Active EMI (Electro-Magnetic Interference) filter and power management device

A filter and band-pass filtering technology, which is applied in the electronic field, can solve problems such as the limitation of low-frequency noise signal filtering effect, achieve the effect of increasing impedance, enhancing filtering effect, and avoiding electromagnetic interference

Active Publication Date: 2014-12-10
HUAWEI TECH CO LTD
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

The disadvantage of this scheme is that it is difficult for the low-frequency noise signal to flow from the power supply line with high ground impedance to the power supply line with low ground impedance through the differential mode capacitor, resulting in the low-frequency noise signal on the power supply line with high ground impedance Filtering effect is limited

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  • Active EMI (Electro-Magnetic Interference) filter and power management device
  • Active EMI (Electro-Magnetic Interference) filter and power management device
  • Active EMI (Electro-Magnetic Interference) filter and power management device

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Embodiment Construction

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0042] see figure 1 , is a schematic structural composition diagram of an embodiment of the active EMI filter provided by the present invention. Such as figure 1 As shown, the active EMI filter includes an auxiliary source circuit 11, a current detection circuit 12, an inverting amplifier circuit 13, a noise injection circuit 14, a first differential mode capacitor Cd1, and a first differential mode inductor Ld1, wherein:

[0043] The first input end of the auxil...

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Abstract

The embodiment of the invention discloses an active EMI (Electro-Magnetic Interference) filter. The active EMI filter comprises an auxiliary source circuit, a current detection circuit, an inverse amplifying circuit, a noise injection circuit, a differential mode capacitor and a differential mode inductor, wherein the earth impedance of a positive power line and the earth impedance of a negative power line are different; the differential mode capacitor is connected between the positive power line and the negative power line; the differential mode inductor is connected on the power line with higher earth impedance in the positive power line and the negative power line; one end of the differential mode inductor is connected to the connected node of the auxiliary source circuit and the power line, and the other end of the differential mode inductor is connected to the connected node of the differential mode capacitor and the power line. The differential mode capacitor can enlarge the impedance for the power line with higher earth impedance, so that more low-frequency common-mode noise circuits are merged to the power line with lower earth impedance through the differential mode capacitor. The embodiment of the invention further discloses a power management device, and the power management device comprises the active EMI filter. Through the adoption of the active EMI filter and the power management device, the filtering effect for low-frequency common-mode noise current can be enhanced, and the stability of the active EMI filter is improved.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to an active EMI filter and a power management device. Background technique [0002] Generally speaking, an active EMI filter includes an auxiliary source circuit, a current detection circuit, an amplifier circuit, a noise injection circuit, and a differential-mode capacitor connected in series between the positive and negative power supply lines. Usually, the common-mode capacitance on the positive and negative power supply lines Before the noise signal is transmitted to the auxiliary source circuit, it will be joined to the power supply line with low impedance to ground through the differential mode capacitor, and then transmitted to the low impedance path of the auxiliary source circuit, the ground terminal of the amplifier circuit, and the noise injection circuit in turn. The disadvantage of this scheme is that it is difficult for the low-frequency noise signal to flow from ...

Claims

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Application Information

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IPC IPC(8): H03H11/04
Inventor 裴昌盛朱勇发骆孝龙
Owner HUAWEI TECH CO LTD
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