Abstract: A power converter can include a DC-DC converter having an output with an active power buffer coupled thereto. The active power buffer can include an energy storage capacitor and one or more switching devices selectively coupling the capacitor to the output to alternately store energy in and discharge energy from the capacitor. Control circuitry can include a DC-DC converter control loop that operates the DC-DC converter to regulate an average voltage across the capacitor and an active power buffer control loop that operates the one or more switching devices of the active power buffer to regulate an output voltage of the power converter. The DC-DC converter control loop can include a relatively slower control loop that controls the DC-DC converter during steady state load conditions and at least one relatively faster control loop that controls the DC-DC converter during transient load conditions.

Abstract: A power converter can include a rectifier that receives an AC input voltage and produces a rectified output voltage, a power factor correction (PFC) converter having an input coupled that receives the rectified output voltage of the rectifier and an output that provides an intermediate DC bus voltage, a DC-DC converter having an input that receives the intermediate DC bus voltage and produces a regulated DC output voltage, and control circuitry for the PFC converter stage that includes a relatively slower control loop that controls the PFC converter during steady state load conditions and at least one relatively faster control loop that controls the PFC converter during transient load conditions.

Abstract: A power converter can include an input boost converter stage having an input configured to receive a rectified AC input voltage and an output configured to deliver a DC bus voltage and a second switching converter stage having an input configured to receive the DC bus voltage and an output configured to deliver a regulated output voltage. The input boost converter may be configured to be operated in a flat current mode to maintain a substantially constant DC bus voltage over a broad range of AC input voltages. The input boost converter may be further configured to be operated in an active blanking mode, wherein operation of the boost converter is prevented during a controlled blanking interval of each cycle of the rectified AC input voltage. The controlled blanking interval may be increased responsive at least in part to an increase in the AC input voltage and/or may be decreased responsive at least in part to a decrease in the AC input voltage.

Abstract: A power converter can include an input boost converter stage having an input configured to receive a rectified AC input voltage and an output configured to deliver a DC bus voltage and a second switching converter stage having an input configured to receive the DC bus voltage and an output configured to deliver a regulated output voltage. The input boost converter may be configured to be operated in a flat current mode to maintain a substantially constant DC bus voltage over a broad range of AC input voltages. The input boost converter may be further configured to be operated in an active blanking mode, wherein operation of the boost converter is prevented during a controlled blanking interval of each cycle of the rectified AC input voltage. The controlled blanking interval may be increased responsive at least in part to an increase in the AC input voltage and/or may be decreased responsive at least in part to a decrease in the AC input voltage.

Abstract: A power converter can be configured to convert an AC input voltage into a regulated DC output voltage while maintaining the input current in phase with the rectified AC input voltage. A control circuit of the power converter may be configured to selectively enable switching of at least one switching device of the power converter responsive to a determination that the input voltage is greater than a threshold voltage and to selectively disable switching of the at least one switching device responsive to a determination that the rectified AC input voltage is less than the threshold voltage. The control circuit may be configured to selectively enable and disable switching using an active burst mode signal having a frequency lower than a switching frequency of the converter. The control circuit may be still further configured to operate at least one switching device of the converter in a zero voltage switching condition.

Abstract: A primary resonant flyback converter may include a primary winding, a resonant capacitor in series with the primary winding, a secondary winding magnetically coupled to the primary winding, and an output electrically coupled to the secondary winding. A main switch may be operated to energize the primary winding when closed and transfer energy stored in the primary winding to the secondary winding when open. An auxiliary switch may be configured to switch complimentarily to the main switch, thereby allowing a resonant current to circulate through the primary winding and capacitor. Switch timing may be controlled to produce a desired output voltage. The converter may also include an input inductor that receives an input voltage, presenting an improved power factor to an AC input power source and in conjunction with the switching devices boosts a rectified AC input voltage to a DC voltage bus of the converter.

Abstract: A primary resonant flyback converter may include a primary winding, a resonant capacitor in series with the primary winding, a secondary winding magnetically coupled to the primary winding, and an output electrically coupled to the secondary winding. A main switch may be operated to energize the primary winding when closed and transfer energy stored in the primary winding to the secondary winding when open. An auxiliary switch may be configured to switch complimentarily to the main switch, thereby allowing a resonant current to circulate through the primary winding and capacitor. Switch timing may be controlled to produce a desired output voltage. The converter may also include an input inductor that receives an input voltage, presenting an improved power factor to an AC input power source and in conjunction with the switching devices boosts a rectified AC input voltage to a DC voltage bus of the converter.

Abstract: A primary resonant flyback converter may include a primary winding, a resonant capacitor in series with the primary winding, a secondary winding magnetically coupled to the primary winding, and an output electrically coupled to the secondary winding. A main switch may be operated to energize the primary winding when closed and transfer energy stored in the primary winding to the secondary winding when open. An auxiliary switch may be configured to switch complimentarily to the main switch, thereby allowing a resonant current to circulate through the primary winding and capacitor. Switch timing may be controlled to produce a desired output voltage. The switching frequency may be varied as a function of output load, input voltage and/or voltage ripple on a DC bus of the converter. Switching may also be temporarily disabled responsive to a decrease in output load and re-enabled responsive to an increase in output load.

Abstract: The disclosed embodiments provide a system that facilitates operation of a power adapter in hiccup mode. The system includes a bleeding mechanism that reduces a hiccup time of the hiccup mode by increasing a leakage current of the power adapter. The system also includes an activation mechanism that activates the bleeding mechanism upon detecting a voltage drop associated with the hiccup mode.

Abstract: The disclosed embodiments provide a system that facilitates operation of a power adapter in hiccup mode. The system includes a bleeding mechanism that reduces a hiccup time of the hiccup mode by increasing a leakage current of the power adapter. The system also includes an activation mechanism that activates the bleeding mechanism upon detecting a voltage drop associated with the hiccup mode.

Abstract: The disclosed embodiments provide an apparatus that controls a flyback converter for use with a computer system. During operation, the apparatus senses an output voltage and output current of the flyback converter. The apparatus then switches a mode for controlling the flyback converter from a discontinuous mode to a continuous mode based on the sensed output voltage and the sensed output current.