Power factor correction circuit with a coil
View Patent ↗The switched-mode power supply according to the invention has a power factor correction circuit, which operates on the principle of a current pump and has a first coil for damping voltage spikes, as well as a second coil for power factor correction. The two inductances are in this case connected in series and are arranged on a coil former and on a common core. In one preferred exemplary embodiment, an E/E ferrite core is used as the core, and a coil former with chambers is used as the coil former, with the windings of the two inductances being arranged in different chambers. An empty chamber, which is located in the region of the air gap in the core, is advantageously arranged between the two inductances. This partially decouples the two inductances by means of the air gap, so that the damping response of the first inductance is better.
1. Switched-mode power supply having a rectifier element, a dowstream energy storage capacitor, a transformer, whose primary winding is coupled to the energy storage capacitor and is connected in series with a switching transistor, and having a power factor correction circuit, which forms a current path between the rectifier element and one connection of the primary winding, and which has a first coil for damping voltage spikes, as well as a second coil for power factor correction, wherein
the two coils having a common core, and the windings of the two coils are arranged on a common coil former,
the coil former comprises chambers, and the windings of the two coils are arranged in different chambers,
the windings have opposite winding senses, so that their magnetizations partially cancel one another out in the core, and
an empty chamber is located between the two windings.
2. Switched-mode power supply according to claim 1 , wherein the core is an E/E ferrite core, and the coil former is located above the inner core limb.
3. Switched-mode power supply according to claim 2 , wherein the inner core limb E/E ferrite core has an air gap, and in that the empty chamber is located in the region of this air gap.
4. Switched-mode power supply according to claim 1 , wherein the two coils are connected in series and have a tap, which is located in between them and which is connected via a capacitor to the energy storage capacitor.
5. Coil for a switched-mode power supply having a power factor correction circuit, wherein
the coil has a coil former on which a winding of a first coil for damping voltage spikes is wound, and on which a winding of a second coil, which is connected in series with the first winding, for power factor correction is wound,
the two coils have a common core and the coil former comprises chambers, the windings of the two coils being arranged in different chambers, and
an empty chamber is located between the two windings.
6. Coil according to claim 5 , wherein the coil has an E/E ferrite core, above whose inner core limb the coil former is arranged, and in that the two coils are wound over in each case one inner core limb half such that they are physically separated.
7. Coil according to claim 5 , wherein windings of the two coils have opposite winding senses.