Abstract: A control method and device of a voltage converter and a voltage control system are provided. In some embodiments, the control device includes a first control module configured to obtain a current reference value according to an output voltage of a voltage converter and a given voltage value; a current modulation module configured to reduce the current reference value when an output current of a voltage converter is greater than a first current threshold; and a second control module configured to control the output current of a voltage converter according to the reduced current reference value and an output current.

Abstract: A conversion device includes a primary side circuit, a secondary side circuit, a transformer, and a control circuit. The primary side circuit includes a primary side switch and is configured to receive an input voltage. The secondary side circuit outputs an output voltage to a load. The transformer comprises a primary winding and a secondary winding, the primary winding is electrically coupled to the primary side circuit and the secondary winding electrically coupled to the secondary side circuit. The control circuit is configured to control a peak value of the current of the primary side switch, to be limited in a band range.

Abstract: The present disclosure relates to an apparatus for adjusting AC-DC converter output voltage, the apparatus includes a plurality of ports, an AC-DC converter circuit, a plurality of DC-DC converters coupled to a plurality of controllers, where the plurality of controllers coupled to corresponding plurality of ports to operate the one or more loads, wherein at least one controller is a master controller and the other plurality of controllers are slave controllers. The master controller configured to determine, from the slave controllers power levels for each port, calculate an optimal input voltage value for the DC-DC converters and communicate the calculated value to the AC-DC converter circuit through a constant current source to regulate the amount of DC voltage that is being supplied to the DC-DC converters to operate the one or more loads, thereby leading to improved system efficiency of multiport USB based power adapter.

Abstract: An isolated power converter can include: a primary side having a primary winding and a primary power transistor; a secondary side having a secondary winding and a secondary power transistor; a secondary control circuit configured to change a voltage across the secondary winding to change a voltage across the primary winding during a period when both the primary power transistor and the secondary power transistor are in a turn-off state; and a primary control circuit configured to control switching states of the primary power transistor, such that an output signal of the isolated power converter matches an output demand.

Abstract: A laser system comprising high voltage AC-to-DC power converter and one or more current sources coupled to the high voltage AC-to-DC power converter without a DC-to-DC converter between the one or more current sources and the AC-to-DC power source. Each of the one or more current sources includes a high voltage switch and one or more independent safety shutoffs. A laser module is operably coupled to the one or more current source and configured to emit electromagnetic radiation wherein the one or more safety shutoffs are configured to disable emission of electromagnetic radiation from the laser module when triggered.

Abstract: An isolated converter has a constant voltage mode and a constant current mode. The isolated converter includes a transformer, a main switch, a driver, a controller, and an isolator. The controller includes a constant current control unit, a voltage comparator, and a control logic unit. The constant current control unit generates a voltage adjustment signal to adjust the reference voltage or voltage feedback signal according to a current feedback signal for sensing the output current. The control logic unit generates a trigger signal according to the comparison signal of the voltage comparator. The isolator connects the output terminal of the controller and the driver. The input terminal is used to transmit the trigger signal to the input terminal of the driver. The isolated converter can provide excellent constant voltage transient response and stable constant current regulation according to load conditions by improving the controller.

Abstract: The disclosure provides a starting circuit of a switching power supply, which includes an input rectifying and filtering circuit, a starting circuit, a transformer, an output rectifying and filtering circuit, a feedback circuit, a first photoelectric coupler and a power management chip. The power management chip is respectively connected with the output end of the first photoelectric coupler, the output end of the feedback circuit and the primary coil of the transformer. After the first photoelectric coupler is powered on, the starting circuit is turned on, and the power management chip and the transformer are started and work. After the first photoelectric coupler is powered off, the power management chip stops working and enters a standby state. And at the moment, the standby power consumption of the power management chip is equal to zero.

Abstract: This switching power supply device having a plurality of power supply circuits to be connected to a multi-phase power supply, is provided with: a first substrate on which an electric component constituting a filter circuit is mounted, the output end of the filter circuit being provided on one end side in a first direction; a second substrate on which a power semiconductor constituting a circuit provided at a stage later than the filter circuit is mounted, the input end of the circuit provided at the stage later than the filter circuit being provided on one end side in a second direction that intersects with the first direction; and a third substrate which is disposed between the first substrate and the second substrate, and on which a wiring pattern for electrically connecting the output end to the input end is formed.

Abstract: An electric power conversion system includes: an AC-DC conversion circuit converting AC charging power into DC power; a motor including a plurality of coils, one end of each being connected to a neutral point; a first switching device selectively allowing or blocking supply of output power from the AC-DC conversion circuit to the neutral point; an inverter including a plurality of motor connection terminals connected to the other ends of the coils of the motor, respectively, DC connection terminals including a positive terminal and a negative terminal, and a plurality of switching elements forming electrical connections between the DC connection terminals and the plurality of motor connection terminals; a battery connected to the DC connection terminals of the inverter; and a controller controlling operations of the AC-DC conversion circuit, the first switching device, and the inverter in accordance with whether or not the battery is charged.

Abstract: An apparatus for controlling a low-voltage DC-to-DC converter of a vehicle for converting high-voltage power into low-voltage power may include a signal selector for selecting and outputting one of a charging-oriented voltage command for charging the battery or a preset burst mode voltage command for operation of the low-voltage DC-to-DC converter in a burst mode in which the battery cannot be charged, a battery charge/discharge current limiter for generating a voltage command compensation value for limiting charge current of the battery when the signal selector outputs the charging-oriented voltage command and limiting discharge current of the battery when the signal selector outputs the burst mode voltage command, and a controller for controlling an output voltage of the low-voltage DC-to-DC converter to follow a compensated voltage command generated by applying the voltage command compensation value to the voltage command output by the signal selector.

Abstract: An inductive charging circuit coupled to a winding of a power converter and a supply terminal of a controller of the power converter. The inductive charging circuit comprising an input coupled to the winding, the input coupled to receive a switching voltage generated by the power converter, an inductor coupled to the input to provide an inductor current in response to the switching voltage, a first diode coupled to the inductor to enable the inductor current to flow from the input of the inductive charging circuit to an output of the inductive charging circuit; and the output of the inductive charging circuit coupled to the supply terminal of the controller, the output of the inductive charging circuit configured to provide an operational current responsive to the inductor current to the controller, the controller is configured to control a power switch of the power converter to generate the switching voltage.

Abstract: A resonant power converter is disclosed with a method of limiting output current therefrom. A switch operating frequency is regulated to provide output current to a load, wherein an error signal corresponds to a difference between the output current and a reference value. The error value is fed back to switch operating frequency control circuit via an optocoupler. A maximum detector diode current for the optocoupler is clamped to a maximum value when the error signal exceeds or equals a clamping threshold value. The clamping threshold value may correspond to a maximum output current at a maximum normal operating temperature, wherein the method utilizes the relationship between ambient temperature and the current transfer ratio (CTR) for the optocoupler. The CTR decreases when the detector diode current is clamped, which decreases output current and output power, reducing power loss in the enclosure and relieving thermal stress at high temperatures.

Abstract: A sleep-wake control circuit using a D-type flip-flop with a Schmitt trigger to detect pulse wake-up signal transitions. The sleep-wake control circuit comprises a sleep command input channel, a wake command input channel, and a D-type flip-flop. The D-type flip-flop is configured to receive a signal to switch to sleep mode from the sleep command input channel as a clock signal and to receive a wake event signal to switch to wake mode from the wake command input channel as a clear signal, such that a wake event signal from the wake command input channel takes priority over a sleep event signal from the sleep command input channel. The sleep command input channel and the wake command input channel are configured to include Schmitt triggers so as to detect pulse input signals.

Abstract: A power supply apparatus includes a voltage conversion circuit, a reference voltage generating circuit, a constant current control circuit which includes a current controller and a differential circuit which controls the current controller based on the reference voltage and current detection voltage showing a size of the output current, and wherein an electric current on the current path is controlled by the current controller a reference voltage adjustment circuit which adjusts a first reference voltage generated by the reference voltage generating circuit to converge a ripple occurring in the output current to a predetermined ripple rate or less, based on a voltage of a first potential point set on the current path from an output portion on a high potential side of the voltage conversion circuit to the current controller and a control voltage of the current controller.

Abstract: An LED (Light Emitting Diode) drive circuit includes a magnetic device, a power transistor, a current-sense resistor, and a controller. The magnetic device has a first terminal for receiving an input voltage derived from an input of the LED drive circuit, and a second terminal. The magnetic device generates an output current to drive at least one LED. The power transistor has a drain coupled to the second terminal of the magnetic device, a control terminal, and a source. The current-sense resistor has a first terminal coupled to the source of the power transistor for forming a current input signal, and a second terminal coupled to ground. The controller generates a switching signal coupled to control the power transistor to switch current through the magnetic device based on both a programmable signal derived from the input of the LED drive circuit, and the current input signal.

Abstract: A power system for an automotive vehicle includes a matrix transformer having two separate cores, a primary winding wound around each of the cores, a first secondary winding wound around one of the cores, and a second secondary winding galvanically isolated from the first secondary winding and wound around the other of the cores. The power system also includes circuitry that transfers power from an AC source to the primary winding, transfers power from the first secondary winding to a traction battery, and transfers power from the second secondary winding to an auxiliary battery.

Abstract: A programmable discrete input module is described. In one or more implementations, the programmable discrete input module comprises a pulse width modulation module configured to generate a pulse width modulated signal based upon an input signal and a pulse width demodulation module configured to generate a demodulated pulse width signal. An isolator is configured to isolate the pulse width modulation module and the pulse width demodulation module and to generate isolated modulated pulse width signal based upon the pulse width modulated signal for the pulse width demodulation module to generate the demodulated pulse width signal. The programmable discrete input module also includes a first comparator and a second comparator for comparing the demodulated pulse width signal with a respective programmable reference and a digital filter configured to filter a comparison signal output by the first comparator or the second comparator to generate a discrete input signal.

Abstract: An apparatus for a frequency characterization of an electronic system is provided. The apparatus includes two terminals configured to couple with the electronic system. Further, the apparatus includes a control circuit configured to generate a test signal. The apparatus further includes a coupling circuit including an adjustable impedance and a switch which are coupled in series. End nodes of the coupling circuit are coupled to the two terminals. The switch is configured here to electrically couple the two terminals with each other based on the test signal.

Abstract: A system includes a primary field effect transistor (FET) coupled to a primary winding on a primary side of an alternating current-to-direct current (AC-DC) converter. The system also includes a gate driver, coupled to the primary FET, that is to, in response to a signal received from a startup controller of the AC-DC converter, turn on the primary FET. The gate driver includes a voltage bias p-type metal-oxide-semiconductor (VBP) buffer coupled between an external supply voltage and a VBP portion of driving chain circuitry, the driving chain circuitry to drive a gate of the primary FET. The gate driver also includes a voltage bias n-type metal-oxide-semiconductor (VBN) buffer coupled between a VBN regulator, which generates an internal supply voltage, and a VBN portion of the driving chain circuitry.

Abstract: System and method for regulating a power conversion system. An example system controller for regulating a power conversion system includes a first controller terminal associated with a first controller voltage and coupled to a first transistor terminal of a first transistor, the first transistor further including a second transistor terminal and a third transistor terminal, the second transistor terminal being coupled to a primary winding of a power conversion system, a second controller terminal associated with a second controller voltage and coupled to the third transistor terminal, and a third controller terminal associated with a third controller voltage. The first controller voltage is equal to a sum of the third controller voltage and a first voltage difference. The second controller voltage is equal to a sum of the third controller voltage and a second voltage difference.

Abstract: A semiconductor device for a switching power supply includes first and second external terminals, ON and OFF timing generation circuits, and a drive pulse generation circuit. To the first and second external terminals, a feedback voltage and a voltage induced in an auxiliary winding are input, respectively. The ON and OFF timing generation circuits respectively generate timing signals turning on and off a switching element based on the voltages. The drive pulse generation circuit generates a pulse signal based on these signals. The ON timing generation circuit includes: a bottom detection circuit detecting a lowest point of the voltage of the second external terminal; and a timer circuit, and operates in a PWM mode and a quasi-resonant mode in response to a timing of an output of the timer circuit being before a timing of an output of the bottom detection circuit and the reverse case, respectively.

Abstract: A power supply apparatus including a first circuit and a second circuit insulated from the first circuit includes an adjustment unit and a detector in the first circuit, a controller in the second circuit, and first and second communication units in the first and second circuits, respectively. The adjustment unit is configured to adjust power. The controller is configured to control the adjustment unit. The detector is configured to detect a parameter. The second communication unit is configured to perform wireless communication with the first communication unit. The first communication unit is operated with power supplied to the first communication unit by a signal generated in the first communication unit due to a signal output from the controller to the second communication unit, and transmits information about a result of detection by the detector to the second communication unit. The controller controls the adjustment unit based on the information.

Abstract: A method of dynamically adjusting a storage time of a bipolar junction transistor (BJT) in a switched mode power converter during a switching cycle includes generating a storage time reference signal responsive to an input voltage signal. A collector off signal is generated responsive to a comparison of a current sense signal to a collector off reference threshold signal. The current sense signal is representative of a switch current of the BJT. A base off reference threshold signal is generated responsive to the storage time reference signal and the collector off signal. A base off signal is generated responsive to a comparison of the current sense signal and the base off reference threshold signal. Charging of a base terminal of the BJT is discontinued responsive to the base off signal, and the base terminal of the BJT is discharged responsive to the collector off signal.

Abstract: An output voltage calibration circuit and technique is disclosed to increase the accuracy and precision of the constant-voltage mode for a flyback converter.

Abstract: A controller includes an oscillator coupled to a switch to determine a time at which the switch is turned on. The oscillator includes a capacitor, a charging current source and a discharging current source coupled to charge and discharge the capacitor. A time period for the capacitor to charge and discharge between first and second voltage levels is a time period of a switching cycle. A duty cycle mode control circuit is coupled to operate in a first duty control mode in response to a feedback signal being between first and second feedback signal values, operate in a second duty control mode in response to the feedback signal being a between the second and third feedback signal values, and operate in a third duty control mode in response to the feedback signal being between the third and fourth feedback signal values.

Abstract: Disclosed examples include isolated load switch driver circuits to drive a load, including an impedance circuit that receives a digital input voltage signal from a signal source, and selectively allows a current signal to flow from the signal source to charge a buffer capacitor. An impedance control circuit controls the impedance circuit to limit the current signal in response to the buffer capacitor reaching a first threshold voltage, and an output circuit provides an output isolated from the digital input voltage signal to switch the load. A signaling circuit selectively enables the output circuit to draw power from the buffer capacitor in response to the voltage of the buffer capacitor reaching the first threshold voltage.

Abstract: A switching power supply comprising: a control circuit which is provided at a primary side and controls a switching element based on a value which is fed back from a secondary side; a transformer; a secondary side rectifier element which rectifies voltage which is supplied from the transformer; and a secondary side smooth element which smoothes voltage which is rectified by the rectifier element, wherein voltage which is smoothed by the smooth element is supplied to an amplifier and voltage which is smoothed by the smooth element is fed back to the control circuit, further comprising: a diode which is connected between the smooth element and the amplifier in series.

Abstract: Systems and methods are provided for regulating power conversion systems. A system controller includes: a first controller terminal configured to receive a first signal related to an input signal for a primary winding of a power conversation system; and a second controller terminal configured to output a drive signal to a switch to affect a current flowing through the primary winding, the drive signal being associated with a switching period including an on-time period and an off-time period. The switch is closed (e.g., being turned on) in response to the drive signal during the on-time period. The switch is opened (e.g., being turned off) in response to the drive signal during the off-time period. A duty cycle is equal to a duration of the on-time period divided by a duration of the switching period. The system controller is configured to keep a multiplication product of the duty cycle and the duration of the on-time period approximately constant.

Abstract: A power supply apparatus including a first circuit and a second circuit insulated from the first circuit includes an adjustment unit and a detector in the first circuit, a controller in the second circuit, and first and second communication units in the first and second circuits, respectively. The adjustment unit is configured to adjust power. The controller is configured to control the adjustment unit. The detector is configured to detect a parameter. The second communication unit is configured to perform wireless communication with the first communication unit. The first communication unit is operated with power supplied to the first communication unit by a signal generated in the first communication unit due to a signal output from the controller to the second communication unit, and transmits information about a result of detection by the detector to the second communication unit. The controller controls the adjustment unit based on the information.

Abstract: Herein is disclosed an electronic converter, including a measurement circuit for determining a first signal indicative of the voltage or current supplied by the electronic converter, a regulation circuit for generating a regulation signal as a function of the first signal and one or more reference signals, and a driver circuit for driving the switching stage of the electronic converter as a function of the regulation signal.

Abstract: A testing system including an adapter and a testing circuit is provided. The adapter includes a converter having a first side and a second side, an inputting terminal and an outputting terminal. The testing circuit includes a testing switch having a first terminal and a second terminal, a detecting circuit and a first indicator. The first side is coupled to the inputting terminal. The second side is coupled to the outputting terminal. The converter is used to convert inputting power for providing outputting power to a load system. The first terminal is coupled to the outputting terminal. The detecting circuit is coupled to the second terminal. When the first terminal is couple with the outputting terminal and contacted with the second terminal, the detecting circuit is used to detect an outputting signal of converter for generating a detecting result. The first indicator sends a message according to the detecting result.

Abstract: When the temperature detected by the temperature sensor is equal to or higher than a predetermined temperature, the drive system controls the boost converter and the inverter, such that the motor is driven in a range of an electric power on which a limit is imposed to decrease a discharge power upper limit value. When a failure occurs in the boost converter, the drive system stops the boost converter. When it is subsequently determined that the failure of the boost converter causes a failure of the temperature sensor, the drive system controls the inverter, such that the motor is driven without a limit imposed on the discharge power upper limit value, irrespective of the temperature detected by the temperature sensor that is equal to or higher than the predetermined temperature.

Abstract: A power converter determines a feedback signal according to a voltage signal related to an output voltage of the power converter and a reference voltage, thereby regulating the output voltage. A control circuit and method for programming the output voltage of the power converter utilize an offset current generator to inject a current or sink a current for changing the voltage signal or the reference signal, thereby adjusting the output voltage. As a result, it gets rid of complicated circuitry but provides more steps adjustment, which reduces related costs.

Abstract: A method for controlling a power converter switch includes operating the power converter switch in first, second, and third duty cycle control modes in response to a feedback signal representative of an output of the power converter. The first duty cycle control mode includes modulating a peak switch current of the power converter switch in response to the feedback signal, and switching the power converter switch at a substantially fixed first switching frequency value. The second duty cycle control mode includes modulating the switching frequency in response to the feedback signal, and maintaining the peak switch current substantially at a peak switch current threshold value. The third duty cycle control mode includes modulating the peak switch current of the power converter switch in response to the feedback signal, and switching the power converter switch at a substantially fixed second switching frequency value.

Abstract: A method and apparatus for secondary side current mode control of a converter are provided. In the method and apparatus, an output voltage of the converter is detected, where the converter has primary and secondary windings that are galvanically isolated in respective primary and secondary sides. A secondary control signal is generated in the secondary side based at least in part on the output voltage and a reference voltage. The secondary control signal is converted to a primary control signal provided in the primary side. The converter is driven in the primary side based at least in part on the primary control signal and a current sense signal indicative of a current flowing through the primary winding.

Abstract: A controller for a power converter includes a driver circuit that generates a control signal to switch a power switch in response to an output, and a control circuit that controls the switching of the power switch. The control circuit includes a storage time reference circuit generates a storage time reference signal responsive to an input. A first comparator generates a collector off signal in response to a comparison of a switch current sense signal and a collector off reference signal. A storage time regulator circuit generates a base off reference signal in response to the storage time reference signal and the collector off signal. A second comparator generates a base off signal in response to a second comparison of the switch current sense signal and the base off reference signal. The driver circuit is coupled to discontinue and start charging a base terminal of the BJT power switch.

Abstract: Systems and methods are provided for regulating power conversion systems. A system controller includes: a first controller terminal configured to receive a first signal related to an input signal for a primary winding of a power conversation system; and a second controller terminal configured to output a drive signal to a switch to affect a current flowing through the primary winding, the drive signal being associated with a switching period including an on-time period and an off-time period. The switch is closed (e.g., being turned on) in response to the drive signal during the on-time period. The switch is opened (e.g., being turned off) in response to the drive signal during the off-time period. A duty cycle is equal to a duration of the on-time period divided by a duration of the switching period. The system controller is configured to keep a multiplication product of the duty cycle and the duration of the on-time period approximately constant.

Abstract: A variable-level flyback power converter is configured to provide an accurate output voltage at various regulation levels. The variable-level flyback power converter may include a switch coupled to a secondary winding of a transformer, a diode coupled to a primary winding of the transformer, and a controller coupled to the switch. The controller may scale an initial reference voltage based on a desired output voltage and a forward voltage drop across the diode, compare the scaled reference voltage with a feedback voltage sensed at an auxiliary winding of the transformer to generate an error signal, and modulate a pulse signal provided to the switch based on the error voltage.

Abstract: Disclosed is a voltage converter and a method. The voltage converter includes: an input, an output, and a transformer including a primary winding and a secondary winding; a primary side circuit comprising at least one switch and coupled between the input and the primary winding; a secondary side control circuit coupled to the output. The primary side circuit is configured to receive a feedback signal from the secondary side control circuit. The secondary side control circuit is configured to generate an error signal based on an output signal of the voltage converter, and to modulate the error signal based on supplemental information to generate the feedback signal.

Abstract: In a conventional current resonance switching power source, the burst period of a burst operation could not be sufficiently prolonged, and the efficiency characteristics were insufficient in a light load. In order to improve this, an embodiment of the present invention generates, upon operating in the burst mode, a control signal in accordance with a comparison result of a first reference voltage and a secondary side voltage of a transformer and a comparison result of a second reference voltage and the secondary side voltage of the transformer. Subsequently, the oscillation operation timing of an oscillator that performs an oscillation operation to the transformer and the oscillation frequency that changes the voltage excited on the secondary side of the transformer are controlled based on the control signal.

Abstract: A power supply apparatus and a method for controlling the power supply apparatus are provided. The power supply apparatus drives an electronic apparatus which may operate in a first mode or a second mode. The power supply includes an input voltage generator that generates an input voltage; an output voltage generator that generates a first output voltage by using the input voltage, and supplies the output voltage to the electronic apparatus; and a detector that determines the mode of the electronic apparatus by detecting a load of the electronic apparatus, and outputs a control signal to the output voltage generator in response to the mode of the electronic apparatus changing from the first mode to the second mode. In response to receiving the control signal, the output voltage generator generates a second output voltage that corresponds to the second mode.

Abstract: In some embodiments, a power system includes an integrated circuit (IC). The IC includes a first switching transistor having a load path coupled between a sensing terminal of the IC and a first terminal of the IC. The first terminal of the IC is configured to be coupled to a first load path terminal of a second switching transistor. The IC also includes a first diode coupled between the first terminal of the IC and a second terminal of the IC. The second terminal is configured to be coupled to an auxiliary winding of the power system. The IC further includes a first driver circuit having an output coupled to a third terminal of the IC. The third terminal is configured to be coupled to a control node of the second switching transistor.

Abstract: It is possible to achieve more precise power regulation in switched mode power supply systems by performing at least some control-loop processing on the secondary-side of the transformer. In particular, a secondary-side measurement is processed at least partially by a secondary-side controller to obtain a switching indication signal. The switching indication signal is then communicated from the secondary-side controller to a primary-side controller, where it is used to regulate the amount of energy applied to the primary winding. The switching indication signal may be any control signaling instruction that prompts the primary-side controller to regulate and/or modify the power applied to the primary winding. The switching indication signal may be communicated over an isolating signal path, such as a single-ended capacitive coupler, a differential capacitive coupler, an inductive coupler, or an opto-coupler.

Abstract: An electronic device including first and second line inputs, first and second device inputs, a filter circuit, and a switching circuit. The filter circuit has a first input electrically coupled to the first line input, a second input electrically coupled to the second line input, a first output electrically coupled to the first device input, a second output, and at least one capacitor electrically coupling at least one of the first input to the second input or the first output to the second output. The switching circuit has a control input to receive a control signal, and electrically couples the second output to the second device input in response to the control signal having the first state and electrically couples the second output to one of the first input and the first output through a resistor in response to the control signal having the second state.

Abstract: A device and system for converting a three phase power input to a direct current output, and method of operating the device and system, are provided. The device includes a rectifier circuit for rectifying the three phase power input into a plurality of rectified outputs, a converter circuit for converting each of the rectified outputs, and a control circuit for generating the control signal based at least in part on the single direct current output. Each of the rectified outputs may have a common first mean voltage level, which is converted to a second mean voltage level based on a control signal. Each of the rectified outputs at the second mean voltage level are capable of being combined into a single direct current output.

Abstract: A method and apparatus for converting DC input power to DC output power with reactive power control. The apparatus includes a plurality of flyback circuits, coupled in parallel, and a DC-AC inversion circuit coupled across an output of each flyback circuit of the plurality of flyback circuits. The apparatus also including a reactive power control circuit coupled to an output of one flyback circuit of the plurality of flyback circuits, and across an output of the DC-AC inversion circuit; and a controller operative to coordinate timing of switches in each flyback circuit of the plurality of flyback circuits and the reactive power control circuit to generate AC output power of a desired power factor.

Abstract: A method for controlling an output of a power converter includes switching a switching element with drive signals that are generated for switching a switching element during normal operation when an energy requirement of one or more loads at the output are above a low-load threshold. A non-regulated dormant mode of operation is entered when the flow of energy to the output is detected to be less than the low-load threshold value for more than a first period of time. The control circuit is powered down when in the non-regulated dormant mode of operation the control circuit is unresponsive to stop regulating the flow of energy to the output of the power converter. The control circuit remains in the non-regulated dormant mode of operation for a second period of time before powering up again to resume generating the drive signal and regulating the flow of energy.

Abstract: A control circuit can include: an output current sampling circuit configured to sample a current through a power switch of a switching power supply operating in a quasi-resonant mode, and to generate an output current feedback signal that represents an output current of the switching power supply; and a valley locking circuit configured to receive the output current feedback signal and a plurality of valley switching threshold voltages, where the valley locking circuit is switched to a corresponding valley from a valley currently being locked when the output current feedback signal is increased or reduced to one of the plurality of valley switching threshold voltages.

Abstract: Disclosed is an Auxiliary-Free High-Side Driven Secondary-Side Regulated (AF-HSD-SSR) flyback converter, which includes an AC-to-DC rectification unit, an input capacitor, a switching unit, a current-sensing resistor, an Auxiliary-Free (AF) flyback transformer, an output rectifier, an output capacitor, a PWM controller, and a SSR unit. The AF flyback transformer includes a primary winding and a secondary winding, where the primary winding is split into two halves. The switching unit is placed at the high side of the primary winding, and the PWM controller in collocation with the SSR unit drives the switching unit in response to all the required voltage and current sense signals to keep voltage conversion and power delivery safe and efficient within the specifications. The first half of the primary winding can provide the PWM controller with a continuous and steady working voltage supply after startup, thus eliminating the need for the auxiliary winding.

Abstract: A liquid crystal display apparatus is capable of reducing a power loss incurred by a power-supply section in a process of generating a power-supply voltage for driving a backlight section. In the configuration of the power-supply section, a main power-supply circuit and an inverter circuit (or a DC-DC converter) are connected to an input-voltage generation unit in parallel to each other, which is used for rectifying and smoothing the commercial alternative current power. The main power-supply circuit and the inverter circuit (or the DC-DC converter) each include an isolation transformer including a primary-side winding not isolated from the commercial alternative current power and a secondary winding provided on the secondary side. The direct current input voltage is supplied to the primary side to be subjected to a power conversion process to generate an output voltage on the secondary side of the isolation transformer.