Abstract: A control device for a resonant converter, the control device including a first circuit to integrate at least one signal indicating a half wave of a current circulating in a primary winding of a transformer; the first circuit is structured to generate at least a control signal of the switching circuit depending on the integrated signal. The control device includes a second circuit to impose the equality of a switching-on time period of the first and second switches.

Abstract: An apparatus and system for power conversion. In one embodiment, the apparatus comprises a transformer having a primary winding and a plurality of secondary windings comprising a first secondary winding, a second secondary winding, and a third secondary winding, the first, the second, and the third secondary windings wound in a tri-filar configuration; and a cyclo-converter comprising a plurality of switch pairs for converting an alternating current to an AC current, each switch pair in the plurality of switch pairs coupled between two lines of an AC output and having a different secondary winding of the plurality of secondary windings coupled between its switches, the plurality of switch pairs comprising a first switch pair, a second switch pair, and a third switch pair, wherein the first, the second, and the third secondary windings are coupled between drain terminals of the first, the second, and the third switch pair, respectively.

Abstract: A DC-DC converter is configured with a step-down converter that outputs a output voltage having the same voltage value as an input voltage when a step-down operation stops and that outputs the first output voltage having a lower voltage value than the input voltage when the step-down operation is performed, and a resonant converter in which a voltage transfer factor is adjusted by a switching frequency of a switching element through which a resonance current flows. A step-down operation of the step-down converter is performed when the switching frequency, the voltage transfer factor and a target value for the output voltage satisfy a predetermined condition. According to the above configuration, it is possible to decrease switching loss of the step-down converter.

Abstract: A converter supplies output power according to a first output current and a second output current generated according to each switching operation of a first switch and a second switch. A duty adjuster circuit generates an adjuster current to compensate the difference between the peak of the first output current and the peak of the second output current to adjust duty of the first and second switches.

Abstract: A power converter includes an input stage connected to receive a three phase AC input voltage and to provide multiple DC voltage levels. The power converter also includes an output stage of a plurality of interleaved LLC converters having series-connected inputs coupled to the multiple DC voltage levels and parallel-connected outputs to provide a DC output voltage. Additionally, the power converter includes a balancing circuit interconnected to the input and output stages to provide substantially balanced output currents from the plurality of interleaved LLC converters for the DC output voltage. Methods of manufacturing and operating a power converter are also provided.

Abstract: A switched mode power converter includes a closed loop feedback control mechanism for regulating an output characteristic and a resonant type circuit for inclusion of resonant energy delivery. The characteristic impedance of the resonant type circuit is modified from an optimal energy transfer configuration to one that dampens fluctuations in a feedback signal used by the closed loop feedback mechanism. The modified characteristic impedance functions to dampen those fluctuations in the feedback signal resulting from leakage inductance energy provided by the resonant type circuit.

Abstract: Disclosed is a bidirectional DC/DC converter including: a primary side circuit that includes a first DC power source or a first load; a secondary side circuit that includes a second load or a second DC power source; and a power transfer unit that is capable of transferring power bi-directionally between the primary side circuit and the secondary side circuit. Further, the bidirectional DC/DC converter includes a control circuit that controls the primary side circuit and secondary side circuit in such a way that current flows through the power transfer unit from the first DC power source to the second load or from the second DC power source to the first load.

Abstract: A method and apparatus for conversion of high voltage AC to low voltage high current DC without using high voltage capacitors or transformers. A single switch is used to perform both the functions of pre-regulation and switching conversion. An input voltage detector determines when the input power AC is below a predetermined voltage limit. A threshold voltage generator provides a threshold voltage corresponding to the output voltage. A voltage comparator coupled to the input voltage detector and threshold voltage generator enables a pulse generator to activate the switch to gate a number of pulses of the input power below the predetermined voltage limit at predetermined frequency to a transformer. The converter regulates its output voltage by changing the input voltage threshold at which it starts switching, instead of using PWM or other known regulation technique.

Abstract: A control device for a switching circuit of a resonant converter having a direct current at the output, the switching circuit having at least one half bridge of at least first and second transistors connected between an input voltage and a reference voltage. The half bridge is adapted to generate a periodic square wave voltage to drive the resonant circuit of the resonant converter; The control device has a circuit to proportionally generate a first voltage to a switching period, and a circuit adapted to limit the voltage at the ends of a capacitor between a reference voltage and the first voltage, and a further circuit structured to control the switching off of a first or second transistor at the time instant in which the voltage across the capacitor has reached the first voltage.

Abstract: A power converting device includes a switching unit, a resonant unit, a converting unit, a rectifying and filtering unit, an inductance-sensing unit, and a driver. The resonant unit is electrically connected to the switching unit and includes a resonant capacitor, a resonant inductor, and a variable magnetizing-inductor having at least two inductances, the resonant inductor is electrically connected to the resonant capacitor and the variable magnetizing-inductor. The converting unit is electrically connected to the resonant unit. The rectifying and filtering unit is electrically connected to the converting unit. The inductance-sensing unit is electrically connected to the rectifying and filtering unit, the inductance-sensing unit instantaneously senses inductances of the variable magnetizing-inductor.

Abstract: The configurations of a resonant converter system and a controlling method thereof are provided. The proposed resonant converter system includes a resonant converter and a hybrid control apparatus coupled to the resonant converter for generating a driving signal to adjust a phase angle and a frequency of the resonant converter such that the resonant converter would reach a relatively lower voltage gain and have a relatively lower loss during an abnormal operation.

Abstract: An integrated circuit includes a first pin for receiving a feedback signal, a second pin for receiving a current signal indicative of a current in a primary of a transformer, and a switching circuit coupled to the first and second pins and responsive to the feedback signal to determine a frequency at which to provide an upper drive signal and a lower drive signal, and further responsive to the current signal to change a value of the feedback signal when the current signal exceeds a first threshold, and to stop providing the upper and lower drive signals when the current signal exceeds a second threshold, the second threshold higher than the first threshold.

Abstract: A direct current to direct current (DC/DC) converter includes a resonant converter stage, a buck stage, and a processor apparatus. The resonant converter stage includes a bridge circuit. The buck stage is configured to output an output voltage and an output current, is electrically connected in series with the resonant converter stage, and includes a buck switch. The processor apparatus is configured to sense the output voltage and the output current, and, based on the sensed output voltage and the sensed output current, to perform one of: (a) fixing a switching frequency of the bridge circuit to a predetermined maximum switching frequency and controlling the output voltage by controlling a duty cycle of the buck switch, and (b) fixing the duty cycle of the buck switch to a predetermined duty cycle and controlling the output voltage by controlling the switching frequency of the bridge circuit.

Abstract: The disclosed embodiments provide an AC/DC power converter that converts an AC input voltage into a DC output voltage. This AC/DC power converter includes an input rectifier stage which rectifies an AC input voltage into a first rectified voltage. The AC/DC power converter also includes a switching resonant stage which is directly coupled to the output of the input rectifier stage. The switching resonant stage converts the rectified voltage into a first high frequency AC voltage of a first amplitude. This AC/DC power converter additionally includes a transformer which is coupled to the output of the switching resonant stage and is configured to down-convert the first high frequency AC voltage into a second high frequency AC voltage of a second amplitude. Furthermore, the AC/DC power converter includes an output rectifier stage which is coupled to the output of the transformer, wherein the output rectifier stage rectifies the second high frequency AC voltage into a DC output voltage.

Abstract: There is provided a power supply apparatus capable of precisely control a primary side switching frequency at a secondary side by receiving fed-back information regarding a power state at the secondary side without a separate expensive circuit or a complicated circuit. The power supply apparatus includes: a power supplying unit having a primary side and a secondary side having different ground electrical characteristics, switching power input to the primary side, and transferring the switched power to the second side electrically insulated from the primary side to supply the power; a controlling unit provided on the secondary side and receiving fed-back information regarding a power state of the power supplying unit to control a maximum value and a minimum value of a switching frequency of the primary side; and a transferring unit transferring a control signal from the controlling unit to the primary side of the power supplying unit.

Abstract: There is provided a multi-output power supply apparatus capable of maintaining multiple output voltages in a balanced state by limiting a variable range of a switching duty according to a load state. The multi-output power supply apparatus includes: a power supply unit switching input power to output a plurality of voltages whose power levels are determined according to the switching operation; and a controller detecting power states of at least some of the plurality of voltages from the power supply unit, and limiting a range of a switching duty of the power supply unit to a pre-set range when the detected power states correspond to a pre-set limited power state.

Abstract: A control circuit of a DC/DC converter having a transformer, a switching transistor, and a detector includes: a feedback terminal receiving a feedback voltage corresponding to an output voltage of the DC/DC converter; a current detection terminal receiving a detection voltage generated in the detection resistor; a conversion circuit configured to amplify, attenuate and/or level-shift at least one of the feedback voltage and the detection voltage, wherein a gain and/or a shift of the conversion circuit are variable; and a gain controller configured to control the gain and/or the shift of the conversion circuit.

Abstract: A gate driving circuit includes a driving stage configured to receive an input signal and generate a gate drive signal for a gate of a transistor switch. The gate driving circuit also includes an LC circuit having an inductor and a gate capacitance of the transistor switch. The LC circuit is configured so that a pulse in the gate drive signal generates a ringing in the LC circuit at a resonance frequency of the LC circuit to transfer energy into and out of the gate capacitance of the transistor switch. A switch could selectively couple the gate of the transistor switch to ground in order to discharge the gate capacitance. A control circuit could be used to provide the input signal, and the control circuit could be configured to regulate a duty cycle of the gate drive signal by adjusting an off-time between consecutive pulses in the input signal.

Abstract: In a switching power supply apparatus, a first switching element is controlled by a driving voltage output from a switching control IC. A second switching control circuit controls the on-time of a second switching element so that the time ratio of the on-time of the second switching element to the on-time of the first switching element becomes almost constant with respect to a change in a load current. In a normal load state, since a square wave output from a frequency setting unit within the switching control IC is output with no change, a converter operates in a current-continuous mode. In a light load state, a driving signal generation unit within the switching control IC is subjected to blanking with the period of a signal output from a maximum frequency setting unit and an oscillation frequency is reduced. Accordingly, the converter operates in a current-discontinuous mode.

Abstract: The present invention relates to a double-output half-bridge LLC serial resonant converter, comprising: a half-bridge rectifying unit, a first resonant unit, a first transformer unit, a first rectifying unit, a first output unit, a second resonant unit, a second transformer unit, a second rectifying unit, a second output unit, a voltage dividing unit, a voltage regulating unit, a light-coupling isolation unit, and a control unit. In the present invention, the double-output half-bridge LLC serial resonant converter has an inventive circuit framework, which can not only solve the unbalance load current and the output voltage cross regulation occurred in the conventional double-output convertor, but also normally modulate the no-load or light-load output voltage; therefore the output voltage deviation can be effectively controlled.

Abstract: The power converter is an integration of three topologies which include a forward converter topology, a flyback converter topology, and a resonant circuit topology. The combination of these three topologies functions to transfer energy using three different modes. A first mode, or forward mode, is a forward energy transfer that forwards energy from the input supply to the output load in a manner similar to a forward converter. A second mode, or flyback mode, stores and releases energy in a manner similar to a flyback converter. A third mode, or resonant mode, stores and releases energy from the resonant tank using a resonant circuit and a secondary side forward-type converter topologies.

Abstract: A dual gate drive circuit for a power converter and a control method are provided for reducing EMI of the power converter. The dual gate drive circuit comprises a switch and a switching control circuit. The switch is coupled to a transformer of the power converter to switch the transformer for regulating an output of the power converter. The switching control circuit generates a first switching signal and a second switching signal in response to a feedback signal to switch the switch for switching the transformer. The feedback signal is correlated to the output of the power converter. The second switching signal is enabled after a time delay once the first switching signal is enabled.

Abstract: A resonant capacitor and an inductor are connected in series between a primary winding of a transformer and a second switching element. A first rectifying and smoothing circuit including a first rectifier switching element and a capacitor rectifies and smoothes a voltage generated in a first secondary winding of the transformer, and takes out a first output voltage. A second rectifying and smoothing circuit including a second rectifier switching element and a capacitor rectifies and smoothes a voltage generated in a second secondary winding of the transformer, and takes out a second output voltage. A control circuit controls an on-time of a first switching element and an on-time of the second switching element in accordance with the first output voltage and the second output voltage, respectively.

Abstract: A control device controls a switching circuit of a resonant converter having an output direct current. The switching circuit includes at least a half-bridge of at least a first and a second transistor connected between an input voltage and a reference voltage. The half-bridge is adapted to generate a periodic square-wave voltage for driving the resonant circuit of said resonant circuit and the periodic square-wave voltage oscillates between a high voltage corresponding to the input voltage and a low voltage corresponding to the reference voltage. The control device comprises a generator adapted to generate a periodic square-wave signal for driving the half-bridge. The control device comprises a detector adapted to detect the phase-shift between the periodic square-wave signal generated by the generating means and the current flowing through the resonant circuit, and adapted to control the turning off of the half-bridge when the phase-shift exceeds a first phase-shift value.

Abstract: The present invention provides a controller for a power converter. The controller comprises a PWM circuit, a detection circuit, a signal generator, an oscillation circuit, a valley-lock circuit, a timing circuit and a burst circuit. The PWM circuit generates a switching signal coupled to switch a transformer of the power converter. A feedback signal is coupled to control and disable the switching signal. The detection circuit is coupled to the transformer via a resistor for generating a valley signal in response to a waveform obtained from the transformer. The signal generator is coupled to receive the feedback signal and the valley signal for generating an enabling signal. The oscillation circuit generates a maximum frequency signal. The maximum frequency signal associates with the enabling signal to generate a turning-on signal. The turning-on signal is coupled to enable the switching signal. A maximum frequency of the turning-on signal is limited.

Abstract: In controlling switching elements of a current source inverter, a switching loss in the switching element is prevented according to a normal switching operation for a commutation operation, without requiring any particular control. In the commutation operation of the current source inverter, a timing for driving the switching elements is controlled in such a manner that an overlap period is generated, during when both a switching element at the commutation source and a switching element at the commutation target are set to be the ON state, a resonant circuit is controlled based on the control of the switching elements having this overlap period, and resonant current of the resonant circuit reduces the switching loss upon commutation operation of the switching elements.

Abstract: A resonant-mode power supply, comprising an assembly of switches connected in a bridge or a half-bridge configuration, a series resonant circuit connected in the bridge or half bridge diagonal, a part of which is formed by a multi-winding inductor by means of which a load is connected, and a controller configured to stabilize output voltages or currents by controlling the switching frequency of the assembly of switches. The series resonant circuit comprises an energy recirculation circuit (ERC1) for limiting the resonant circuit quality factor, connected through the diode rectifier (DR2) to the supply voltage node and a current monitoring circuit (CMC) configured to monitor the recirculation circuit current (Ilim) and, by means of the controller (C), to change the switching frequency of the assembly of switches (K1, K2, K3, K4) in order to reduce power supplied to the resonant circuit upon exceeding the threshold value by the current (Ilim) in the energy recirculation circuit (ERC1).

Abstract: In a power supply apparatus driving circuit, at startup, an input voltage of a switching power supply is used as a driving power supply, and loss generated in a starting circuit is reduced. The starting circuit and the driving circuit are configured as a single driver. A control IC generates a switching control signal to control a first switching element and a second switching element. A driving circuit in a high breakdown voltage driver IC generates gate drive voltage signals for the first switching element and the second switching element based on the switching control signal inputted from the control IC. A starting circuit supplies the partial voltage of a voltage inputted to a starting power supply terminal, to each of the driving circuit in the high breakdown voltage driver IC and the control IC that is externally provided, and shuts off a switching element after startup.

Abstract: A power-supply unit including a transformer, a full bridge circuit having four arm switches on a primary side of the transformer, a rectifier and smoothing circuit including two synchronous rectifier switches on a secondary side of the transformer, a choke coil, and a capacitor, an output terminal in the rectifier and smoothing circuit, a control circuit controlling ON/OFF of the four arm switches of the full bridge circuit and the two synchronous rectifier switches of the rectifier and smoothing circuit, a resonant inductor including a leakage inductor component and a parasitic inductor component on the primary side of the transformer, and a resonant capacitor, and in which the control circuit includes a timing variable unit which varies switching timings of the two synchronous rectifier switches of the rectifier and smoothing circuit based on an output current flowing in the output terminal provided in the rectifier and smoothing circuit.

Abstract: A switching power source apparatus has a pulse generator of a first pulse. A first resonant series circuit receives the first pulse signal and passes a current having a 90-degree phase delay with respect to the first pulse signal. The current of the first resonant series circuit turns on/off a switching element Q21. A second resonant series circuit receives the second pulse signal and passes a current having a 90-degree phase delay with respect to the second pulse signal. The current of the second resonant series circuit turns on/off a switching element Q22. The pulse generator has a third transformer T3 that has secondary windings to output the first and second pulse signals according to a voltage that is applied to the third transformer and is synchronized with drive signals for the switching elements Q11 and Q12.

Abstract: The present invention provides a control circuit of an LLC resonant converter including a minimum switching frequency variable circuit of varying a minimum switching frequency corresponding to an AC input voltage of the LLC resonant converter; and a first pulse signal generating unit and a second pulse signal generating unit to generate a first pulse signal and a second pulse signal based on a switching frequency limited by the minimum switching frequency variable circuit.

Abstract: An LLC resonant power regulator system includes a transformer having a primary inductor and a secondary inductor and an input resonant tank including an input resonant capacitor, an input leakage inductor, and the primary inductor connected in series. The system also includes an input stage having a plurality of switches that are controlled in response to a respective plurality of switching signals sweeping frequency to supply an input resonant current to the input resonant tank. Each of the respective plurality of switching signals can have a fixed duty cycle and a sweeping frequency. The system further includes an output resonant tank that includes an output resonant capacitor, an output leakage inductor, and the secondary inductor connected in series. The output resonant tank can be configured to generate an oscillating output resonant current at an output.

Abstract: A method for controlling a direct current gain of a resonant converter to increase power efficiency within a circuit. A phase shift module is configured to the resonant converter for generating a first control signal to control a primary driver of the resonant converter and a secondary control signal to control a secondary driver of the resonant converter. The first control signal and the secondary control signal have a phase shift for controlling a DC gain of the resonant converter.

Abstract: A switching power supply determines the order n (a natural number) of the power supply higher harmonic component near the receiving frequency fc of an AM radio broadcast, and judges whether the higher harmonic component of the order n is higher or lower than the receiving frequency fc of the AM radio broadcast. According to the judgment result, the switching power supply determines an upper limit value and a lower limit value for the power supply frequency fs that does not interfere with the receiving frequency fc of the AM radio broadcast from the values of the fundamental power supply frequency fso of the switching operation, the order n of the higher harmonic component, the receiving frequency fc of the AM radio broadcast, and the bandwidth BW of the receiving frequency. The power supply frequency fs is set within the range specified by the upper and lower limit values.

Abstract: In one embodiment, a power supply controller is configured to adjust a peak value of a primary current through a power switch responsively to a difference between a demagnetization time and a discharge time of the parasitic leakage inductance of a transformer.

Abstract: A resonant conversion system is provided, in which a resonant converter receives an input voltage to generate an output voltage, and a buck converter provides the input voltage of the resonant converter, and controls the input voltage to perform an over-current protection process.

Abstract: A resonant DC converter, combines a voltage type auto charge pump circuit with a full-bridge or half-bridge resonant DC conversion circuit at a primary side of a transformer, combines a double-voltage rectifier circuit at a secondary side of the transformer, and grants the circuit of the invention with characteristics of variable circuit architecture by means of the design of circuit parameters and the action of the LC resonant circuit. Integration of switching elements of the converter circuit and the use of characteristics of automatically changing the circuit architecture contribute to reduce the switching losses and increase the circuit conversion efficiency. Low output voltage ripple enables the circuit of the invention to avoid using large-capacitance electrolytic capacitors and be able to extend the service life of the transformer. The operation of the circuit of the invention at boost or buck mode can be controlled by adjusting the circuit parameters.

Abstract: A system includes a load and a single-ended primary-inductance converter (SEPIC) power converter configured to provide power to the load. The SEPIC power converter includes a primary side and a secondary side that are electrically isolated by a transformer. The transformer includes a primary coil and a secondary coil. The primary side includes (i) a capacitor coupled to a first end of the primary coil and (ii) an inductor and a switch coupled to a second end of the primary coil. The primary side of the SEPIC power converter could also include a diode coupled between the inductor and the switch, where the diode is coupled to the second end of the primary coil. The capacitor could be configured to transfer energy to the secondary side of the SEPIC power converter through the transformer during valleys associated with a rectified input voltage.

Abstract: An off line resonant converter includes a boost storage inductance circuit coupled to a switcher circuit that includes stacked first and second passive switching devices coupled to the boost storage inductance circuit and stacked first and second active bidirectional switching devices coupled to the stacked first and second passive switching devices. The stacked first and second active bidirectional switching devices generate a square wave signal and alternately store energy in and receive energy from the boost storage inductance circuit such that a pulsating current is conducted between the boost storage inductance circuit and the switcher circuit. The pulsating current is bidirectional and flows in a direction responsive to a polarity of the ac input line voltage. A resonant circuit is coupled to an output of the switcher circuit to receive the square wave signal from the switcher circuit to generate an output of the resonant converter.

Abstract: An isolated interleaved DC converter has a main circuit architecture integrating a transformer, a dual-phase interleaved step-up circuit, a voltage type auto charge pump circuit with a double-voltage rectifier circuit. The circuit of the invention integrates with the transformer, and combines the dual-phase interleaved boost circuit and the voltage type auto charge pump circuit at a primary side of the transformer to reduce the input current ripple. At a secondary side of the transformer, the circuit of the invention further combines the double-voltage rectifier circuit. The active switching elements can be further integrated in the dual-phase interleaved boost circuit to realize the soft switching technology while reducing EMI and the switching loss and increasing the circuit conversion efficiency.

Abstract: Consistent with an example embodiment, there is a controller for a resonant converter, wherein the controller is configured to operate the resonant converter in a high power mode of operation by adjusting a first control parameter to vary the output power and a low power mode of operation by adjusting a second control parameter to vary the output power. The controller is configured to set the value of the first control parameter when changing over between the high power mode of operation and the low power mode of operation such that the output power is substantially consistent during the changing over.

Abstract: A modified power converter circuit utilizes an RLC circuit tuned to the frequency of any instability in the power converter circuit in order to remove the instability in the circuit output. In one embodiment, a pair of RLC circuits are connected in parallel across the input capacitor and output capacitor of the power circuit topology, respectively. The capacitor and inductor of each RLC circuit act as filters having a period with the same value as the instability created by interaction of the respective input or output capacitor with the isolation transformer inductance and expose the resistor within each the RLC circuit to only the frequency of instability.

Abstract: The present invention discloses a control method for a soft switch circuit in a switch power source, which generates an alternating primary power filter current by controlling first and second primary power switching devices to be closed and opened, and generates an intermittent alternating resonant current in the same direction as the primary power filter current in a resonant branch by controlling forward and backward auxiliary switching devices to be closed and opened to thereby achieve closing of the first and second primary power switching devices at a zero voltage, and which generates a balance current with the same magnitude as and in the opposite direction to the resonant current in the resonant branch in at least a period of time during the resting of the resonant current by further controlling the forward and backward auxiliary switching devices to be closed and opened to thereby achieve an average current of zero across the resonant branch in a switching cycle.

Abstract: A converter, for use in high voltage direct and alternating current power transmission comprises a primary charge transfer converter. The charge transfer converter includes first and second primary terminals for connection to one or more electrical networks. The primary charge transfer converter also includes a plurality of charge transfer elements and a plurality of primary switching elements which are connected in a cascade circuit between the first and second primary terminals. Each charge transfer element includes at least one resonant circuit. The primary switching elements are operable to selectively cause charging and discharging of each resonant circuit to transfer charge between the charge transfer elements and thereby create a voltage difference between the first and second primary terminals.

Abstract: A switching power supply includes a series resonant circuit that includes a resonant inductor and a resonant capacitor connected in series with a primary winding of a converter transformer. By controlling turning on and off of first and second switching elements in a complementary manner, current is supplied to the series resonant circuit. A third switching element connected on the secondary side of the converter transformer is synchronized with the first switching element, and a fourth switching element is synchronized with the second switching element. If a switching frequency is less than a resonant frequency, turning on of the third and fourth switching elements is synchronized with turning on of the first and second switching elements, and turning off of the third and fourth switching elements is controlled, without being synchronized with turning off of the first and second switching elements, after half a resonant period has elapsed.

Abstract: A voltage converter (1a . . . 1g), in particular a resonant converter for converting an input AC or DC voltage (UE) into an output DC voltage (UA). On the secondary side, a first secondary capacitor (CS1) is arranged between the secondary partial windings (WS1, WS2) of a transformer (TR1); furthermore, a first secondary full-bridge rectifier (GS1) provides the output direct voltage (UA), the inputs of which are connected to a secondary partial winding (WS1, WS2) each of the transformer (TR1), resulting, at the input of the first secondary full-bridge rectifier (GS1), in a series connection including the secondary partial windings (WS1, WS2) and the first secondary capacitor (CS1). Finally, the voltage converter (1a . . .

Abstract: An image forming apparatus includes an image carrier and the following elements. A charging unit generates a charging electric field and charges the image carrier with the charging electric field. An exposure unit exposes the charged image carrier to light and forms an electrostatic latent image on the image carrier. A developing unit generates a developing electric field and develops the electrostatic latent image. A transfer unit transfers the developed image onto a transfer subject. At least one of the charging electric field and the developing electric field is generated by a bias power supply unit including a transformer having a primary winding and a secondary winding, and also including the following elements. A switch circuit supplies a current to the primary winding of the transformer by switching a switching device. A modulator circuit generates a PWM modulation signal. A waveform setting unit sets a waveform of a carrier signal.

Abstract: According to some preferred embodiments, power converter includes a comparator circuit with feedback from current-fed PI or PID control to select one of two regeneration times of at least one active clamp: i) wherein at low loads a regeneration circuit is turned ON for substantially an entire current-transfer cycle such as to avoid output of current-fed converter continuing to rise; and ii) wherein at high loads the regeneration period is reduced to between about ¼ to ½ of a resonance-frequency cycle so that a resonance between the regeneration capacitance and the transformer's leakage inductance avoids excessive ringing currents and/or lost efficiency.

Abstract: This invention relates to a LLC resonant converter for full input voltage range and its control method. The full voltage range LLC resonant converter comprises a LLC resonant converter circuit, a current type main loop current sampler, a rectifier, a main loop energy quantifier, an energy comparator, a return-to-zero pulse generator, an oscillator, and a split phase controller. The LLC resonant converter is configured to turn on electronic switches with ZVS state in full input voltage range. This invention realizes the full voltage working range of LLC resonant converter, guarantees its reliability, and enables designing a LLC converter to be a solid state converter. The LLC resonant converter can be widely used in applications such as non-contact charging stations for electric vehicle, electromagnetic inductance heating and switch power.

Abstract: Disclosed is a bi-directional battery power inverter (1) comprising a DC-DC converter circuit element (3) to which the battery (2) can be connected in order to generate an AC output voltage from a battery (2) voltage in a discharging mode while charging the battery (2) in a charging mode. The inverter (1) further comprises an HF transformer which forms a resonant circuit along with a resonant capacitor (6). In order to increase the efficiency of said battery power inverter, the transformer is provided with two windings (11, 12) with a center tap (20) on the primary side, said center tap (20) being connected to a power electronic center-tap connection with semiconductor switches (21, 31) while a winding (13) to which the resonant capacitor (6) is serially connected provided on the secondary side.