Abstract: The present invention relates to an AC-DC power converter which includes a resonant DC-DC converter and a charge pump circuit. The charge pump circuit is configured to perform power factor correction of the AC-DC power converter by drawing current pulses at a switching frequency of the converter from an AC line voltage such that electrical charges of the current pulses vary substantially proportionally with instantaneous amplitude of the AC line voltage.

Abstract: A voltage converter includes a feedback controller, a primary-side controller, a secondary-side controller, a primary-side rectification-filtration circuit, a boost converter, and a voltage conversion circuit. The feedback controller receives a voltage demand signal from an output end to output a first feedback signal and a second feedback signal. The primary-side controller generates a boost control signal and a first switching control signal according to the first feedback signal. The secondary-side controller generates a second switching control signal according to the second feedback signal. The boost converter is configured to boost a DC voltage outputted by the primary-side rectification-filtration circuit into a first voltage according to the boost control signal. The operation mode of the voltage conversion circuit is switched between a half-bridge rectification mode and a full-bridge rectification mode according to the first and second switching control signals.

Abstract: An input redundant power supply circuit includes a power converter, a relay switch unit including a first relay circuit coupled to a first power source and a second relay circuit coupled to a second power source, a control unit configured to control the relay switch unit so that the power converter is supplied power by the first or second power source, a high capacity capacitor powered by the power converter and a step-up converter coupled between the power converter and the high capacity capacitor. The step-up converter maintains a voltage across the high capacity capacitor higher than a voltage of the first power source or a voltage of the second power source when the relay switch unit switches from one of the first power source and the second power source to the other of the first power source and the second power source.

Abstract: An isolated switched-mode power converter converts power from an input source into power for an output load. Power switches within a primary-side power stage control the amount of power input to the power converter and, ultimately, provided to the output load. A digital controller on the secondary side of the power converter generates signals to control the power switches. This controller also senses a rectified voltage on the secondary side of the power converter and uses this sensed voltage to detect fault conditions of the primary side. For example, the sensed rectified voltage is used to detect undervoltage or overvoltage conditions of the input power source of the power converter, or faulty power switches within the primary-side power stage.

Abstract: A transformer includes a magnetic core having multiple limbs. The transformer also includes a direct current (DC) bias winding wound around a specified one of the limbs. The transformer further includes a DC amplifier electrically connected to the DC bias winding. The DC amplifier is configured to receive a first signal associated with a load output current or voltage. The DC amplifier is also configured to determine an amount of a current for the DC bias winding based on the first signal. The DC amplifier is further configured to send the determined amount of current through the DC bias winding.

Abstract: The present invention discloses a method and an apparatus for controlling a flyback converter, the flyback converter including a main switch, a transformer, and an auxiliary switch. The method includes: obtaining a first voltage signal and a second voltage signal, the first voltage signal representing an input voltage of the flyback converter, and the second voltage signal representing an output voltage of the flyback converter; controlling turn-on of the auxiliary switch, wherein the turn-on time period of the auxiliary switch is determined according to the first voltage signal and the second voltage signal; and turning on the main switch at ZVS condition, wherein the main switch is turned on at the time delayed for a duration of a dead time after turning off of the auxiliary switch.

Abstract: An LED luminaire emergency driver comprises a rechargeable battery, a charger circuit, an LED driving circuit, and a charging and discharging control circuit. The LED luminaire emergency driver is intended to automatically supply a first supplied voltage to drive LED arrays in an event of a normal power failure. The LED driving circuit is configured to convert a terminal voltage from the rechargeable battery into the first supplied voltage when a line voltage from AC mains is unavailable. The charging and discharging control circuit comprises a relay switch and a transistor circuit assembly configured to sense a charging voltage, to control switching between normal power and an emergency power to operate the LED arrays, and to meet regulatory requirements without operational ambiguity and safety issues.

Abstract: An insulation-type switching power supply according to the present invention includes: a PWM control circuit that generates and outputs a PWM pulse and a PWM pulse respectively by alternately extracting pulses of a PWM control pulse signal at a field-effect transistor in a flyback converter circuit; a pulse transformer; a bidirectional excitation circuit that excites a primary winding of the pulse transformer in the forward direction using the PWM pulse and excites the primary winding of the pulse transformer in the reverse direction using the PWM pulse; and a switching circuit that generates a pulse signal by inverting a negative pulse of a pulse signal, induced in a secondary winding of the pulse transformer, to a positive pulse and switches the field-effect transistor by using the generated pulse signal.

Abstract: A power conversion circuit includes a switching circuit, a resonant circuit, a rectifying circuit, a controller and a transformer including a primary winding and a secondary winding. The resonant circuit is electrically coupled to the switching circuit and the primary winding. The rectifying circuit is electrically coupled to the secondary winding. The controller is electrically coupled to the switching circuit and the rectifying circuit and configured to selectively output one of a frequency modulation signal and a pulse width modulation signal as a second control signal according to a working frequency of a first control signal.

Abstract: One example includes a power control system. The power control system includes an activation controller that is powered via a first power voltage generated via a first power supply and is configured to provide an enable signal. The activation controller can assert the enable signal in response to an input activation signal to control activation of a second power supply. The second power supply can generate a second power voltage in response to the enable signal being asserted. The second power voltage can be provided to regulate power associated with ancillary electronic circuitry. The system also includes a deactivation controller that is powered via the second power voltage and is configured to generate a disable signal to de-assert the enable signal in response to one of a plurality of predetermined deactivation conditions.

Abstract: A vehicle includes main contactors powered via a low voltage bus and disposed electrically between a traction battery and a high voltage bus, and a controller. The controller, responsive to the contactors remaining open following activation of the low voltage bus and reported voltage values associated with the high voltage bus being less than a threshold, operates a horn of the vehicle.

Abstract: A lighting device includes a switch coupled to receive DC input, and driven on/off by received gate drive signals to provide current through a primary transformer winding. A large output capacitor is coupled across output terminals for receiving a load. An output circuit is coupled between a secondary transformer winding and the output capacitor, and includes a small buffer capacitor and a buffer diode. A feedback circuit compares a voltage across the buffer capacitor with a reference signal and provides a feedback control signal for regulating the switch and accordingly the device output to the load. An auxiliary power supply includes a tertiary transformer winding and powers the feedback circuit. By implementing the voltage across the buffer capacitor, the discharge time during a non-standard operating condition (e.g., no load) is small enough to enable continuous operation of the auxiliary power supply, the feedback circuit and the switch.

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 lamp driver for an LED lamp is provided, comprising a voltage input port for connecting the lamp driver to a power source, a relay that is switchable between an energized state and a de-energized state according to a pick-up voltage, and a relay controller circuit that connects the relay to the voltage input port and that is switchable between a conducting state and an non-conducting state according to a threshold voltage, wherein the pick-up voltage is smaller than the threshold voltage.

Abstract: One cable compensation circuit is connected to a shunt regulator to generate a feedback voltage corresponding to an output voltage of a power supply device. The cable compensation circuit controls cathode impedance of the shunt regulator according to the output current of the power supply device to compensate a voltage drop generated in a cable.

Abstract: A boost converter having an inductor having a first terminal coupled to an input port to receive the input voltage; a high side switch coupled between the inductor and an output port; a low side switch coupled between the inductor and a ground reference; and a control circuit configured to receive a feedback signal indicative of the output voltage and a reference signal, and to provide a high side control signal and a low side control signal based on the feedback signal and the reference signal; wherein the low side switch on time period is controlled to be constant by the low side control signal when the input voltage and the output voltage are fixed.

Abstract: A power supply includes a connector, a power conversion controller to generate a power supply signal at the connector, and a communication and control processor. The communication and control processor is to receive a set of current control parameters including a current limit over a communication link in the connector, receive measurements of current and voltage of the power supply signal, and generate a drive signal for controlling the power conversion controller based on the received current control parameters and the measurements of the current and the voltage.

Abstract: The present disclosure is directed to a high power factor quasi resonant converter. The converter converts an AC power line input to a DC output to power a load, generally a string of LEDs. The power input is fed into a transformer being controlled by a power switch. The power switch is driven by a controller having a shaping circuit. The shaping circuit uses a current generator, switched resistor and capacitor to produce a sinusoidal reference voltage signal. The controller drives the power switch based on the voltage reference signal, resulting in a sinusoidal input current in a primary winding of the transformer, resulting in high power factor and low total harmonic distortion for the converter.

Abstract: A power converter for converting input power to output power includes a first transformer circuit, a second transformer circuit, and balance circuitry. The first transformer circuit includes a first primary winding for receiving a first part of the input power and a first secondary winding for generating a first part of the output power. The second transformer circuit includes a second primary winding for receiving a second part of the input power and a second secondary winding for generating a second part of the output power. The balance circuitry is coupled to a first terminal of the first secondary winding and a second terminal of the second secondary winding, and operable for balancing the first and second parts of the output power by passing a signal between the first and second terminals. The first and second terminals have the same polarity.

Abstract: An external circuit element RSET is connected in use to an SET terminal. A synchronous rectification controller generates a pulse signal S1 based on a control time determined according to the state of the SET terminal. A driver switches on and off the synchronous rectification transistor according to the pulse signal S1. An abnormal state detection circuit is capable of detecting an open-circuit state and/or a short-circuit state that can occur in the SET terminal. When the abnormal state detection circuit detects such an open-circuit state and/or short-circuit state, the abnormal state detection circuit asserts a detection signal S11. When the detection signal S11 is asserted, a primary-side controller arranged on the primary side of the DC/DC converter is instructed to suspend the switching operation of a switching transistor.

Abstract: A combined voltage regulator and snubber circuit generally has a voltage regulator device in parallel with the energy storage element of the snubber circuit operatively connectable in series with a leakage inductance current path; the leakage inductance being part of a magnetic component utilized in a switch-mode power supply having an input voltage source, controllable semiconductor switches, freewheeling semiconductor switches, feedback controller, reactive energy storage components and a load; the voltage regulator generally providing constant or variable voltage to the gate driver of the controllable semiconductor and/or feedback controller.

Abstract: A circuit for generating an output current includes a control signal generating circuit that is configured to generate a control signal. The control signal is a function of a level of an analog input voltage signal, and a level of the output current is a function of a level of an analog input current signal and the level of the analog input voltage signal.

Abstract: A chopped current input electrical energy converter includes at least one conversion module (K1, K2) generating at least one first output signal (Vout1) and one second output signal (Vout2) and including: a transformer (10), an input switching stage (20) controlling the transfer of electrical energy to the transformer (10), and at least one first output stage (30) and one second output stage (40), the first output stage (30) generating the first output signal (Vout1), and the second output stage (40) generating the second output signal (Vout2); the level of the first output signal (Vout1) reflected at a primary winding (11) of the transformer (10) is greater than the level of the second output signal (Vout2) reflected at the primary winding (11) of the transformer (10).

Abstract: A method for controlling a power converter switch to regulate power delivered to an output of a power converter includes operating the power converter switch in first, second, and third duty cycle control modes in response to a feedback signal. 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 power supply includes a control transistor that controls a primary winding of a transformer to induce current on a secondary winding of the transformer to generate an output voltage. A pulse width modulation (PWM) controller integrated circuit (IC) chip drives the control transistor through a gate pin. The PWM controller IC chip has a feedback pin that receives a feedback signal indicative of the output voltage. A high voltage (HV) startup transistor is controlled through the feedback pin. The HV startup transistor turns ON during startup to generate a supply voltage from current received from the input voltage of the power supply. The HV startup transistor turns OFF when the supply voltage reaches a startup voltage level that is sufficient to start the switching operation of the control transistor and thereby receive operating current from an auxiliary winding of the transformer.

Abstract: A converter for converting an input-side alternating current into an output-side DC current, with a power factor correction being provided, wherein the converter comprises a transformer having at least two serially arranged primary windings, a first switch is used to switch a storage capacitor unit in series with a first primary winding to the alternating current in a clocked manner via rectification elements and a second primary winding is switchable to the storage capacitor unit in a clocked manner by a second switch.

Abstract: In one embodiment, a method of compensating for transmission voltage loss from a switching power supply, can include: (i) receiving a sampling signal that represents an output current of the switching power supply; (ii) delaying the sampling signal to generate a delayed sampling signal; (iii) converting the delayed sampling signal to generate a compensation signal; and (iv) regulating an output voltage of the switching power supply based on the compensation signal to compensate for the transmission voltage loss from the output voltage transmission to a load such that a voltage at the load is maintained as substantially consistent with an expected voltage at the load.

Abstract: In accordance with various embodiments a converter is provided, including: a transformer comprising a primary side and a secondary side; a primary side circuit arrangement coupled to the primary side of the transformer; a secondary side circuit arrangement coupled to the secondary side of the transformer, wherein the secondary side circuit arrangement is configured to provide at least one of an output voltage and an output current; a coupling component configured to provide information about at least one of the output voltage and the output current to the primary side circuit arrangement; a first energy supply configured to provide the coupling component with a first current; and second energy supply configured to provide the coupling component with a second current, wherein the second current is lower than the first current.

Abstract: This printed circuit board (12) comprising: a first portion (20) having first electronic components (22) of which the earth electrode is on a first voltage source (14); a second portion (24) having second electronic components (26) of which the earth electrode is on a second voltage source (16); a third portion (28) inserted between the first portion (20) and the second portion (24); a switched-mode power supply circuit (32) connecting the first portion (20) and the second portion (24); the said second portion (24) also comprising an electronic component (30) powered by the said first voltage source (14), is characterized in that it also comprises detection means (34) for detecting a drop in electrical consumption of the component (30) and switching means for switching the switched-mode power supply circuit (32) when a predetermined drop in electrical consumption of the said component (30) is detected.

Abstract: An electronic system includes a controller to provide at least dual-mode conduction control of a switching power converter. In at least one embodiment, the controller is capable to control transitions between discontinuous conduction mode (DCM) and critical conduction mode (CRM) of the switching power converter using a measured switching time parameter having a value corresponding with an approximately peak voltage of a time-varying supply voltage supplied to the switching power converter. In at least one embodiment, the controller dynamically compensates for changing parameters of the electronic system by dynamically determining a minimum non-conductive time of the control switch of the switching power converter using the measured switching time parameter value at approximately the peak of the supply voltage of the supply voltage.

Abstract: An electrostatic discharge clamp may include a reference generator and a comparator. The electrostatic discharge clamp may be characterized by a time constant. A voltage difference caused by an electrostatic discharge event may activate the electrostatic discharge clamp. The comparator may hold the electrostatic discharge clamp in an active state responsive to a reference voltage provided by the reference generator. A duration of the active state of the electrostatic discharge clamp may facilitate dissipation of the electrostatic discharge event.

Abstract: An isolator includes: a transmission circuit that generates an alternating current transmission signal in which a first potential is set to be a reference potential; a first insulating element to which the alternating current transmission signal is supplied; a second insulating element that generates an alternating current reception signal in which a second potential is set to be a reference potential by being alternating current-coupled to the first insulating element through an insulating film; a reception circuit that reproduces reception data based on the alternating current reception signal; an impedance control unit that controls an impedance of the first or the second insulating element to be higher than an impedance before the control; and a leakage current detection unit that detects a leakage current flowing between the first and the second insulating elements through the first or the second insulating element in which the impedance has been controlled.

Abstract: The present invention discloses a flyback power supply circuit with a programmable function and a control method thereof. The flyback power supply circuit includes: a transformer circuit, a power switch circuit, a primary side control circuit, an opto-coupler circuit, and a secondary side control circuit. The primary side control circuit determines whether an over voltage condition occurs, and further determines whether to generate an over voltage protection signal to turn OFF a power switch of the power switch circuit according to a rate of increase of a feedback signal and a control level, or according to the rate of increase of the feedback signal and a rate of change of a target control signal.

Abstract: A controller for use in a power converter includes an oscillator that generates a first signal that determines a duration of a switching cycle period of a switch included in the power converter. The controller also includes a logic circuit that generates a second signal to control switching of the switch in response to a feedback signal and in response to the first signal. The logic circuit generates the second signal to control a peak switch current of the switch during each switching cycle period according to either a first mode of operation or a second mode of operation. The peak switch current of the switch is varied in the first mode of operation in response to the feedback signal indicating that an output load is greater than a threshold and the peak switch current of the switch is kept at a constant value in the second mode of operation in response to the feedback signal indicating that the output load is less than the threshold.

Abstract: A power supply device having a standby power cutoff structure, comprises: a power supply unit which has a plug connected to a socket, converts an external power for a power supply target device, and generates self-operating power; a connector unit which includes a power supply terminal to supply power to the power supply target device, and opens or blocks a power supply path between the external power and the power supply unit in response to a switching driving signal received from the power supply unit; and a cable for connecting the power supply unit and the connector unit, wherein the power supply unit checks the state of power supplied through a switching unit to output the switching driving signal to the switching unit such that the switching unit cuts off a power supply when the power supply target device is fully charged or the power supply device is turned off.

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 display apparatus, a power supply apparatus and a power supply method are provided. The display apparatus display apparatus includes: a signal receiving unit which receives an image signal; a signal processing unit which processes the image signal; a display unit which displays an image based on the image signal processed by the signal processing unit; and a power supply unit which receives AC power and supplies operation power to the display unit. The power supply unit includes a discharging circuit part which includes a discharging element which discharges the power supply unit to remove a residual voltage from the power supply unit when the AC power is suspended, the discharging circuit part preventing the discharging element from consuming power when the AC power is input. It is possible to minimize wasteful power consumption caused by a discharging element provided to guarantee user's safety against a residual voltage.

Abstract: A power converter controller includes a drive signal generator coupled to generate a drive signal to control switching of a power switch to regulate a flow of energy to a power converter output in response to an energy requirement of a load. A voltage supply rail is coupled to supply a voltage to the drive signal generator. The supplied voltage is used by the drive signal generator to generate the drive signal. A control circuit is coupled to generate a power down signal that stops the supply of the voltage to the drive signal generator to stop the generation of the drive signal and the control of the switching of the power switch for a period of time. Timer circuitry determines a duration of the period of time and triggers the control circuit to restart the supply of the voltage by the supply rail to the drive signal generator.

Abstract: A controller includes a PWM circuit and a timing circuit. The PWM circuit controls a switch in response to a clock signal. A switching period of the clock signal is based on a charging and discharging time of a capacitor included in the timing circuit. Both first and second current sinks discharge the capacitor while the timing circuit is in a normal discharging mode that is when an on time of the switch is less than a threshold time. The second current sink is prevented from discharging the capacitor such that the capacitor is discharged with the first current sink and not the second current sink while the timing circuit is in an alternative discharging mode that is when the on time of the switch exceeds the threshold time. The discharging of the capacitor in the alternative discharging mode increases the switching period of the clock signal.

Abstract: Embodiments include systems and methods of powering data communications transmitter circuitry using current sinked from biasing circuitry used to bias a transmission line between the data communications transmitter circuitry and data communications receiver circuitry. In some embodiments, the current sinked from the biasing circuitry is sourced by a power supply configured to power the data communications receiver circuitry. The current sinked from the biasing circuitry is then re-used to power the data communications transmitter circuitry. The data communications transmitter circuitry may be operated using less power overall by re-using the current first used to bias the transmission line to power the data communications transmitter circuitry. Various embodiments include HDMI transceivers, DVI transceivers, and DisplayPort transceivers.

Abstract: A power supply apparatus includes a converter to convert AC power into DC power, an SMPS to convert the DC power into DC powers desired by loads, a capacitor to interconnect the converter and the SMPS, a PTC element connected to the converter, a first switch connected in parallel with the PTC element, and a second switch connected in series with the first switch. The method includes turning on the second switch to start charging of the capacitor, turning on the first switch to charge the capacitor to a target voltage level, and turning off both the first switch and second switch if a voltage across the capacitor rises over the target voltage level, to discharge the voltage across the capacitor so as to lower the voltage across the capacitor to the target voltage level or lower.

Abstract: An electronic system includes a controller to provide at least dual-mode conduction control of a switching power converter. In at least one embodiment, the controller is capable to control transitions between discontinuous conduction mode (DCM) and critical conduction mode (CRM) of the switching power converter using a measured switching time parameter having a value corresponding with an approximately peak voltage of a time-varying supply voltage supplied to the switching power converter. In at least one embodiment, the controller dynamically compensates for changing parameters of the electronic system by dynamically determining a minimum non-conductive time of the control switch of the switching power converter using the measured switching time parameter value at approximately the peak of the supply voltage of the supply voltage.

Abstract: A power supply applied to an electronic device for providing power includes a transformer unit, a connector, a pulse-width modulation (PWM) control unit, and a switch unit. The connector is electrically connected with the secondary side of the transformer unit for outputting a first output voltage. The PWM control unit outputs a pulse signal with a first period. The switch unit is electrically connected between the PWM control unit and the primary side of the transformer unit. When the electronic device is connected to the power supply, the connector receives an external control signal, and the PWM control unit adjusts the pulse width of the pulse signal to a second period and transmits the pulse signal with the second period to the switch unit to control the connector to output a second output voltage to the electronic device.

Abstract: A system for sensing voltage in an isolated converter includes an input circuit isolated from an output circuit using a first transformer, the first transformer having a primary coil and a secondary coil, wherein the output circuit includes an output inductor and an output capacitor, and wherein the input circuit includes a power source that provides power to the output circuit through the first transformer; a feedback winding coupled to the output inductor to form a second transformer; and a monitor circuit that calculates a voltage across the output capacitor using a voltage across the feedback winding, a voltage across the primary coil of the first transformer, a turns ratio of the first transformer, and a turns ratio of the second transformer in order to provide feedback to control the input circuit.

Abstract: An interleaved forward voltage converter having a first inverter stage has a first transformer having a first secondary winding coupled to a filter inductor. A second converter stage has a second transformer having a second secondary winding coupled to the filter inductor. A diode is coupled between the first and second secondary windings to automatically connect the first and second secondary windings in series when a duty cycle of the converter exceeds 50%. An interleaved forward voltage converter can connect the two primary windings in either parallel or a series configuration. The two secondary windings can be connected in either parallel or a series configuration. Having the two primary windings in parallel and the two secondary windings in series allows the converter to operate with a lower input voltage. Having the two primary windings in series and the two secondary windings in a parallel configuration allows the converter to operate with a higher input voltage.

Abstract: An AC to DC converter system is disclosed in which a conversion circuit for converting an AC input signal to a DC output signal is operably coupled with a communication circuit designed for sensing output indicative of the presence or absence of a load at the DC output. The system is designed so that the conversion circuit operates in an inactive standby state when there is no load, and in an active state for supplying DC power when a load is present. The system is configured to operate using ultra-low power.

Abstract: A converter may include a transformer; a first circuit arrangement coupled to a first transformer side; a second circuit arrangement coupled to a second transformer side, wherein the second circuit arrangement is configured to provide an output voltage; a first coupler configured to provide information about the output voltage to the first circuit arrangement; wherein the first circuit arrangement is configured to determine a state of the secondary side based on the received information about the output voltage, and to generate a switch control signal dependent on the determined state; a switch circuit arranged on the second side; and a second coupler configured to provide a switch control signal from the first circuit arrangement to the switch circuit; wherein the switch circuit is coupled to the first circuit arrangement to provide a first circuit arrangement control signal to the first circuit arrangement depending on the switch control signal.

Abstract: The invention relates to a signal (feed) separator for dead-zero or live-zero measurement signals. The signal (feed) separator has a primary-side (feed) input, a secondary-side output, a direct-current transformer for transferring primary-side measurement input current, an output stage for providing a secondary-side measurement output current, and an auxiliary energy feed-in for supplying the primary side and for supplying the secondary side. The auxiliary voltage of the auxiliary energy feed-in is controlled on the secondary side by a control device with the aid of a measuring device in such a way that the power loss of the output stage is substantially independent of a load connected in the operating state.

Abstract: The present invention relates to a power converter (90) and a method of operating same. There are numerous advantages to operating power converters using a series resonant converter (1, 21). This approach is particularly suitable for minimizing switching losses in the power converter when it is operated at high frequency. However, there are problems with the known converters in that they are prone to generate noise in the acoustic spectrum due to the fact that the converter stages are often operating at different frequencies. The present invention relates to a power converter and a method of operating same that enables the operating frequency of the converter to be controlled by a control circuit over a predetermined range of the resonant frequency. This allows reduction in acoustic noise generation and facilitates frequency smearing that will in turn reduce spectral peaks. This is achieved while maintaining output ripple within acceptable ranges.

Abstract: A switching power supply circuit (101) includes a first rectifier circuit (102) converting an alternate current to a direct current, a switching operator (20), a switching transformer (103) including a primary coil supplied with a switched current and a secondary coil inducing power corresponding to the current, a second rectifier circuit (30) rectifying the power induced by the secondary coil, and a control circuit (40) changing a ratio of a current flowing to a photocoupler (107) to an output voltage from the second rectifier circuit (30) in a standby mode and in a power-on mode to reduce a noise of the switching transformer in each of the modes.