A ballast for a gas discharge lamp (2) has an inductor in the load circuit (1) and a transformer (14) in a driver circuit (11) for an inverter (7) having high-impedance switch elements (8). In order to reduce the circuit complexity, the primary winding Tp and the secondary winding Ts of the transformer (14) should have a common core (16).

Ballast for a gas discharge lamp

A switching power supply has a transformer for power transmission. A core is provided having an intermediate leg and at least a pair of external legs arranged at equal intervals from the intermediate leg; a first printed coil is provided on a first substrate which has an intermediate hole and a pair of external holes respectively inserted in the intermediate leg and the pair of external legs of the core, the first printed coil being wound around the intermediate hole; a second printed coil is provided on a second substrate which has an intermediate hole and a pair of external holes respectively inserted in the intermediate leg and the pair of external legs of the core, the second printed coil including a pair of external printed coils which are connected in series and are respectively wound around the pair of the external holes and each having the same number of turns but wound in opposite directions. The pair of external printed coils of the second printed coil generate magnetic fields in opposite directions to each other in the intermediate leg such that the magnetic fields in the intermediate leg cancel each other and induce no induction voltage in the first printed coil, and induction voltages induced in the external printed coils of the second printed coil by magnetic flux generated by the first printed coil are substantially canceled, whereby the first printed coil and the second printed coil form separate inductors which are not magnetically coupled. A third printed coil is provided on a third substrate which has an intermediate hole and a pair of external holes respectively inserted in the intermediate leg and the pair of external legs of the core, the third printed coil being wound around the intermediate hole, whereby the first printed coil is magnetically coupled with the third printed coil to form a first transformer; and further wherein the tranformer for power transmission comprises the first transformer.

Coil device and switching power supply apparatus using the same

Novel switched mode boost-buck integrated magnetic power converters are disclosed featuring two winding bobbins, a new boost section with enhanced gain, means for operating the converter in a continuous mode of energy storage under minimum output loading conditions while providing adequate time for removing the magnetization energy of the transformer part of the integrated magnetics, and other new and different converter topologies.

Integrated-magnetics power converter

Combined transformer and choke unit

In the case of the circuit arrangement for the radio-frequency operation of a lamp, especially of a low-pressure discharge lamp (LP), the switched-mode power supply is controlled by means of at least one additional auxiliary winding (HW1, HW2) on the resonant inductance (L2), via in each case one pulse-shaping and phase-shifting network, without a dedicated pole point. The pulse-shaping and phase-shifting network consists in the case of voltage-controlled switching elements (T1, T2) of an RC low-pass filter (R3, C3; R4, C4) having one or more stages. It is possible to dispense with a separate current transformer as a result of this type of drive.

Circuit for operating a lamp

An inductor/transformer combination for operating high-pressure metal-vapour lamps in vehicle electrical systems is described, which has only a single magnetic core 6.

Ballast for a gas discharge lamp

References

Coil device and switching power supply apparatus using the same

Integrated-magnetics power converter

Combined transformer and choke unit

Circuit for operating a lamp

Choke-coil/transformer combination for operating high pressure metal vapor lamps of vehicle electrical systems