In a common mode noise filter, first coil (12) includes first coil conductor (16) and second coil conductor (17) with spiral shapes. Second coil (13) includes third coil conductor (18) and fourth coil conductor (19) with spiral shapes. First coil conductor (16), third coil conductor (18), second coil conductor (17), and fourth coil conductor (19) are placed in this order from above. First metal layer (14) configured to be connected to a ground is provided above first coil conductor (16).

A common mode choke comprising a first planar coil for receiving a first signal, a second planar coil for receiving a second signal, the first and second coils comprising substantially mirror images of one another and arranged side by side in a common plane, the first planar coil and second planar coil electromagnetically coupled by a closed coupling loop.

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 first coil winding and a second coil winding. The wrapping method for a common mode inductor includes steps of: disposing two isolation blocking sheets at different positions of a magnetic core; wrapping the first coil winding around the magnetic core, wherein the first coil winding is divided into two wrapping areas by one of the isolation blocking sheets; wrapping the second coil winding around the magnetic core, wherein the second coil winding is divided into two wrapping areas by the other one of the isolation blocking sheets, wherein the first coil winding and the second coil winding are symmetrically wrapped.

Methods and apparatus for capacitively isolated first communication channels with common mode noise suppression. In embodiments, a driver on the first circuit transmits a data signal on the first communication channel to a receiver on the second circuit. A common mode suppression circuit on the second circuit is coupled to the receiver, output of the suppression circuit is coupled to a node between the first capacitor and the resistor network and an input is coupled to a ground of the first circuit via a second capacitor. The common mode suppression circuit is configured to detect a common mode movement signal due to a noise pulse to the second circuit on the input and generate a corresponding signal on the output to maintain a current level across the resistor network for suppressing common mode noise from the pulse.

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.

The invention discloses a power noise suppression circuit applied to a power system. The power noise suppression circuit comprises at least one power noise to heat converter and at least one anti-power noise transmitted unit. When a power noise within a specific frequency band enters the power noise suppression circuit, the power noise to heat converter converts the power noise to a thermal energy, and the anti-power noise transmitted unit reflects the power noise within the specific frequency band to the power noise to heat converter. Accordingly, the power noise within the specific frequency band can be suppressed and absorbed in the power noise suppression circuit, so as to maintain the stability of the power system.

A common mode and a differential mode filter(s) between DC links are provided. Each link has a positive rail and a negative rail. The filter comprises a first inductor respectively connected to each of the positive rail and the negative rail, differential mode damping resistance connected in parallel to each of the first inductor, respectively, and a three-wire choke. The three-wire choke comprises a first wire connected in series with the differential mode damping resistance parallel to the positive rail, a second wire connected in series with the differential mode damping resistance parallel to the negative rail and a third wire connected to common mode damping resistance. The common mode damping resistance is galvanically isolated from differential mode transients flowing through the differential mode damping resistance. The differential mode filter has the differential mode damping resistance, and the common mode filter has the common mode damping resistance.

An LC filter that is able to obtain high insertion loss in a high-frequency band. The LC filter includes: a core including a core portion and a pair of flange portions formed at both sides of the core portion; a winding; and a pair of signal outer electrodes. At least one of the pair of flange portions is composed of a multilayer body in which inner electrodes and dielectric layers are alternately laminated, and includes a ground outer electrode. The inner electrodes include a first inner electrode and a second inner electrode alternately arranged. The first inner electrode is connected to the signal outer electrode, and the second inner electrode is connected to the ground outer electrode.

Various techniques are described to terminate a differential wire pair using combinations of CMCs, transformers, autotransformers, differential mode chokes (DMCs), and AC-coupling capacitors. The techniques improve the AC common mode insertion loss without attenuating the differential data signals, while easing the requirements of the CMC. In one example, an autotransformer, having a first winding, a second winding, and a center tap, is connected across a PHY, where the center tap provides a low impedance to ground for attenuating common mode noise. A CMC is coupled across the autotransformer and a pair of wires carrying differential data, where the CMC greatly attenuates common mode noise. The requirements of the CMC are reduced due to the autotransformer.

The present invention provides an electromagnetic interference suppression circuit including an isolation module, a transient high voltage suppression module, a common mode rejection module, and a filter module. The isolation module electrically isolates first signals to generate second signals. The transient high voltage suppression module protects the second signals against overvoltage spikes. The common mode rejection module protects the second signals against common mode noise. The filter module filters noise of the second signals, and protects the second signals against signal reflection at output terminals of the electromagnetic interference suppression circuit. The present invention further provides an electric vehicle including the electromagnetic interference suppression circuit.