Abstract: The present application provides a synchronous rectification circuit, which adopts a multiplexer that selectively inputs a first reference signal or a second reference signal to a comparator by coupling the first and second reference signal. A comparing signal is generated to a switch element by comparing a switch input signal. Hereby, the switch element is under control for synchronous rectification.

Abstract: A power supply circuit includes a transformer having a primary winding and secondary windings, a first power conversion circuit configured to convert a DC voltage into an AC voltage and output the AC voltage to the primary winding, a rectifying and smoothing circuit that is connected to the secondary winding and is configured to rectify and smooth an alternating current output from the secondary winding, and a second power conversion circuit configured to boost a direct current output from the rectifying and smoothing circuit and supply to a load a DC voltage lower than a rated voltage of the load set in advance.

Abstract: A frequency regulating circuit for a switching circuit, a frequency regulating method, and the switching circuit are provided. The frequency regulating circuit includes a charging current generating module configured to receive a first signal characterizing an output power and a second signal characterizing an input voltage to generate a charging current and a signal generating module configured to output a third signal according to the charging current. The third signal is used to adjust the maximum operating frequency of the switching circuit so that the maximum operating frequency decreases with the increase of the input voltage. Therefore, the frequency regulating circuit increases the maximum operating frequency of the switching circuit under the condition of low voltage input, which decreases the maximum operating frequency of the switching circuit under the condition of high voltage input to reduce the switching loss of the switching circuit with wide input voltage and improve efficiency.

Abstract: A conversion control circuit, configured to control a switching power converter, includes a trigger signal generation circuit, an on-time control circuit, and a logic driver circuit. The trigger signal generation circuit is configured to generate a turn-on trigger signal. The on-time control circuit is configured to generate a turn-off trigger signal to determine the on-time and/or the off-time of a pulse width modulation (PWM) signal, and adjusts the on-time and/or the off-time according to the input voltage and the output voltage, such that the switching frequency of the switching power converter is adaptively adjusted according to a ratio between the output voltage and the input voltage. The logic driver circuit is configured to generate the PWM signal according to the turn-on trigger signal and the turn-off trigger signal, wherein the turn-on trigger signal enables the PWM signal, and the turn-off trigger signal disables the PWM signal.

Abstract: The present disclosure relates to a flyback converter and a power supply system. The flyback converter comprises: a transformer; a first switching transistor and a second switching transistor; a first inductor and a first capacitor; and a control circuit. The control circuit includes an under voltage protection module configured to determine an under voltage protection threshold proportional to an output voltage of the flyback converter and to trigger an under voltage protection action of the flyback converter in a case that an input voltage of the flyback converter is less than the under voltage protection threshold. By setting an adaptive under voltage protection threshold, a system-restart phenomenon of the flyback converter after an input power failure or a shutdown may be avoided, and a PFC circuit may be turned off to optimize the standby power consumption and the low load efficiency in fast charging applications using an flyback topology.

Abstract: An energy-recycling device and a DC voltage-boosting device thereof is disclosed. The DC voltage-boosting device includes a first phase controller, an interleaved voltage booster, a second phase controller, and a phase-shift voltage converter. The first phase controller generates a first PWM signal and a second PWM signal. The interleaved voltage booster receives an input DC voltage, the first PWM signal and the second PWM signal and increases the input DC voltage to a supplying DC voltage. The second phase controller receives the supplying DC voltage and a setting voltage, thereby generating third PWM signals. The phase-shift voltage converter receives the third PWM signals and the supplying DC voltage and converts the supplying DC voltage into a stable DC voltage.

Abstract: An isolation system and isolation device are disclosed. An illustrative isolation device is disclosed to include a transmitter circuit to generate a first current in accordance with a first signal, a first elongated conducting element to generate a magnetic field when the first current flows through the first elongated conducting element, a second elongated conducting element adjacent to the first elongated conducting element so as to receive the magnetic field. The second elongated conducting element is configured to generate an induced current when the magnetic field is received. The receiver circuit is configured to receive the induced current as an input, and configured to generate a reproduced first signal as an output of the receiver circuit.

Abstract: A controller of a power converter including a first power stage and a second power stage receives an indication of an output voltage of the power converter, where the indication is measured at the primary side of the power converter. Based on the indication, a control related to an intermediate voltage of the power converter is performed.

Abstract: A control method of a zero-voltage switching converter with quasi-resonant control, the converter has a first switch and second switch respectively coupled to a primary winding and an auxiliary winding. The control method is: generating a hysteresis feedback signal based on an output feedback signal indicative of an output signal of the converter; comparing the hysteresis feedback signal with a ramp signal and generating a first comparison signal; comparing the output feedback signal with the ramp signal and generating a second comparison signal; generating a target locked valley number based on a valley pulse signal indicative of valleys of a voltage drop across the second switch, the first and second comparison signals; generating a turning on control signal corresponding to the target locked valley number for the second switch; and providing a control signal to turn on the first switch after turning off the second switch.

Abstract: A power supply apparatus including a switching element configured to supply or cut off electric power to a primary coil of a transformer by a switching operation, and a control unit configured to control the switching operation. The control unit is configured to perform intermittent control of repeating a switching period for performing the switching operation and a stop period for stopping the switching operation. In the switching period, when the control unit performs the switching operation a predetermined number of times, the switching period is transitioned to the stop period. In the stop period, when the control unit determines that a voltage output from a secondary coil of the transformer falls below a target voltage, the stop period is transitioned to the switching period. The control unit is configured to change the switching operation based on a length of the stop period.

Abstract: A motor drive system includes an electric motor, a drive circuit and a control unit. The drive circuit provides a driving current to the electric motor. A current command generator of the control unit generates a current command according to a torque command and a motor operating information. The driving current is converted into a d-axis current and/or a q-axis current by the control unit. Consequently, the driving current is close to the d-axis current command and/or the q-axis current command corresponding to the current command. If a value of the torque command is positive, the current command generator generates the corresponding current command according to a MTPA lookup table. If the value of the torque command is negative, the current command generator generates the corresponding current command according to a zero recycle lookup table.

Abstract: Apparatuses, systems, and techniques to optimize processor performance. In at least one embodiment, a method increases an operation voltage of one or more processors, based at least in part, on one or more error rates of the one or more processors.

Abstract: A power supply apparatus includes a transformer including a primary coil, a secondary coil, and an auxiliary coil; a switching element connected in series to the primary coil; a first rectifying/smoothing circuit including a first diode and a first capacitor and configured to rectify and smooth a voltage induced in the auxiliary coil; a second rectifying/smoothing circuit including a second diode and a second capacitor, connected in parallel with the first rectifying/smoothing circuit, and configured to rectify and smooth the voltage induced in the auxiliary coil; and a controller configured to control the switching element. The controller is configured to detect the voltage induced in the auxiliary coil based on an output voltage of the first rectifying/smoothing circuit. A responsiveness of the second diode is better than a responsiveness of the first diode.

Abstract: A non-isolated power supply. A positive power and a negative power are respectively formed by charging a +VCC1 energy storage filter and a ?VCC2 energy storage filter connected in series and discharging the +VCC1 energy storage filter 102 and the ?VCC2 energy storage filter. The output positive and negative power may be differently combined by changing the capacities of the +VCC1 energy storage filter and the ?VCC2 energy storage filter and may be equal or unequal.

Abstract: Systems, methods and apparatus for wireless charging are disclosed. A charging device has a plurality of charging cells provided on a charging surface, a charging circuit and a controller. The controller may be configured detect the presence of a foreign object in proximity to at least one charging coil of a plurality of charging coils in the charging device that is selected for supplying charging energy to a receiving device. Additionally, the controller may be configured to determine whether one or more other charging coils is capable of supplying charging energy to the receiving device, and determine, for each of the one or more other charging coils, whether the foreign object is in proximity thereto. Further, the controller may be configured to select at least one of the one or more other charging coils not in proximity to the foreign object for supplying charging energy to the receiving device.

Abstract: Systems and methods of this disclosure use low voltage energy storage devices to supply power at a medium voltage from an uninterruptible power supply (UPS) to a data center load. The UPS includes a low voltage energy storage device (ultracapacitor/battery), a high frequency (HF) bidirectional DC-DC converter, and a multi-level (ML) inverter. The HF DC-DC converter uses a plurality of HF planar transformers, multiple H-bridge circuits, and gate drivers for driving IGBT devices to generate a medium DC voltage from the ultracapacitor/battery energy storage. The gate drivers are controlled by a zero voltage switching (ZVS) controller, which introduces a phase shift between the voltage on the primary and secondary sides of the transformers.

Abstract: A control method in use of a flyback power converter is disclosed to provide an operation power source supplying power to a power controller controlling a main power switch. The flyback power converter has a transformer with a primary winding and an auxiliary winding. The main power switch and the primary winding are connected in series. A chopper switch and a buffer inductor are connected in series between the auxiliary winding and the power controller. The power controller turns ON the main power switch for an ON time to energize the transformer, and turns ON the chopper switch for at least a time period during the ON time, so that during the time period the buffer inductor conducts an induced current flowing from the auxiliary winding and through the chopper switch, to build up the operation power source.

Abstract: A method of operating an electronic converter is provided in which a switching activity of a switching stage of the electronic converter is active or inactive based on a control signal, and the method includes operating the electronic converter, alternatively, in a first or a second mode. In the first mode, the status signal is initially asserted and is de-asserted in response to an amplitude of the input sensing signal failing to reach a first reference threshold value. In the second mode, the status signal is initially de-asserted and an auxiliary power supply signal is periodically varied with a variation period. After a time interval equal to the variation period, a comparison signal is asserted in response to an amplitude of the sensed signal reaching a second reference threshold value. The status signal is asserted based on conditions of the comparison signal and the periodically varying auxiliary power supply signal.

Abstract: A power distribution system includes a plurality of power distribution modules connected to at least one power supply and configured to receive power therefrom. A power distribution bus connects the power distribution modules of the plurality of power distribution modules in parallel. The plurality of power distribution modules executes a distributed system policy management protocol over the power distribution bus to control a supply of available power from the at least one power supply to loads connected to USB charging ports of the power distribution modules.

Abstract: A flyback converter control architecture is provided in which primary-only feedback techniques are used to ensure smooth startup and detection of fault conditions. During steady-state operation, secondary-side regulation is employed. In addition, current limits are monitored during steady-state operation using primary-only feedback techniques to obviate the need for a secondary-side current sense resistor.

Abstract: A power provider includes: first, second, and third inductors; a first transistor connected to the second inductor; a second transistor connected to the third inductor; and a power integrated chip (IC) including input terminals connected to the first, second, and third inductors, and an output terminal connected to a power line. The power provider may supply the power voltage using the first inductor and the power IC when power current is less than a first reference value, supply the power voltage using the second inductor, the first transistor, and the power IC when the power current is greater than the first reference value and less than a second reference value, and supply the power voltage using the second and third inductors, the first and second transistors, and the power IC when the power current is greater than the second reference value.

Abstract: A resonant power conversion device includes: a main circuit provided with a semiconductor switch, a capacitor and an inductor connected in series or parallel to the semiconductor switch; and a drive circuit configured to drive the switching element. The switching element enters an off-state or an on-state depending on a control voltage input to a gate terminal, and the drive circuit includes two or more types of control voltages, as a control voltage at which the switching element enters an off-state.

Abstract: In one embodiment, a method includes identifying at a first powered device in communication with power sourcing equipment, a second powered device in communication with the first powered device, wherein the first powered device is receiving high voltage pulse power from the power sourcing equipment, notifying the power sourcing equipment of the second powered device at the first powered device, and performing a low voltage power initialization at the first powered device with the second powered device before passing the high voltage pulse power to the second powered device.

Abstract: A method includes detecting a first current flowing through a first clamping device coupled to a gate of a power switch, determining whether an inductor current reduces to zero based upon a first comparison between the first current and a first predetermined current level, and after determining the inductor current reduces to zero, determining whether a drain voltage of the power switch enters a valley of a resonant ringing based upon a second comparison between the first current and the first predetermined current level.

Abstract: The bidirectional insulating DC-DC converter shares high/low voltage terminals, a cooling passage, a housing, and a control board, and two independent step-down circuit (10) and step-up circuit (20) are formed in parallel to perform a bidirectional DC power conversion. A high voltage applied from a high voltage battery HV is stepped down through the step-down circuit (10) and output to a low voltage battery LV. On the other hand, a low voltage applied from the low voltage battery LV is stepped up through the step-up circuit (20) and output to the high voltage battery HV. The step-down circuit (10) is formed as an active clamp forward converter circuit, and the step-up circuit (20) is formed as an active clamp flyback converter circuit.

Abstract: A method for determining user configurations of services in a radio communication network is performed in a support system node, and includes ranking users of a service based on frequency of occurrences of user reconfiguration in the radio communication network, creating a linear regression model of user configuration for a plurality of users of the service in the radio communication network, identifying a user configuration per user of the service for a selected number of ranked users by fitting the selected number of ranked users in the linear regression model, in order to reduce user reconfiguration of the service, and providing the identified user configuration per user to the selected number of ranked users. A support system node, a computer program and a computer program for determining user configurations of services in a radio communication network are also presented.

Abstract: A power device fault detection circuit includes a first fault detector configured to measure an output signal of at least one power device and output a first fault signal when a voltage of the output signal of the at least one power device exceeds a first voltage reference level after a first time period; and a second fault detector configured to measure an output signal of the at least one power device and output a second fault signal when a voltage of the output signal of the at least one power device exceeds a second voltage reference level after a second time period, where the first time period implemented by the first fault detector is shorter than the second time period implemented by the second fault detector.

Abstract: A control circuit applied to a power adapter includes a voltage conversion unit and a switch control unit. The voltage conversion unit is configured to: receive a first direct current voltage, and generate a second direct current voltage based on the first direct current voltage, where when the first direct current voltage is lower than a working voltage of the switch control unit, the voltage conversion unit is configured to boost the first direct current voltage, to obtain the second direct current voltage. The switch control unit is configured to: receive the second direct current voltage from the voltage conversion unit, and use the second direct current voltage as a power supply voltage of the switch control unit.

Abstract: A power source apparatus including a control unit configured to output a control signal to a switching element to switch a target voltage of an output voltage from a transformer. In a case of increasing the output voltage, the control unit outputs the control signal having a first duty when the target voltage is lower than a first threshold value, and outputs the control signal having a second duty larger than the first duty when the target voltage is switched to a value equal to or higher than the first threshold value. In a case of reducing the output voltage, the control unit outputs the control signal having the second duty when the target voltage is equal to or higher than a second threshold value, and outputs the control signal having the first duty when the target voltage is switched to a value lower than the second threshold value.

Abstract: A charging device of the present invention includes a DC-DC converter, a charging circuit that charges a secondary battery, a power supply voltage detecting circuit that detects an input voltage Ve, an output voltage setting circuit that sets an output voltage of the DC-DC converter, and a charging control section that controls the charging circuit and the output voltage setting circuit based on the input voltage Ve, and the charging control section increases the output voltage of the DC-DC converter by a predetermined voltage in a stepwise manner while monitoring the input voltage Ve, and in a case where the input voltage Ve is decreased to a first threshold voltage Vth1 or less before the output voltage of the DC-DC converter increases to a rated charging voltage, the charging control section keeps the output voltage of the DC-DC converter at a voltage that is one step lower than a voltage at a time point of the case.

Abstract: A two-stage driver supplies current to an LED load. A first stage of the driver generates a bulk voltage. A second stage has a flyback transformer with a primary winding and a secondary winding. The second stage generates an output voltage to cause LED load current. The primary winding is turned on and off by a gating signal. Control logic within the second stage is responsive to initially turning on the driver to perform a startup short circuit test of the output circuit by applying a gating signal with a short on-time and a low switching frequency. If the output circuit is not shorted, the control logic increases the on-time and the switching frequency to detect if an output current is excessive. If the output current is not excessive, the control logic adjusts the on-time and the frequency to provide sufficient current to illuminate the LED load.

Abstract: In this invention we introduce the concept of energy injection in a resonant circuit with initial conditions which is part of almost all of the present topologies. The patent will present in details several methods of energy injection in a resonant circuit with initial conditions and how it is applies to different topologies. The patent presents also a simple and economical method of driving the clamp switch in a flyback topology operating in discontinuous mode and a bias circuit in a flyback topology wherein the output voltage varies over a large range.

Abstract: A power converter controller includes an analog to digital converter (ADC) to generate a digital representation of a feedback signal of a power converter, the feedback signal being received from a compensator of the power converter and being based on an output voltage of the power converter. A nonlinear gain block of the power converter controller receives the digital representation of the feedback signal and generates a transformed digital representation of the feedback signal using a nonlinear function. A switch control block of the power converter controller controls an on-time of a primary-side switch of the power converter based on the transformed digital representation of the feedback signal.

Abstract: A power supply control circuit for a switch mode power supply converter, and a power supply control method using the control circuit. The control circuit includes an auxiliary boosting unit, a main control unit and an auxiliary winding unit. The main control unit is configured to control the power switch in a power stage circuit to turn on or to be off, and to supply power to the auxiliary boosting unit. The auxiliary boosting unit is configured to provide auxiliary power for the main control unit, and to self-adaptively adjust the auxiliary boosting unit's own average switching frequency based on a load state of the main control unit. The auxiliary winding unit is configured to couple energy by means of a magnetic element in the power stage circuit, to generate an output voltage.

Abstract: A power converter provides a low-voltage output using a full-bridge fault-tolerant rectification circuit. The output circuit uses controlled switches as rectifiers. A fault detection circuit monitors circuit conditions. Upon detection of a fault, the switches are disabled decoupling the power converter from the system. A common-source dual MOSFET device includes a plurality of elements arranged in alternating patterns on a semiconductor die. A common-source dual synchronous rectifier includes control circuitry powered from the drain to source voltage of the complementary switch. A DC-to-DC transformer converts power from an input source to a load using a fixed voltage transformation ratio. A clamp phase may be used to reduce power losses in the converter at light loads, control the effective output resistance of the converter, effectively regulate the voltage transformation ratio, provide narrow band output regulation, and control the rate of change of output voltage for example during start up.

Abstract: A grounded voltage protection circuit for a linear drive circuit includes an AC-DC power supply module, a first voltage protection module, an LED module, a drive IC and a linear current adjustment module. Through the cooperation of the first voltage protection module, the drive IC and the linear current adjustment module, when a DC voltage signal output by the AC-DC power supply module exceeds a first preset voltage value, the first voltage protection module outputs the first preset voltage signal to prevent the drive IC and the LED module from being damaged due to the overvoltage output by the AC-DC module, and avoid the transient impulse voltage in the entire voltage protection circuit, thereby enabling the voltage protection circuit to pass the CEC certification.

Abstract: A power distribution system includes a plurality of power distribution modules connected to at least one power supply and configured to receive power therefrom. A power distribution bus connects the power distribution modules of the plurality of power distribution modules in parallel. The plurality of power distribution modules executes a distributed system policy management protocol over the power distribution bus to control a supply of available power from the at least one power supply to loads connected to USB charging ports of the power distribution modules.

Abstract: A two-stage driver supplies current to a light emitting diode (LED) load. The driver includes a first stage and a second stage. The second stage is configured to generate a desired current through the LED load. The second stage has a flyback converter having a flyback transformer with a primary winding and a secondary winding. The primary winding is turned on and off by a gating signal. An induced voltage in the secondary winding rings when a current in the secondary winding is discharged. The flyback converter is configured to turn on the primary winding only during a detected valley in the ringing of the secondary winding. If the primary winding is turned on during a detected valley different from the previous detected valley, a valley jump is detected and the switching frequency is adjusted.

Abstract: In a start-up control in which primary-side direct-current (DC) terminals and secondary-side DC terminals are charged by an external power supply outside a power conversion device, initially, one-side DC terminals are charged by the external power supply while switching operations of the primary-side bridge circuit and the secondary-side bridge circuit are stopped. Subsequently, a bridge circuit that is connected to the DC terminals not charged by the external power supply stops the switching operation and operates in a diode rectifying mode, while a bridge circuit that is connected to the DC terminals charged by the external power supply performs the switching operation and outputs an AC voltage whose voltage pulse width has been subjected to a variable control so that the voltage pulse width is smaller for a greater voltage difference of the charged DC terminals from the uncharged DC terminals.

Abstract: Apparatus and associated methods relate to providing an integrated circuit package having (a) a bypass circuit in parallel with an inductor and (b) a logic circuit configured to control the bypass circuit for conductivity modulation. In an illustrative example, in response to a corresponding load transient, the logic circuit may include a state machine configured to generate different control signals for the bypass circuit to control the timing and/or quantity of energy transfer from the inductor to a load. The bypass circuit may include a first semiconductor switch and a second semiconductor switch connected in anti-series. In some implementations, the power stage and the bypass circuit may be operated, for example, in numerous operational modes to dynamically modulate conductivity across the terminals of the inductor in a power supply to advantageously result in a smaller undershoot and overshoot.

Abstract: The present invention discloses a power converter, a switch control circuit, and a short circuit detection method for current sensing resistor of the power converter. The power converter includes: a transformer, a power switch, a current sensing resistor and a switch control unit. The current sensing resistor has one end coupled to the power switch and another end coupled to ground. The switch control unit generates the operation signal to control the power switch. The switch control unit generates a first sample-and-hold voltage at a first time point and a second sample-and-hold voltage at a second time point according to a voltage across the current sensing resistor. When a voltage difference between the first sample-and-hold voltage and the second sample-and-hold voltage is smaller than a reference voltage, it is determined that a short circuit occurs in the current sensing resistor.

Abstract: A power supply system comprises: a switched-capacitor converter, a transformer, and a voltage converter. The switched-capacitor converter includes multiple capacitors. The multiple capacitors are controllably switched in a circuit path including a primary winding of the transformer to convert the first voltage into a second voltage. The voltage converter converts the first voltage produced by the switched-capacitor converter into the second voltage that powers a load.

Abstract: An image forming apparatus controls a power supply circuit by supplying a control signal to the power supply circuit, and detects an electrical characteristic, e.g. an electrostatic capacitance generated between an image carrier and a developing member or a current caused to run by applying a development voltage to the developing member. The apparatus determines a change pattern of a duty ratio of a PWM signal including the control signal on the basis of the electrical characteristic. The apparatus changes the duty ratio as time passes according to the determined change pattern and outputs the control signal to the power supply circuit.

Abstract: A power factor correction (PFC) controller applied to a primary side of a power converter includes a feedback pin, a sensing pin, a current detecting circuit, an output voltage detecting circuit, and a determination circuit. The current detecting circuit is coupled to the feedback pin and the sensing pin for detecting an output current of a secondary side of the power converter according to a feedback voltage of the feedback pin and a sensing voltage of the sensing pin. The output voltage detecting circuit is coupled to the feedback pin for detecting an output voltage of the secondary side of the power converter according to the feedback voltage. The determination circuit is coupled to the current detecting circuit and the output voltage detecting circuit for turning on or turning off a PFC circuit coupled to the power converter according to the output current and the output voltage.

Abstract: A power supply circuit has a push-pull portion having a transformer; first and second terminals of the primary winding, each connected to ground via first and second switches; an inductor connected between an input voltage and the primary winding centre tap via a third switch; an energy storage portion connected between the primary winding and ground, and to the inductor via a fourth switch; a controller arranged to monitor the input voltage and to apply partially overlapping first and second PWM signals to the first and second switches; when input voltage is between first and second thresholds, the controller closes the third switch and opens the fourth switch; above the second threshold, the controller applies a third PWM signal to the third switch and opens the fourth switch; and below the first threshold, the controller closes the third switch and applies a fourth PWM signal to the fourth switch.

Abstract: A power supply control device includes a charge circuit, a detection circuit, and a charge control circuit. The charge circuit charges a capacitor coupled to a power supply voltage node based on a full-wave rectified voltage. The charge control circuit enables a charge mode of the charge circuit when the detection circuit detects that a power supply voltage is less than a first threshold voltage. The charge control circuit disables the charge mode when the detection circuit detects that the power supply voltage reached a second threshold voltage. The charge control circuit sets a charge capacity of the charge circuit in a second charge mode period according to a length of a first charge mode period.

Abstract: A circuit and method for providing high-voltage radio-frequency (RF) energy to an instrument at multiple frequencies includes a plurality of inputs each configured to receive an RF voltage signal oscillating at a corresponding frequency, and a step-up circuit for generating magnified RF voltage signals based on the received RF voltage signals. The step-up circuit includes an LC network operable to isolate the RF voltage signals at the plurality inputs from one another while preserving a voltage magnification from each input to a common output at each of the corresponding frequencies.

Abstract: A controller of a current resonance switching power supply apparatus configured to supply a constant output voltage to a load. The current resonance switching power supply apparatus includes a resonance circuit, and generates a feedback signal indicative of an error between the output voltage and a target voltage. The controller includes a load current detection circuit that receives a part of a resonance current of the resonance circuit, performs averaging and outputs a load current signal, and a standby detection circuit that receives the feedback signal and the load current signal, and determines that the load is in a standby mode upon detecting that the load current signal is lower than a first threshold and the feedback signal is lower than a second threshold, and is in a normal mode upon detecting that the feedback signal continues to be higher than the second threshold for more than a predetermined time.

Abstract: A control circuit for a switching converter having a main power switch and a freewheeling circuit, can be configured to: control the freewheeling circuit to be turned on in a first time interval after the main power switch is turned off; control the freewheeling circuit to be turned on in a second time interval after the first time interval, in order to reduce turn-on loss of the main power switch; and where the first time interval and the second time interval do not overlap each other in a switching cycle.

Abstract: A control circuit for a resonant converter has a communication interface, a memory, and a primary switching control circuit. The memory provides a frequency setting signal capable of being programmed through a communication interface, the primary switching control circuit provides a first control signal to control a high-side switch and a second control signal to control a low-side switch. When the resonant converter works in an open loop mode, a frequency of the first control signal and the second control signal is determined by the frequency setting signal, an on-time period of the high-side switch equals an on-time period of the low-side switch, less than half of a resonant period.