Abstract: A power factor correction circuit structure is described. The power factor correction circuit comprises a series connection of a first winding, a diode, an inductor and a first capacitor. The polarity of the first winding is opposite to that of the primary winding. A second capacitor is connected to the primary winding to control the primary winding and build a voltage across the first capacitor. This voltage is transferred to the first winding through the transformer to boost the first capacitor voltage and improve the power factor.

Abstract: The present invention describes a planar transformer having a plurality of juxtaposed magnetic cores as well as a two-layer printed circuit board for spiralling a plurality of windings. Each arm of a plurality of juxtaposed magnetic cores respectively goes through a corresponding hole in the middle of these windings, to magnetically couple the current in the main winding to the other windings.

Abstract: A power factor correction circuit structure is described. The circuit connects a bridge rectifier and a first capacitor in series. The first capacitor, a winding and a first switching device are also connected in series. The first switching device is the low-side switching device in a bridge converter. The first switching device, a second switching device and a second capacitor are also connected in series, The second switching device is the high-side switching device in the bridge converter and the second capacitor is the boost capacitor in the PFC circuit. The winding can be one additional winding of the main transformer in the bridge converter or an independent inductor.

Abstract: A power factor correction circuit structure is described. The circuit connects a bridge rectifier and a first capacitor in series. The first capacitor, a winding and a first switching device are also connected in series. The first switching device is the low-side switching device in a bridge converter. The first switching device, a second switching device and a second capacitor are also connected in series. The second switching device is the high-side switching device in the bridge converter and the second capacitor is the boost capacitor in the PFC circuit. The winding can be one additional winding of the main transformer in the bridge converter or an independent inductor.

Abstract: The present invention describes a planar transformer having a plurality of juxtaposed magnetic cores as well as a two-layer printed circuit board for spiralling a plurality of windings. Each arm of a plurality of juxtaposed magnetic cores respectively goes through a corresponding hole in the middle of these windings, to magnetically couple the current in the main winding to the other windings.

Abstract: The high efficiency amplifier system of the present invention dynamically changes the level of the supply voltage in response to changes of the input analog signal. The voltage supplied to the amplifier circuit is minimized to avoid the consumption of power.