Abstract: Example switch mode power supplies, including buck converters, with indirect, switch-mode feedback for pulse width modulation and duty cycle control are described and shown. Non-idealities are corrected with several example compensation methods and apparatus, including current sense and corresponding voltage adjustment.

Abstract: Apparatus and method for retrofitting a mobile electronic device, which has an input power receptacle located on its side, to receive power from a power delivery pad that has a flat power delivery surface. A connector assembly is connectable to the mobile electronic device by plugging a connector into the input power receptacle of the device. A power receiver assembly connects pivotally and electrically to the connector assembly by magnetism. The power receiver assembly is pivotal to position a power receiver hub, which is at a fixed distance from the connector assembly, over an axis of the mobile device, where an anchor comprising magnetic material or a mechanical attachment apparatus is adhered to the surface of the mobile device, and the hub is attached to the anchor by magnetism also, so that it is simply and easily detachable and re-attachable. The connector is adjustable in the connector assembly to position the power receiver assembly flush with the surface of the mobile device.