Abstract: A phase-shifted full bridge converter is provided. The converter includes a transformer having a primary winding and a secondary winding having a center tap, an input stage comprising a full bridge switching circuit coupled to the primary winding, and an output stage coupled to the secondary winding. The output stage includes a circulating current control circuit to provide a portion of output current to reduce output current provided from the secondary winding during a freewheeling time period and reduce the circulating current in the primary winding.

Abstract: An envelope tracking power supply has a multiple-output DC/DC converter, a switch bank, an output voltage selector and an output filter. The DC/DC converter has an alternating current generating portion and a full rectifying portion. The alternating current generating portion, typically a LC circuit, can receive an input voltage and operate at zero voltage switching. The full rectifying portion includes at least one secondary winding and one voltage doubler output. Each voltage doubler has a first transistor, a second transistor, a first capacitor and a second capacitor. The transistors used as rectifier devices allow currents to flow bi-directionally and sink and source the currents from and to output capacitors to keep their voltage balance. Secondary windings and output capacitors are connected in series respectively. A switch bank selects a desired voltage from the series connected capacitors and connects it to the output filter.

Abstract: A controller for a DC/DC converter can include a first error analog to digital converter (EADC) configured to detect a primary voltage from a secondary side of a transformer and generate a first error signal corresponding to the primary voltage. The first error signal is generated based on a comparison between a first reference voltage and the detected primary voltage. A first accelerator can be configured to process the first error signal and generate a first compensation signal that is a primary voltage variation signal used for feedforward control. A second EADC and a second accelerator can be configured to provide a output voltage feedback control. A compensation signal of the first accelerator can be used to scale the second accelerator output to facilitate fast feedforward control.

Abstract: In a first aspect, a control circuit is provided for use with a switch-mode power stage that provides an output voltage signal and an output current signal at an output power. The switch-mode power stage has a nominal voltage, a nominal current, a maximum current, an output power and a maximum power. The control circuit includes a voltage control loop and a current control loop, and the control circuit uses the voltage control loop to provide voltage mode control if the output current signal is greater than or equal to the nominal current and less than the maximum current, wherein the output power is substantially constant. Numerous other aspects are also provided.

Abstract: A method of operating a power factor correction (PFC) circuit and a corresponding power factor correction circuit include determining an adaptive switching frequency of the PFC circuit related to a current of the boost inductor of the PFC circuit, and operating the PFC circuit at a light load based on the adaptive switching frequency.

Abstract: A DC-to-DC converter has a leading full-bridge inverter and a lagging full-bridge inverter for receiving a DC input and producing respective AC output voltages. A full-wave rectifier circuit rectifies the AC output voltages to produce a rectified output voltage, which is filtered by a current doubling output filter circuit to produce a DC output voltage. A master phase-shift controller and a slave phase-shift controller respectively provide first and second control signals to the leading full-bridge inverter and third and fourth control signals to the lagging full-bridge inverter to regulate the DC output voltage by changing a phase of the second and fourth control signals with respect to the first and third control signals below a predetermined DC output voltage, and by changing a phase of the third and fourth control signals with respect to the first and second control signals above the predetermined threshold.

Abstract: An embodiment of the invention provides a method of reducing surge current in an LLC converter. The LLC converter comprises a switching circuit having a first switch and a second switch, a resonant circuit, and a rectification circuit. During start up of the LLC converter, first and second signals having a fixed period and a variable duty cycle are applied to the first and second switches respectively. When a predetermined voltage on a load configured to be coupled to the rectification circuit is reached, the first and second signals are changed to signals having a variable period and a fixed duty cycle.

Abstract: An embodiment of the invention provides a method of reducing surge current in an LLC converter. The LLC converter comprises a switching circuit having a first switch and a second switch, a resonant circuit, and a rectification circuit. During start up of the LLC converter, first and second signals having a fixed period and a variable duty cycle are applied to the first and second switches respectively. When a predetermined voltage on a load configured to be coupled to the rectification circuit is reached, the first and second signals are changed to signals having a variable period and a fixed duty cycle.

Abstract: Disclosed is a family of new DC/DC converters and a new control method. The converter comprises two bridge inverters, two full-wave rectification circuits and a current-doubler filter. Each inverter is able to generate a symmetrical and isolated AC output voltage. Phase-shift control is employed to control the phase difference between the two bridge inverters. By shifting the phase, the converter changes the two inverters' output voltage overlapping area to regulate its output voltage. The bridge inverters always operate at 50% duty cycle, like an open loop Bus Converter, to achieve wide-range zero voltage switching and eliminate circulating current for normal operation. For low output voltage regulation and soft start, Pulse Width Modulation (PWM) control is used. The converters and the control method improve power conversion efficiency, maximize magnetic component utilization, reduce semiconductor stress and decrease EMI emission.

Abstract: A controller for use with a current-controlled frequency-modulated power factor corrector having a power switch therein, and a method of regulating the same. In one embodiment, the controller includes a sensing circuit configured to detect a sense current that is representative of an input current to the power factor corrector. The controller also includes a frequency modulation circuit, coupled to the sensing circuit, configured to provide a signal that causes at least one of: (a) an increase of a switching frequency of the power switch when the input current increases, and (b) a decrease of the switching frequency of the power switch when the input current decreases.

Abstract: An electronic battery equalization circuit that equalizes the voltages of a plurality of series connected batteries in a battery pack. The current waveform is in the shape of a ramp for providing zero current switching. The ramp converter power circuit has at least one semiconductor device and a transformer coupled to the equalizing voltage supply source. The transformer has a primary winding circuit and at least one secondary winding circuit. In one embodiment, each secondary winding circuit is connected to a different pair of batteries. The equalizing current is provided to the lowest voltage batteries in one half of the battery pack during one half of the charging cycle. The equalizing current is then provided to the lowest voltage batteries in the other half of the battery pack during the other half of the charging cycle. In another embodiment, each secondary winding circuit is connected to a different single battery.