architecture and method for operating the same are described. Generally, a secondary side IC controller of the AC-DC converter includes a SR-SNS pin coupled to a peak-detector block, a zero-crossing block, and a calibration block. The calibration block is configured to: measure a loop turn-around delay (Tloop), a time (Tpkpk) between two successive peak voltages detected on the SR-SNS pin, and a time (Tzpk) from when the voltage sensed on the SR-SNS pin crosses zero voltage to when a peak voltage is detected on the SR-SNS pin; and set timing for a signal to turn on a power switch in a primary side of the AC-DC converter based at least on Tloop, Tpkpk, and Tzpk.

Abstract: In an AC-DC converter having a primary side control circuit, auxiliary power for the control circuit is derived from the converter secondary side through an isolated DC-DC converter. The circuits and methods solve the problem of supplying primary side auxiliary power during light load or no load operation of the AC-DC power converter. Since the output voltage of the AC-DC converter is normally regulated at a fixed level, the auxiliary voltage that is generated by the isolated DC converter is regulated. In some cases the isolated DC-DC converter may not need to be regulated, which simplifies the design and reduces overall cost.

Abstract: A planar transformer includes a primary winding including a first primary winding layer, a secondary winding including a first secondary winding layer, where an Ns1th turn of coil to an (Ns1+B1?1)th turn of coil in the secondary winding are disposed at the first secondary winding layer, and a charge balance winding including a first charge balance winding layer, where the first charge balance winding layer is disposed between the first primary winding layer and the first secondary winding layer, and is adjacent to the first primary winding layer and the first secondary winding layer. N1 turns of coils are disposed at the first charge balance winding layer, where N1 is greater than or equal to Nb1.

Abstract: Embodiments herein provide a device for calibrating a voltage driven by a PWM signal for a circuit board. The device includes a controller configured to generate the PWM signal according to a PWM duty cycle value, and a voltage regulator configured to generate an output voltage according to the PWM signal. The controller is further configured to calibrate a relationship between the PWM duty cycle value and the output voltage based on a plurality of configured PWM duty cycle values and a plurality of corresponding voltages measured from the voltage regulator, and drive the circuit board by configuring the PWM duty cycle value based on the calibrated relationship.

Abstract: The disclosure provides a multi-phase converter. The multi-phase converter includes a controller and one or more switches. The one or more switches are coupled to the controller, and configured to receive an input voltage. A switch of the one or more switches is activated by the controller in a predefined phase of N phases in the multi-phase converter, where N is a positive integer. A processing unit is coupled to the controller and estimates a number of phases to be activated based on a load current. The processing unit also stores a threshold current limit corresponding to each phase of the N phases based on the input voltage and a switching frequency.

Abstract: A control circuit is configured to control a power factor correction (PFC) pre-regulator including a power switch and being configured to operate in a transition mode of operation and a valley-skipping mode of operation. The control circuit generates a drive signal to control a switching of the power switch based on a current threshold. A current threshold generator in the control circuit is configured to modulate the current threshold as a function of a number of valleys skipped in the valley-skipping mode of operation.

Abstract: Primary-side windings of the transformers (T1,T2,T3) are connected in parallel to each other. A switch (SW) turns on/off primary side currents of the transformers (T1,T2,T3). Each transformer (T1,T2,T3) includes a plurality of secondary-side windings.

Abstract: A power conversion apparatus including a transformer, a power switch, a pulse width modulation (PWM) signal generator, an energy storage element, and a power circuit is provided. A primary winding of the transformer receives an input voltage from an external power source. An auxiliary winding of the transformer provides an auxiliary voltage. The power switch is coupled to the primary winding. The PWM signal generator generates a PWM signal to control on and off the power switch. The energy storage element is coupled to a power terminal of the PWM signal generator. The power circuit supplies power to the PWM signal generator and charges the energy storage element according to the auxiliary voltage. When a voltage of the energy storage element is greater than or equal to a threshold voltage, the power circuit stores backup power according to the auxiliary voltage.

Abstract: A transformer and an LLC resonant converter are provided. The transformer includes first and second cores configured to include a pair of outer foots and a middle foot positioned between the outer foots, and to induce a magnetic field formation; first and second inductor winding parts configured to include a conductor surrounding a circumference of each of the pair of outer foots of the first core, and to be connected in series with each other; and first and second transformer winding parts configured to include a conductor surrounding a circumference of each of the pair of outer foots of the second core, wherein the pair of outer foots of the first core face the pair of outer foots of the second core, the middle foot of the first core faces the middle foot of the second core, and the first core and the second core are disposed to be spaced apart from each other.

Abstract: The disclosure relates to a control circuit, a control method and a flyback converter of primary-side feedback control including the control circuit. When an input voltage is greater than a predetermined threshold, a peak value of an input current of the flyback converter is controlled to vary with the input voltage by the switching control signal. When the input voltage is less than the predetermined threshold, the peak value of the input current is controlled to be increased by the switching control signal to make demagnetization time of a secondary winding of the flyback converter be greater than a minimum time. Thus, the peak value of the primary-side current may not become too small because of a decreased input voltage, further avoiding occurrence of an error sampling after a blanking time due to excessive variations in demagnetization time.

Abstract: The present invention provides an AC/DC converter comprises an input for receiving a rectified AC input signal (Vin), an output for providing a controlled output signal (Vout) to a load (7), a switched mode power converter for transforming the AC input signal (Vin) into the controlled output signal (Vout), wherein the switched mode power converter has an input for receiving a start-up voltage (Vstart) for changing a stand-by mode of the switched mode power converter into an operating mode of the switched mode power converter, a control circuit (5) for receiving a control signal (Vctl), a kick-start power supply (6) for receiving a switch-on signal (Von) to supply the start-up voltage (Vstart) being larger than a power supply voltage (Vsup), an auxiliary power supply (4) for supplying the power supply voltage (Vsup) to the control circuit (5) and the kick-start power supply (6), wherein the control circuit (5) is arranged for activating the switch-on signal (Von) to activate the kick-start power supply (6) for