Apple Inc.

Chanwit Prasantanakorn

Bharat K Patel

Yantao Song

Abby Cherian

A power converter can include a switching bridge having two input terminals that receive an input voltage and a switch node coupled to a primary winding of a transformer; at least one rectifier device coupled between a secondary winding of the transformer and an output of the power converter; and a common mode noise compensation capacitor. A first terminal of the common mode noise compensation capacitor can be coupled to a connection between the secondary winding of the transformer and the at least one rectifier device, and a second terminal of the common mode noise compensation capacitor can be coupled to one of the two input terminals. The common mode noise compensation capacitor can be coupled to an energized or a grounded input terminal. The common mode noise compensation capacitance can be selected to be equal to the turns ratio of the transformer times the parasitic capacitance of the transformer.

Common mode noise cancellation for LLC resonant converters

A power factor correction circuit can include an input that receives a rectified AC input voltage; at least one switching device operable to control an input current of the power factor correction circuit to be in phase with the rectified AC input voltage; and control circuitry that controls the at least one switching device to produce a clipped sinusoidal input current, thereby increasing peak load capacity of the power factor correction circuit. The control circuitry can operate the at least one switching device in a critical conduction mode. The power factor correction circuit can further include an inductor having an inductor current therethrough controlled by the at least one switching device and the control circuitry. The inductor can be sized for a peak current corresponding to a peak of the clipped sinusoidal input current.

PFC design technique for high peak load

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.

Power supply with active power buffer

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.

A power converter can include a DC-DC converter stage having an input coupled to an input of the power converter and an output coupled to an output of the converter and an active power buffer coupled to the output of the power converter. The active power buffer can further include an energy storage capacitor and one or more switching devices selectively coupling the energy storage capacitor to the output of the power converter so as to alternately store energy in and discharge energy from the energy storage capacitor. Control circuitry of the power converter can include a first control loop that operates the DC-DC converter stage to regulate an average voltage across the energy storage capacitor of the active power buffer and a second control loop that operates the one or more switching devices of the active power buffer to regulate an output voltage of the power converter.

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Santa Clara, CA, United States of America

Chanwit Prasantanakorn