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 harmonics suppression filter includes a main circuit, a first inner circuit, a first outer circuit, a first inner node and a first outer node. The first inner circuit, the first outer circuit and the main circuit are in the same layer of the base board. Meanwhile, the first inner circuit is located inside of the main circuit. There is an inner gap between the first inner circuit and the main circuit. The first outer circuit is located outside of the main circuit. There is an outer gap between the first outer circuit and the main circuit. The first inner node is located in the inner gap to couple the first inner circuit with the main circuit. The first outer node is located in the outer gap to couple the first outer circuit with the main circuit.

An inductor-capacitor (LC) filter designed to comply with EMC (Electromagnetic Compatibility) standards comprises capacitors; switches for coupling capacitors; differential-mode inductors for coupling capacitors and switches; and common-mode inductors or a combination of differential-mode inductors and common-mode inductors, where an input signal changes the inductance of differential-mode inductors in the LC filter to modify a frequency response of the LC filter. In the LC filter, differential-mode inductors further comprise identical multiple-winding inductors, and the input signal, which biases the plurality of differential-mode inductors, includes a DC signal or a combination of DC and AC signals. A corner-frequency of the LC filter is adjusted and approximated as: fc=1/(2pisqrt(LC)), where fc is the corner-frequency, L is a composite value of inductance, and C is a composite value of capacitance.

A novel and useful transmitter (TX) architecture for ultra-low power (ULP) radios. An all-digital PLL employs a digitally controlled oscillator (DCO) having switching current sources to reduce supply voltage and power consumption without sacrificing phase noise and startup margins. It also reduces 1/f noise allowing the ADPLL after settling to reduce its sampling rate or shut it off entirely during direct DCO data modulation. A switching power amplifier integrates its matching network while operating in class-E/F.sub.2 to maximally enhance its efficiency. The transmitter has been realized in 28 nm CMOS and satisfies all metal density and other manufacturing rules. It consumes 3.6 mW/5.5 mW while delivering 0 dBm/3 dBm RF power in Bluetooth Low-Energy.

A power supply system is disclosed that includes a first interleaved power supply, a second interleaved power supply, and a common electromagnetic interference filter. The common electromagnetic interference filter is configured to provide DC power from a DC power source to both the first interleaved power supply and the second interleaved power supply. In one example, the common electromagnetic interference filter comprises a localized filter stage configured to receive DC power from the DC power source, and a distributed filter stage configured to receive DC power from the localized filter stage. The distributed filter stage includes a first set of common mode capacitors electrically connected to and physically proximate input power lines of the first interleaved power supply, and a second set of common mode capacitors electrically connected to and physically proximate input power lines of the second interleaved power supply.

On a first-signal-line side, a first resonant circuit is defined by a first inductance element, a first capacitance element, a second capacitance element, a third inductance element and a fifth inductance element, a third resonant circuit is defined by the first inductance element, the first capacitance element and the second capacitance element, and a fifth resonant circuit is defined by the first inductance element, the third inductance element, the first capacitance element, the second capacitance element and the fifth capacitance element. Similarly, on a second-signal-line side, a second resonant circuit, a fourth resonant circuit and a sixth resonant circuit are provided.

A novel and useful transmitter (TX) architecture for ultra-low power (ULP) radios. An all-digital PLL employs a digitally controlled oscillator (DCO) having switching current sources to reduce supply voltage and power consumption without sacrificing phase noise and startup margins. It also reduces 1/f noise allowing the ADPLL after settling to reduce its sampling rate or shut it off entirely during direct DCO data modulation. A switching power amplifier integrates its matching network while operating in class-E/F.sub.2 to maximally enhance its efficiency. The transmitter has been realized in 28 nm CMOS and satisfies all metal density and other manufacturing rules. It consumes 3.6 mW/5.5 mW while delivering 0 dBm/3 dBm RF power in Bluetooth Low-Energy.

A device that filters electromagnetic interference includes electrical conductors mounted in parallel. Each conductor includes a first coil positioned between a first and a second end of the respective conductor. Each first coil is coupled magnetically to each other first coil and has the same number of turns as each other first coil. The first and second ends of each of the conductors, respectively, are first and second terminals for the device. The device includes capacitors. Each capacitor is mounted between the second end of a corresponding electrical conductor and a third terminal of the device. The device includes an additional circuit. The additional circuit includes a second coil coupled magnetically with the first coils of the conductors. The additional circuit includes an additional coil. The second coil has a second number of turns.

A common mode filter coupled to a protection device. In accordance with an embodiment, the common mode filter has first and second coils, each coil having a spiral shape, a central region, an exterior region, a first terminal, and a second terminal, wherein the first terminal of the first coil is formed in a first portion of the central region, the first terminal of the second coil is formed in a second portion of the central region, and wherein the central region is laterally bounded by the first and second coils and the exterior region is not surrounded by the first and second coils. The protection device has a first terminal coupled to the first terminal of the first coil and a second terminal coupled to the first terminal of the second coil.

A common-mode filter includes a first transmission line, a second transmission line, a first wiring layer, a second wiring layer and a third wiring layer. The first wiring layer includes a first conductive capacitor plate, in which at least partial first transmission line is in the first wiring layer, and electrically coupled with the first conductive capacitor plate. The second wiring layer includes a second conductive plate and a first inductor, and the second conductive capacitor plate is electrically coupled with the first inductor. The third wiring layer includes a third conductive capacitor plate, in which at least partial second transmission line is in the second wiring layer, and electrically coupled with the third conductive capacitor plate. The first conductive capacitor plate at least partial faces the second conductive capacitor plate, and the second conductive capacitor plate at least partial faces the third conductive capacitor plate.