A filtering circuit includes at least two common-mode filters that are electrically coupled in series and magnetically coupled. The first common-mode filter includes first and second spiral inductors that are positively magnetically coupled and electrically isolated from each other. The second common-mode filter includes third and fourth spiral inductors that are positively magnetically coupled and electrically isolated from each other. The first and third spiral inductors are electrically connected in series and negatively magnetically coupled. Likewise, the second and fourth spiral inductors are electrically connected in series and negatively magnetically coupled.

A device for filtering at least one signal has a first magnet core and at least one first coil. The first coil has a first coil connection, a second coil connection, a first coil element, a second coil element and a connecting section. The first coil connection is electrically connected to the second coil connection via the first coil element, the connecting section and the second coil element. The first coil element has a first coil axis and the second coil element has a second coil axis. The first coil axis and second coil axis are arranged parallel to and at a distance from one another. The first magnet core extends both through the first coil element and also through the second coil element.

A noise suppression filter includes a resonator, a ground plane, and a set of differential transmission lines. The set of differential transmission lines includes a first meander line and a second meander line formed in a first circuit layer. The resonator is formed in a second circuit layer and includes a first long arm, a second long arm, and a short arm extended form a same point to form a T-shape. The ground plane is formed in a third circuit layer and is coupled to the first long arm and the second long arm through vias. The first meander line is detoured along the inner sides of the first long arm and the short arm, and the second meander line is detoured along the inner sides of the second long arm and the short arm.

A filter module for reducing differential and common mode electrical noise may include at least a first electrically conductive busbar and a second electrically conductive busbar spaced apart from the first busbar, an at least partially electrically conductive housing at least partially enclosing the first busbar and the second busbar, at least a first common mode choke and a second common mode choke arranged in the housing and spaced apart from each other, at least a first bypass capacitor electrically connected to the first busbar and the second bus bar, at least a second bypass capacitor electrically connected to the first busbar and a midpoint, and at least a third bypass capacitor electrically connected to the second busbar and the midpoint.

To improve the performance of the voltage filter. Rather than reducing an area of a region surrounded by a closed loop formed in a voltage filter 12A, an induced electromotive force generated in the voltage filter 12A itself is reduced by forming a pair of a closed loop CA and a closed loop CB in which the directions of the generated induced electromotive forces are opposite to each other by making a wiring 100 (anode wiring) intersect a wiring 200 (cathode wiring).

A common-mode choke coil includes a first filter unit and a second filter unit, each of which serves as a common-mode filter unit and is formed by arranging a primary coil and a secondary coil in a stacking direction. Of the first filter unit and the second filter unit, the first filter unit has a resonant frequency different from that of the second filter unit, and the line length is different between the primary coil and the secondary coil.

A noise filter includes a metallic bottom plate, a case main body integrally formed with a terminal strip and attached to the bottom plate, and a capacitor including a terminal configured to be connected in the terminal strip. The noise filter further includes a capacitor housing part formed inside the terminal strip in the case main body, the capacitor housing part being configured to house the capacitor, and an inductor disposed on a top surface side of the case main body, the inductor comprising a terminal configured to be connected in the terminal strip. The capacitor housing part houses the capacitor, in a state where the capacitor is inclined with respect to the bottom plate, so that a lead part of the terminal of the capacitor is positioned on an upper end side of the capacitor in an inclination direction.

A noise suppressor includes a first differential-mode transmission module, a second differential-mode transmission module and a common-mode absorption module. The first and second differential-mode transmission modules are configured to receive a differential signal at one of the first and second differential-mode transmission modules, and output the differential signal at the other of the same. The common-mode absorption module is electrically connected to a reference node, and is configured to absorb common-mode noise of the differential signal from at least one of the first differential-mode transmission module or the second differential-mode transmission module.

A noise filter includes a first capacitor and a second capacitor which are two line-to-line capacitors. Currents flowing through the first capacitor and the second capacitor are in directions opposite to each other, and meanwhile, currents flowing through a first connection wire and a second connection wire are in the same direction and parallel to each other. Accordingly, magnetic coupling is caused between the connection wires and the line-to-line capacitors. Thus, the residual inductance of a line-to-line capacitor itself is reduced, whereby an attenuation characteristic for normal mode noise is further improved.

The present disclosure relates to an electromagnetic interference (EMI) filter for preventing noise emitted from a power line cable, and an isolated type active EMI filter having no additional elements on a power line. The EMI filter includes a common-mode (CM) choke disposed on a power source side, a Y-cap disposed on an EMI source side, and a sensing winding configured to sense a current. The EMI filter also includes an amplifier configured to amplify the noise current, and a transformer configured to inject a signal of the secondary coil into the Y-cap as a compensation signal.