Delta Electronics, Inc.

Stmicroelectronics S.r.l.

Virginia Tech Intellectual Properties Inc

Laszlo Huber

Milan M Jovanovic

Chien-Chung Chang

Peter Mantovanelli Barbosa

Daofei Xu

Haibin Song

Milan M Jovanović

Brian T Irving

Alpha Zhang

Fred C Lee

Jinfa Zhang

Claudio Adragna

Aldo Vittorio Novelli

Yuequan Hu

Tomas Sadilek

Antonio Borrello

Zhiyu Shen

Chia-Hsiong Huang

Misha Kumar

Jindong Zhang

A power factor correction (PFC) converter includes an inductor to electrically connect to an alternating current (AC) source, a first set of switches to be electrically connected to a terminal of the inductor at one end and to a negative output terminal at an opposite end, and a second set of switches to be electrically connected to the terminal of the inductor at one end and to a positive output terminal at an opposite end. An output voltage of the PFC converter is between the positive output terminal and the negative output terminal. Two or more flying capacitors are connected between different pairs of adjacent ones of the first set of switches and corresponding adjacent ones of the second set of switches. A controller controls duty cycle of the first set of switches and the second set of switches based on balancing voltages of the two or more flying capacitors.

Flying capacitor multi-level power factor correction converter of power supply with active balancing of voltage of flying capacitors

A flyback power converter includes a hybrid clamp circuit and a corresponding power management unit that substantially optimizes the performance of the flyback power converter in its entire line and load ranges. The clamp circuit, which is connected in parallel to a primary winding of the flyback transformer, includes a parallel combination of a capacitor and resistor that is connected in series with a parallel combination of a switch and a diode. By sensing the operating conditions, the power management circuit configures the clamp circuit either as a passive clamp or as an active clamp. In the passive-clamp configuration, the switch is kept turned off. In the active-clamp configuration, the switch operates with pulse-width modulation (PWM) which enables ZVS turn-on of the main switch.

Power converter and method of control thereof

A DC/DC converter may be formed out of the combination of a first converter that is optimized to transfer energy from a voltage source to a load, and a second converter that receives a control signal derived from the load voltage to regulate the load voltage. The DC/DC converter may be configured as a sigma converter, a delta converter, or a sigma-delta converter. The mode of operation being selected according to the source voltage or the load voltage, either of which may vary over a wide range.

Sigma, delta and sigma-delta DC/DC converters for wide input and output voltage ranges

A power supply includes multiple power modules and a control circuit. Input terminals of the power modules are connected in star connection such that each power module receives a phase input voltage. Output terminals of the power modules are connected in parallel. Each power modules includes a first and a second converter. The first converter converts the phase input voltage into an intermediate bus voltage. The second converter outputs a DC supply voltage according to the intermediate bus voltage. The control circuit is coupled to the power modules and configured to output first and second driving signals to control the first and second converters in the power modules. A bus voltage average value is calculated by the control circuit according to the intermediate bus voltages of the power modules, and the first and the second driving signals for the power modules are generated according to the bus voltage average value.

Power supply and control method thereof

A power supply having an input and an output, includes a power converter coupled between the input and output of the power supply including at least one switch that is controlled by comparing a sensed voltage, the sensed voltage corresponding to a current flowing through the switch, to a reference voltage. A controller, in response to a change detected in a switching frequency of the switch, reduces audible noise generated by the power supply by at least one of: adjusting the reference voltage; adjusting the current sense voltage; or adjusting a resistance used to generate the sensed voltage.

Switch-mode power supply having reduced audible noise

A variable inductor comprises one or more magnetic cores providing magnetic flux paths. An inductor coil is wound around one or more inductor sections of the one or more magnetic cores. An inductor magnetic flux flows through one or more closed flux paths along the inductor sections of the magnetic core. A control coil is wound around one or more control sections of the one or more magnetic cores. A control magnetic flux flows through one or more closed flux paths along the control sections of the magnetic core. Under this arrangement, the inductor magnetic flux substantially does not flow through the control sections of the magnetic core and the control magnetic flux substantially does not flow through the inductor sections of the magnetic core. The closed flux paths associated with the inductor magnetic flux and the closed flux paths associated with the control magnetic flux share one or more common sections of the magnetic core not including the control sections and inductor sections. The inductance of said variable inductor is varied by varying said control magnetic flux.

Current-controlled variable inductor

Control device for a switching converter structure comprising at least a first and a second interleaved converter, wherein the control device is configured to designate one converter as master and at least the other converter as slave, to set a time delay of the operating cycle of the slave converter and to synchronize the master and the at the least one slave converter.

Control method and device for a system of interleaved converters using a designated master converter

A single-stage input-current-shaping (SICS) flyback converter achieves substantially reduced conduction losses in the primary side of the SICS flyback converter by connecting a bypass diode between the positive terminal of a full-bridge rectifier and the positive terminal of an energy-storage capacitor. An effective current interleaving between an energy-storage inductor and the bypass diode is thus obtained in the SICS flyback converter around the peak of the rectified line voltage, resulting in a significantly reduced input-current ripple and reduced current stress on the switch. Further, by rearranging the rectifiers in the ICS part of the SICS flyback converter in such a way that the energy-storage capacitor and the ICS inductor are connected to the ac line voltage through only two rectifiers, one diode forward-voltage drop is eliminated, which results in a substantially reduced conduction loss in the primary-side rectifiers.

AC/DC flyback converter

A single-stage input-current-shaping (S.sup.2 ICS) converter of the present invention integrates a voltage-doubler-rectifier front-end with a DC/DC output stage. Two families of voltage-doubler S.sup.2 ICS converters are disclosed. In one family, a 2-terminal dither source is provided between a boost inductor and a common input terminal of a storage capacitor and the DC/DC output stage. The 2-terminal dither source includes two paths connected in parallel: a first path for charging and a second path for discharging the boost inductor at a high frequency (HF). In the other family, a 3-terminal dither source includes a third terminal coupled to a pulsating node of the DC/DC output stage. In the 3-terminal dither source, the HF charging path of the boost inductor is coupled between the boost inductor and the pulsating node of the DC/DC output stage, while the HF discharging path of the boost inductor is coupled between the boost inductor and the common input terminal of the storage capacitor and the DC/DC output stage. Due to the voltage-doubler-rectifier front-end, reduction of line-current harmonics can be achieved with a higher conversion efficiency, as compared to a corresponding S.sup.2 ICS converter with a conventional full-bridge rectifier. In addition, a converter of the present invention requires storage capacitors of a lower voltage rating and a smaller total capacitance than the conventional S.sup.2 ICS counterpart. The present invention thereby reduces the size and the cost of the power supply.

Single-stage input current shaping technique with voltage-doubler

A new single stage, single switch input current shaping circuit features substantially reduced turn-on switching losses of the switch in the flyback-converter. In this technique, the turn-on switching losses due to the discharge of the output capacitance of the switch are reduced by turning on the switch when its voltage is minimal or close to the minimal. To achieve the turn-on loss reduction for a wide range of line and load conditions, the flyback-converter stage is continuously operated at the boundary of the CCM and DCM by employing a variable-frequency control. In this technique the boost inductor can work either in the DCM or the CCM. The wide-bandwidth, variable-frequency control is implemented by detecting the onset of the DCM/CCM boundary and, subsequently, turning the switch on at the minimum switch voltage. The switch is turned off when the increasing primary current reaches a reference level set by the output-voltage feedback control circuit.

AC/DC flyback converter with improved power factor and reduced switching

A new single-stage, single-switch, input-current-shaping technique which combines the boost-like input-current shaper with a continuous-conduction-mode dc/dc output stage is described. Due to the ability to keep a relatively low voltage (&lt;450 Vdc) on the energy-storage capacitor, this technique is suitable for the universal line-voltage applications. The voltage on the energy-storage capacitor is kept within the desirable range by the addition of two transformer windings. One winding appears in series with the boost inductor during the on time, whereas the other winding appears in series with the same inductor during the off time. By connecting the windings so that the voltages across them when they conduct the inductor current are in opposition to the input voltage, the volt-second balance of the boost-inductor core is achieved at a substantially lower voltage of the energy-storage capacitor compared to the other known approaches. In addition, for the forward-converter-type single-stage, single-switch input-current shapers, a direct transfer of a part of the input energy is achieved by the winding which appears in series with the boost inductor during the on time, while for the flyback implementation a direct transfer of a part of the input energy is achieved by the winding which appears in series with the boost inductor during the off time.

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Cary, NC, United States of America

Laszlo Huber