Abstract: An electrical component for surface mounting, such as a DC-DC power converter includes a body portion including one or more surface mounting pins to connect the body portion to a circuit board, and first and second circuit boards including respective circuit elements mounted thereon. The first and second circuit boards are mounted on the body portion, such that sides of the first and second circuit board on which the circuits are mounted face the interior of the device and the reverse sides of the first and second circuit boards define an exterior surface of the component. In this way, no separate housing for the component is required. The size of the electrical component can therefore be kept small, and protection provided to the circuit elements by the reverse side of the circuit board.

Abstract: A start-up circuit includes a switching-device control circuit arranged to receive an input voltage and to provide a switching-device control signal, a switching device arranged to be controlled by the switching-device control signal and to provide a start-up signal, a power-converter control circuit arranged to receive the start-up signal and to provide a power-converter control signal, and a power converter arranged to receive the power-converter control signal and to provide an auxiliary output signal. The switching control circuit is arranged to receive the auxiliary output signal such that, when the auxiliary output signal reaches a predetermined level, the switching-device control circuit stops providing the switching-device control signal.

Abstract: An inductor winding includes first, second, and third arms, a middle portion extending between and connected to at least two of the first, second, and third arms and arranged to support a winding core mounted thereon, and first, second, and third legs extending downwardly from the first, second and third arms, respectively, and arranged to be mounted on a circuit board. The first, second, and third legs are arranged to provide three-point contact with the circuit board, and the inductor winding is arranged to provide a space between a bottom surface of the winding core mounted on the middle portion and an upper surface of electronic components mounted on the circuit board.

Abstract: A power conversion system includes an input terminal that is arranged to be connected to a voltage source; a transformer having a first winding connected to the input terminal and a second winding connected to an output terminal of the power conversion system, either the first winding or the second winding is provided with at least three taps that are arranged to divide the first winding or the second winding into at least two sub-windings; at least one tap switch connected to the at least two sub-windings; a control circuit connected to the at least one tap switch; and at least one switch connected to the at least one tap switch. The control circuit is arranged to control the at least one tap switch to control the turn ratio of the transformer.