Abstract: A method can be used for controlling the switching operation of a switching power converter that includes a semiconductor switch coupled in series to an inductor. The switching power converter consumes an input current from a power supply and provides an output current to a load. In each switching cycle a switch-on time instant is detected for the semiconductor switch. The semiconductor switch is closed thus enabling, at the detected switch-on time instant, the input current passing through the semiconductor switch. The semiconductor switch is opened after a desired on-time, during which the input current rises from zero to a peak value, has passed. A time interval is detected, in which the instantaneous output current is not zero. A first value that represents the peak of the input current is obtained during the on-time.

Abstract: A primary-only power supply enables transmission of a signal or message from the secondary side of an isolated power supply to the primary side. To enable robust detection of the message without interfering with primary side sensing for output regulation, a configurable impedance current path is configured between the primary winding and ground. The primary side controller controls the configurable impedance current path to have a relatively low impedance during the normal mode and a relatively high impedance during the messaging mode.

Abstract: A power converter may include an amplifier that generates an error signal, a modulator that generates a modulated error signal, an isolator that generates an isolated modulated error signal, and a demodulator that generates an isolated error signal, which may be substantially proportional to the difference between the output signal and the reference signal, and a controller that controls a power stage to generate the output signal of the power converter.

Abstract: System and method for regulating a power converter. The system includes a comparator configured to receive a first signal and a second signal and generate a comparison signal based on at least information associated with the first signal and the second signal. The first signal is associated with at least an output current of a power converter. Additionally, the system includes a pulse-width-modulation generator configured to receive at least the comparison signal and generate a modulation signal based on at least information associated with the comparison signal, and a driver component configured to receive the modulation signal and output a drive signal to a switch to adjust a primary current flowing through a primary winding of the power converter. The modulation signal is associated with a modulation frequency corresponding to a modulation period.

Abstract: A controller having an on-time controller, an off-time controller, a switch control signal generator, and a jittering signal generator, wherein the jittering signal generator couples jitter into the on-time or the off-time of a primary switch of the power supply. Therefore the EMI performance may be improved.

Abstract: Switching-mode power conversion system and method thereof. The system includes a primary winding configured to receive an input voltage and a secondary winding coupled to the primary winding. Additionally, the system includes a compensation component configured to receive the input voltage and generate at least a clock signal based on at least information associated with the input voltage, and a signal generator configured to receive at least the clock signal and generate at least a control signal based on at least information associated with the clock signal. Moreover, the system includes a gate driver configured to receive at least the control signal and generate a drive signal based on at least information associated with the control signal, and a first switch configured to receive the drive signal and affect a first current flowing through the primary winding.

Abstract: A power converter controller includes a primary controller that is galvanically isolated from a secondary controller. The primary controller controls a state of a power switch during a first mode of operation according to a switching pattern defined by the primary controller. During a second mode of operation, the primary controller controls the state of the power switch in response to control signals received via a communication link. The secondary controller operates in a powered down state during the first mode of operation. The secondary controller initiates a transition operation with the primary controller that transitions the primary controller and the secondary controller from the first mode of operation to the second mode of operation. In the second mode of operation, the secondary controller transmit the control signals to the primary controller via the communication link.

Abstract: A power converter controller includes a primary controller and a secondary controller. The primary controller is coupled to receive one or more request signals from the secondary controller and transition a power switch from an OFF state to an ON state in response to each of the received request signals. The primary controller is coupled to detect a turn-off condition when the power switch is in the ON state and transition the power switch from the ON state to the OFF state in response to detection of the turn-off condition. The secondary controller is galvanically isolated from the primary controller. The secondary controller is coupled to transmit the request signals to the primary controller and control the amount of time between the transmission of each of the request signals.

Abstract: A power distribution system includes controller of a switching power converter to control the switching power converter and determine one or more switching power converter control parameters. In at least one embodiment, the switching power converter utilizes a transformer to transfer energy from a primary-side of the transformer to a secondary-side of the transformer. In at least one embodiment, the switching power converter control parameters includes a secondary-side conduction time delay that represents a time delay between when the primary-side ceases conducting a primary-side current and the secondary-side begins to conduct a secondary-side current. In at least one embodiment, determining and accounting for this secondary-side conduction time delay increases the prediction accuracy of the secondary-side current value and accurate delivery of energy to a load when the controller does not directly sense the secondary-side current provided to the load.

Abstract: A secondary control circuit includes a voltage regulator circuit to be coupled to an output of a power converter to provide a regulated power supply. One or more switched loads is coupled between a first terminal to be coupled to the output of the power converter and an output ground terminal. One or more comparator circuits is coupled to a second terminal coupled to receive an output sense signal. Each one of the one or more comparator circuits is coupled to receive a respective one of one or more reference signals. Each respective one of the one or more reference signals is a scaled representation of a first one of the one or more reference signals. Each one of the one or more switched loads is coupled to be switched in response to an output of a respective one of the one or more comparator circuits.

Abstract: An exemplary power conversion system includes a power converter and a protection circuit coupled with the power converter. The power converter is configured to convert an input power into an output power. The power converter includes an isolator magnetically coupling a primary side and a secondary side and at least one primary switch coupled in series with the primary side. The at least one primary switch is configured to turn on or turn off current to the isolator on the primary side. The protection circuit is coupled to the at least one primary switch. The protection circuit includes a detecting device for detecting switch state of a secondary switch on the secondary side. The detecting device is configured to drive the at least one primary switch according to the detected switch state. A method for operating the power conversion system is also described.

Abstract: A control system for a power converter with reduced power dissipation and method of operating the same. In one embodiment, the control system includes a first controller coupled to a primary winding of a transformer and configured to control a duty cycle of a power switch to regulate an output characteristic of the power converter. The control system also includes a second controller configured to provide a signal to one of a secondary winding of the transformer and a circuit element spanning an isolation boundary of the transformer in response to a dynamic change of the output characteristic to trigger the first controller to initiate the duty cycle for the power switch.

Abstract: An apparatus and method for a flyback power converter reduce the standby output voltage of the flyback power converter by switching the reference voltage provided by a shunt regulator of the flyback power converter or the ratio of voltage divider resistors of the shunt regulator, to reduce the standby power consumption by an output feedback circuit of the flyback power converter, the shunt regulator, and the voltage divider resistors, and thereby improve the power loss of the flyback power converter in standby mode.

Abstract: The present invention discloses a switching regulator, including: a power stage including at least one power transistor which switches according to a switch control signal to convert an input voltage to an output voltage; a pulse width modulation (PWM) signal generator generating a PWM signal according to the output voltage; an over current detection circuit comparing a current sensing signal with a reference signal to generate an over current signal indicating whether an over current is occurring; and a signal adjustment circuit adjusting the PWM signal or a clock signal to generate the switch control signal for controlling an ON time of the power transistor of the power stage.

Abstract: A power converter with reduced power dissipation at light loads and method of operating the same. In one embodiment, the power converter includes an opto-isolator circuit configured to produce an output signal dependent on an output characteristic of the power converter. The power converter also includes a controller configured to control the output characteristic to a first regulated value when the output signal is greater than or equal to a threshold level, and control the output characteristic to a second regulated value less than the first regulated value when the output signal is less than the threshold level.

Abstract: A circuit for controlling a programmable power converter is provided. The circuit comprises a control circuit, a switching controller, and a first opto-coupler. The control circuit generates a programmable voltage-reference signal for regulating an output voltage of the programmable power converter. A feedback circuit of the control circuit detects the output voltage for generating a feedback signal in response to the programmable voltage-reference signal and the output voltage. The switching controller detects a switching current of a transformer for generating a switching signal coupled to switch the transformer for generating the output voltage and an output current in response to the feedback signal and the switching current of the transformer. The first opto-coupler transfers the feedback signal from the control circuit to the switching controller. The control circuit is at the secondary side of the transformer and the switching controller is at the primary side of the transformer.

Abstract: A dual-mode switching power control device includes an electric transformer, a PWM driving controller, a switching transistor, an isolation element, an output diode and an output capacitor. The PWM driving controller is connected to the switching transistor coupled to the electric transformer. The first side inductor of the electric transformer and the switching transistor are coupled to an input power, and the second side inductor of the electric transformer is coupled to the output diode. The output capacitor and a load are connected in series. The output power is converted into a feedback signal by the isolation element. The PWM driving controller determines to perform DCM or CCM based on the feedback signal to control the current flowing through the electric transformer, and the output power is generated. Therefore, the efficiency of power conversion is improved and is suitable for high power applications.

Abstract: A control circuit of an isolated flyback power converter providing bidirectional communication. The control circuit includes a pulse width modulation circuit, an oscillator, a primary transceiver, a secondary error amplifier and a secondary transceiver. The primary transceiver generates a feedback signal and a pulse-position signal. The secondary error amplifier generates an error signal in accordance with an output voltage of the power converter. The secondary transceiver generates a pulse modulation signal for transmitting the data from the secondary side to the primary side, and generates a frequency signal in response to a switching voltage of the transformer. The frequency signal is demodulated as the data transmitted from the primary side to the secondary side. The feedback signal is correlated to the error signal. The pulse-position signal is correlated to the pulse modulation signal. The error signal and the pulse modulation signal are coupled to an input of an optical coupler.

Abstract: A power converter employing a control system configured to make multiple functional use of a circuit node therein and method of operating the same. In one embodiment, the power converter includes a power train including at least one power switch. The power converter also includes a control system including an opto-isolator circuit, including a resistor, configured to receive an output signal from the power converter and provide a feedback signal to a feedback node for the control system to provide a switch control signal for the at least one power switch. The control system also includes a current source configured to produce multiple voltage levels at the feedback node in accordance with the resistor, thereby enabling multiple functional uses of the feedback node.

Abstract: A reverse shunt regulator includes a MOSFET connected between a cathode and an anode, a switch and a current source serially connected between the cathode and the anode, and an error amplifier having a positive input node to receive an internal reference voltage, a negative input node connected to the reference electrode, and an output node connected to a control electrode of the MOSFET. When the voltage of the reference electrode is within a range, the larger the voltage of the reference electrode is, the less the current of the MOSFET is. Application of this reverse shunt regulator to a flyback converter for output feedback will reduce the power loss in a green mode of the flyback converter.

Abstract: An improved valley-mode switching (VMS) scheme and circuitry for implementing the improved VMS switching scheme in a switch-mode power converter are disclosed. For a given switching cycle, a desired switch turn-on time is determined based on a pulse width modulation, pulse frequency modulation, or other suitable power converter control scheme. Also, one or more times corresponding to local minimums (valleys) are predicted for the voltage across a power switch of the switching power converter. The power switch is turned on at a valley immediately subsequent or otherwise subsequent to the desired switch time determined according to the power converter control scheme. Thus, the improved VMS scheme enables low-voltage switch operation to reduce switching loss and EMI noise without restricting the control scheme of the power converter.

Abstract: A controller of a power converter is provided. The controller includes a feedback circuit, an output circuit, and a clamping circuit. The feedback circuit generates a feedback signal in accordance with output of the power converter. The output circuit generates a switching signal in accordance with the feedback signal for regulating the output of the power converter. The clamping circuit limits the feedback signal under a first level for a first load condition and limits the feedback signal under a second level for a second load condition. The clamping circuit includes a timer circuit. The timer circuit determines a slew rate of the feedback signal for increasing the feedback signal from the first level to the second level, and the second level is higher than the first level.

Abstract: The present invention provides an isolated regulating power converter with opto-coupled feedback of output (Vo) with respect to a reference level (Vset) for regulation to a converter controller. The sense of the feedback signal is such that the opto-coupler LED is ON when Vo<Vset and OFF when Vo>Vset with the effect that the LED current and power loss is zero during the times when Vo>Vset, as is normal case for many controllers at low or no load. This saves power under such circumstances. Additionally, as the LED does not load the output during this time, the proportion of time for which Vo>Vset is increased, meaning that the timing at which the switch must again be on to meet demand is extended, producing a further power saving.

Abstract: An example integrated circuit for use in a power supply includes a feedback terminal, a controller and a clamp. The feedback terminal is to be coupled to receive a feedback signal that is representative of a bias voltage across a bias winding of the power supply. The controller is to be coupled to control switching of a power switch included in the power supply in response to the feedback signal. The clamp is coupled to clamp the feedback terminal to a voltage for at least a time that the bias voltage is negative with respect to an input return of the power supply.

Abstract: An isolated power converter, an inverting type shunt regulator, and an operating method thereof are disclosed. The isolated power converter includes a transformer, an inverting type shunt regulator, a controller, and an optocoupler. The inverting type shunt regulator is located on the secondary side of the transformer. The inverting type shunt regulator includes an error amplifier and a MOSFET. The controller is located on the primary side of the transformer. The controller includes an inverting unit cooperated with the MOSFET. The controller receives a feedback voltage. The optocoupler is coupled to the inverting type shunt regulator and the controller to provide an opto-coupling current to the controller.

Abstract: A controller for generating jitters in a constant current mode of a power converter includes a current pin, an auxiliary pin, a constant current control unit, and a control signal generation unit. The current pin is used for receiving a primary side voltage determined according to a resistor and a primary side current flowing through the power converter. The auxiliary pin is used for receiving a voltage corresponding to an auxiliary winding of the power converter. The constant current control unit is used for generating an adjustment signal according to the primary side voltage, a discharge time corresponding to the voltage, and a reference voltage. The reference voltage has a predetermined range jitter voltage. The control signal generation unit is used for adjusting a period of a gate control signal according to the adjustment signal.

Abstract: Methods for flyback converters are provided. The method, adopted by a flyback converter circuit including a transformer, including: determining an output voltage output from a secondary circuit of the transformer; feeding a feedback voltage based on the output voltage from the secondary circuit back to a primary circuit of the transformer; increasing a current limit and a switching frequency of a primary current with the feedback voltage; and supplying the primary current to a primary winding of the transformer.

Abstract: An exemplary power supply circuit for providing a driving voltage to a load includes a pulse width modulation (PWM) control circuit, a transformer, a voltage output terminal, and a temperature compensation circuit. The PWM control circuit is configured for outputting a pulse signal. The transformer is configured for converting a first direct current (DC) voltage to a second DC voltage according to the pulse signal. The voltage output terminal is configured for outputting the driving voltage based on the second DC voltage. The temperature compensation circuit includes a temperature sensor for detecting an operation temperature of the load and correspondingly generating a detecting signal, and a feedback signal transmitter for outputting a feedback signal based on the detecting signal. The PWM control circuit adjusts a duty ratio of the pulse signal according to the feedback signal outputted by the temperature compensation circuit.

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: A voltage control method for a power converter includes: acquiring a current of a first primary side winding of a transformer circuit of the power converter; integrating the acquired current to obtain an average voltage; comparing the average voltage with a reflected voltage associated with a current of a secondary side winding of the transformer circuit; and adjusting a duty cycle of a switch of the power converter based on an obtained comparison result for adjustment of an output voltage of the power converter.

Abstract: A power converter circuit may convert alternating current signals into direct current signals. A load may be powered from output terminals that are provided with the direct current signals. The power converter circuit may have a transformer with primary and secondary sides. A transistor on the primary side may be controlled using a pulse width modulation controller. A diode may be coupled in series with the secondary side of the transformer and the load. To improve efficiency at larger load currents, a synchronous rectifier control circuit may modulate a transistor on the secondary side that is coupled in parallel with the diode. The synchronous rectifier control circuit may monitor voltage pulses on the transistor on the secondary side or may make direct load current measurements to ascertain how much load current is flowing. Under low or no load conditions, synchronous rectification can be inhibited to improve efficiency.

Abstract: An example embodiment relates to a switched-mode power supply comprising a transformer with a first winding and a second winding. There is a transmitter configured to: detect a detectable variable (Vout) at the first winding, generate a transformer relayed signal in accordance with the detectable variable (Vout), and provide the transformer relayed signal to the first winding. A receiver is configured to: receive the transformer relayed signal from the second winding, and control a controllable variable at the second winding in response to the transformer relayed signal, wherein the transformer relayed signal is a symbol stream comprising a plurality of symbols.

Abstract: A power factor improvement circuit includes a low frequency filter unit installed between two electrodes of an output terminal of a rectifier unit for adjusting voltage and current inputted to a PWM control IC in-phase, and first and second compensation circuits installed at a current compensation terminal and a voltage compensation terminal of the PWM control IC respectively, and the first and second compensation circuits are provided for reducing the current gain of the phase adjustment unit to avoid any unnecessary action of the PWM control IC, so as to achieve the effect of controlling a power factor to a level over 0.90 when a full voltage of 90-264V is inputted.

Abstract: A power adapter comprises a main power circuit, a feedback circuit, an ID detection circuit and a switch controller. The feedback circuit is coupled to the main power circuit for detecting the DC output voltage and issuing a feedback signal. The ID detection circuit is coupled to the feedback circuit for detecting an ID signal from the DC-powered electronic device and issuing a control signal to the feedback circuit to disable or delay the feedback signal for a specific time period, and comparing a dropping slew rate of the DC output voltage with a preset value to issue a hiccup mode control signal. The switch controller is configured for controlling the operations of the main power circuit in response to the feedback signal and controlling the power adapter to operate in a normal operation mode or a hiccup mode in response to the hiccup mode control signal.

Abstract: There are provided a shunt regulator having a protection function to detect an abnormal state, and a power supply device having the same. The shunt regulator of a power supply device in which a primary side and a secondary side have grounds having different electrical characteristics and are electrically insulated from one another, and power switched from the primary side is induced to the secondary side so as to be output, includes: a comparator positioned on the secondary side and comparing a voltage output from the power supply device with a preset reference voltage; and a first switch performing a control to stop supply of driving power required for a power switching operation of the primary side according to a comparison result from the comparator.

Abstract: A power converter includes a transformer with a primary and a secondary winding. Feedback and control is maintained on the primary-side while a separate load detection circuit detects dynamic load conditions on the secondary-side. The load detection circuit detects dynamic load conditions at the time when a load is connected to the output of the switching power converter and, in turn, generates an alert signal. A coupling circuit coupled to the load detection circuit at the secondary winding side of the transformer and to the controller at the primary winding side of the transformer transmits the alert signal to the controller. The controller regulates the output voltage based on the feedback signal generated at the primary side of the transformer while detecting and responding to the dynamic load condition based on the alert signal generated at the secondary side of the transformer.

Abstract: A controller includes a current sense circuit and a voltage regulation circuit. The current sense circuit generates a first signal that indicates whether a current through a sense terminal exceeds a first threshold current level, which indicates a fault condition of a power converter. The voltage regulation circuit regulates the sense terminal to a first voltage level when the current through the terminal is less than the first threshold current level and regulates the sense terminal to a second voltage level when the current exceeds the first threshold current level. The current sense circuit generates a second signal that indicates whether the current through the sense terminal exceeds a second threshold current level while the sense terminal is regulated to the second voltage level. The response circuit generates an output signal that determines a response of the controller to the fault condition based on the second signal.

Abstract: A current regulation apparatus is provided. The current regulation apparatus includes a trans unit, a first switching unit, a voltage detection unit, a voltage comparison unit, and a control unit. The trans unit includes an auxiliary winding unit. The first switching unit controls an operation of the trans unit. The voltage detection unit detects a voltage induced to the auxiliary winding unit. The voltage comparison unit compares a voltage detected by the voltage detection and a reference voltage. The control unit adjusts a turn-on section of the first switching unit according to an output voltage of the voltage comparison unit.

Abstract: A control circuit for a resonant power converter and a control method thereof are disclosed. The control circuit comprises a first transistor and a second transistor switching a transformer through a resonant tank. A controller receives a feedback signal for generating a first switching signal and a second switching signal coupled to drive the first transistor and the second transistor respectively. The feedback signal is correlated to an output of the resonant power converter. A diode is coupled to the second transistor for detecting the state of the second transistor for the controller. The first switching signal and the second switching signal are modulated to achieve a zero voltage switching (ZVS) for the second transistor.

Abstract: A switching power supply device including: a transformer configured to include a primary winding, a secondary winding, and an auxiliary winding; a switching unit configured to switch a current that flows through the primary winding of the transformer; a control unit configured to control a switching operation of the switching unit; a starting resistor connected between a voltage input side of the primary winding and a power supply terminal of the control unit; a voltage supply unit configured to rectify and smooth a voltage output from the auxiliary winding and supply the resultant to the power supply terminal; and an activation control unit configured to control activation timing of the control unit by inputting a voltage to an ON/OFF terminal of the control unit, the activation control unit being connected between the voltage input side of the primary winding and a ground side of the auxiliary winding.

Abstract: A control circuit of a resonant power converter is disclosed. The control circuit comprises a first transistor and a second transistor for switching a transformer and a resonant tank comprising a capacitor and an inductor. A controller is configured to receive a feedback signal correlated to the output of the power converter for generating a first switching signal and a second switching signal to drive the first transistor and the second transistor, respectively. A diode coupled to the first transistor and the resonant tank for detecting the state of the first transistor and generating a detection signal for the controller. The detection signal indicates if the transistors are in a zero voltage switching (ZVS) state. If the transistors are not in the ZVS state, the switching frequency of the transistors will be increased.

Abstract: A switching power supply device control circuit and switching power supply can combat fluctuation due to the input voltage in the peak current of a switching element, even when using an oscillator. A control IC is connected to a switching element and to a current detecting resistor, and controls the switching element, the control IC being configured of an OCP comparator that detects an overcurrent with respect to a load, an overcurrent level setting circuit that corrects a fluctuation occurring in the peak current of the switching element in response to the output voltage from the AC input, an oscillator having a frequency modulating function whereby the switching frequency with respect to the switching element can be modulated, and a slope compensation circuit that generates a slope compensation signal increasing monotonically in proportion to the time from the start of each cycle of an oscillating signal of the oscillator.

Abstract: A synchronous rectifier for a switching power converter is provided and includes a power transistor, a diode, and a control circuit. The power transistor and the diode are coupled to a transformer and an output of the power converter for the rectification. The control circuit generates a drive signal to switch on the power transistor once the diode is forward biased. The control circuit includes a phase-lock circuit. The phase-lock circuit generates an off signal to switch off the power transistor in response to a pulse width of the drive signal. The pulse width of the drive signal is shorter than a turned-on period of the diode. The phase-lock circuit further reduces the pulse width of the drive signal in response to a feedback signal. The feedback signal is correlated to an output load of the power converter.

Abstract: An electronic system and method include a controller to operate in a start-up mode to accelerate driving a load to an operating voltage and then operates in a post-start-up mode. A start-up condition occurs when the controller detects that a load voltage is below a predetermined voltage threshold level. The predetermined voltage threshold level is set so that the controller will boost the voltage to an operating value of a load voltage at a faster rate than during normal, steady-state operation. The controller causes a switching power converter to provide charge to the load at a rate in accordance with a start-up mode until reaching an energy-indicating threshold. When the energy-indicating threshold has been reached, the controller causes the switching power converter to (i) decrease the amount of charge provided to the load relative to the charge provided during the start-up mode and (ii) operate in a distinct post-start-up-mode.

Abstract: System and method for regulating an output current of a power conversion system. An example system controller for regulating an output current of a power conversion system includes a driving component, a demagnetization detector, a current-regulation component, and a signal processing component. The driving component is configured to output a drive signal to a switch in order to affect a primary current flowing through a primary winding of the power conversion system. The demagnetization detector is configured to receive a feedback signal associated with an output voltage of the power conversion system and generate a detection signal based on at least information associated with the feedback signal. The current-regulation component is configured to receive the drive signal, the detection signal and a current-sensing signal and output a current-regulation signal based on at least information associated with the drive signal, the detection signal, and the current sensing signal.

Abstract: System and method for regulating a power conversion system. For example, a system controller includes a signal generator and one or more power-consumption components. The signal generator is configured to receive a feedback signal related to an output signal of the power conversion system, a current sensing signal and an input voltage, and to generate a control signal based on at least information associated with the feedback signal, the current sensing signal and the input voltage. The power-consumption components are configured to receive the control signal. The signal generator is further configured to determine whether the feedback signal is smaller than a feedback threshold for a first predetermined period of time, the current sensing signal is smaller than a current sensing threshold for a second predetermined period of time, and the input voltage is smaller than a first threshold for a third predetermined period of time in magnitude.

Abstract: A controller for a power converter is provided. The controller includes a sense current integrating circuit, a reference current integrating circuit and a drive signal generation circuit. The sense current integrating circuit performs an integrating operation to a sense current representative of a conduction current flowing through a power switch of the power converter and thereby outputs a first integrating result. The reference current integrating circuit performs another integrating operation to a reference current and thereby outputs a second integrating result. The drive signal generation circuit determines a switching period of the power switch according to a status of an output voltage of the power converter cooperative with a relative magnitude relationship between the first integrating result and the second integrating circuit. Furthermore, a controlling method for such power converter also is provided.

Abstract: A method of operation for flyback power converter includes operating a controller of the flyback power converter in a regulation mode when a control signal is below a first threshold. The control signal is provided as an input to a terminal of the flyback power converter. When the control signal is below a second threshold and above the first threshold, the controller is operated in a limiting mode. The controller is operated in an external command mode when the control signal is below a third threshold and above the second threshold. Lastly, when the control signal is above the third threshold, the controller is operated in a protection mode.

Abstract: A control circuit for a switched-mode power supply having an input side (101) connectable to an electrical power source and an output side (102) connectable to a load.

Abstract: A regulation circuit with the output cable compensation is developed for a power converter. It includes an error amplifier for generating a feedback signal in accordance with an output of the power converter. A compensation circuit is coupled to a transformer of the power converter for generating a compensation signal in response to a transformer signal generated by the transformer. The feedback signal is applied to generate a switching signal for switching the transformer and regulating the output of the power converter. The compensation signal is coupled to modulate the feedback signal for compensating a voltage drop of the output cable of the power converter.