A power filter is provided, including a circuit board module, an insulating base, several connect terminals, and an inductor. The circuit board module includes a circuit board and several electronic components, wherein the circuit board forms several connect holes thereon and the electronic components are electrically connected to the circuit board. The connect terminals are fixed on the insulating base and each has a connecting part and a clamping part, wherein the connecting parts are joined with the connect holes of the circuit board. The inductor includes at least one wire with both terminals clamped by the clamping parts, and the wire is electrically connected to the circuit board module through the connecting parts.

Disclosed are a two-stage noise filter, in which two filters are integrated, and an electronic device including the same. The two-stage noise filter includes a core configured to include a primary side and a secondary side opposite to the primary side; a first filter configured to include a first coil wound on the primary side of the core and a second coil wound on the secondary side of the core; a second filter configured to include a third coil wound on the primary side of the core in series with the first coil and a fourth coil wound on the secondary side of the core in series with the second coil; and an impedance balancer configured to keep a balance of impedance between the first and second filters.

The technology described in this document can be embodied in an apparatus that includes at least four magnetic cores, wherein each core is for supporting an inductor of a filter circuit. Each of the cores include a first section, and a second section separated from the first section by an adhesive layer. The apparatus also includes an air-core structure to store magnetic energy, the air-core structure including a set of focusing projections that define a hollow cavity. The individual focusing projections of the set are disposed on different sides of the hollow cavity to focus magnetic field from the at least four magnetic cores through the hollow cavity.

The present disclosure provides a switching power supply, an EMI filter, a common mode inductor and a wrapping method for the common mode inductor. The common mode inductor includes: a magnetic core; two multilayered coil windings symmetrically wrapped around the magnetic core; and two isolation gaps each of which is formed in respective one of the two multilayered coil windings, and is configured to divide, by beginning from a first layer, the respective one of the multilayered coil windings into two wrapping areas.

A power conversion apparatus includes: a busbar; a magnetic core disposed to surround the busbar; and a fixing member that supports the magnetic core and is secured to the busbar. A noise filter includes: a magnetic core disposed to surround a busbar of a power conversion apparatus, and a fixing member that supports the magnetic core and is secured to the busbar.

A filter device, method of manufacture and use thereof. The filter device comprises a foil-wound inductor formed by a first conductive foil strip having a first terminal and a second terminal, the first conductive foil strip wound around a core to form a plurality of winding layers such that the first terminal is proximate the core and the second terminal is located at the outermost winding layer, and a continuous dielectric insulating layer between the plurality of layers of the first conductive foil strip; and, a tunable capacitor formed by a second conductive foil strip at least partially encircling the outermost layer of the foil-wound inductor and a dielectric insulating layer disposed therebetween, the second conductive foil strip having a portion that can be trimmed to alter a capacitance between the second conductive foil strip and the first or second terminal of the foil-wound inductor. When used in a circuit, the tunable capacitor can be trimmed to compensate for parasitic capacitance associated with the foil-wound inductor.

The present disclosure provides a common mode noise filter that can improve attenuation characteristics of common mode noise over a wide frequency range. The common mode noise filter of the present disclosure includes: two magnetic sections and each of which is made of a magnetic material; and non-magnetic section disposed between magnetic sections in a stacking direction, non-magnetic section being made of a non-magnetic material. Moreover, the common mode noise filter further includes two coils and metal layer. Coils are disposed inside non-magnetic section while facing each other. Metal layer is formed inside at least one of two magnetic sections while being connected to the ground. Metal layers are positioned closer to a lower surface of magnetic section than an upper surface of magnetic section and closer to an upper surface of magnetic section than a lower surface of magnetic section.

Exemplary embodiments are disclosed of circuits for integrating and/or combining electromagnetic interference (EMI) filters with power lines without using capacitors. In exemplary embodiments, a circuit comprises a common mode inductor including first and second inductors. The first inductor is configured to be operable for providing a first impedance along a live wire of the circuit. The second inductor is configured to be operable for providing a second impedance along a neutral wire of the circuit. The circuit further includes a third inductor configured to be operable for providing a third impedance along a ground wire of the circuit.