CN2785228Y - Power supply noise filter based on electromagnetic compatibility - Google Patents

Abstract

A power supply noise filter based on electromagnetic compatibility design belonging to the technical field of electronic applications includes four common-mode inductance coils, a resistor, a differential-mode noise suppression circuit and two common-mode capacitors; the differential-mode noise suppression circuit includes differential-mode capacitors and Two differential mode inductance coils; the utility model is a four-way passive network, which can simultaneously suppress the common mode noise which is the main component in the high frequency domain and the differential mode noise which is the main component in the low frequency domain, and insert it into the AC grid Between it and the power supply, it is equivalent to adding a blocking barrier between the electromagnetic interference noise of the two, which plays the role of bidirectional suppression of electromagnetic interference noise, and can be applied to various electronic devices.

Description

Power supply noise filter based on electromagnetic compatibility

technical field

The utility model belongs to the technical field of electronic applications and relates to a power supply noise filter circuit, in particular to a power supply noise filter based on electromagnetic compatibility.

technical background

With the rapid development of modern science and technology, the application of electronics, power electronics, and electrical equipment is becoming more and more extensive. The high-density, wide-spectrum electromagnetic signals generated during their operation fill the entire space and form a complex electromagnetic environment. The complex electromagnetic environment requires electronic equipment and power supplies to have higher electromagnetic compatibility, so more and more attention has been paid to the technology of suppressing electromagnetic interference.

As we all know, there are two kinds of electromagnetic interference noise on the input leads of power equipment: common mode noise and differential mode noise. The electromagnetic interference noise existing between the AC input leads and the ground is common mode noise, and the electromagnetic interference noise existing between the AC input leads is differential mode noise. At present, the suppression measures taken for electromagnetic interference noise are mainly to suppress common-mode noise and ignore differential-mode noise. The circuit is shown in Figure 1, which includes common-mode inductor coil 1, common-mode inductor coil 2, resistor 5, Capacitors 10 and 11.

Contents of the invention

The utility model is a four-way passive network, which adopts the measures of simultaneously suppressing the common-mode noise in the whole frequency domain, especially the high-frequency domain and the differential-mode noise in the low-frequency domain, so that the alternating current can be transmitted without attenuation. to the power supply equipment, and attenuate the electromagnetic interference noise introduced by the alternating current, and at the same time, it can effectively suppress the electromagnetic interference noise generated by the power supply equipment. The purpose is to provide a power supply noise filter based on electromagnetic compatibility.

The utility model is a four-terminal passive network composed of concentrated parameter elements, which includes common-mode inductance coils 1, 2, 3 and 4, a resistor 5, a differential-mode noise suppression circuit 6, and common-mode capacitors 10 and 11. One end input lead wire of the utility model is sequentially connected with one end input lead wire of the common mode inductor coil 1, the common mode inductor coil 3 and the differential mode noise suppression circuit 6, and the other end input lead wire of the utility model is connected with the common mode inductor coil 2, the common mode inductor coil 4 and the other end of the differential mode noise suppression circuit 6 are connected in sequence, one end of the resistor 5 is connected to the common node of the common mode inductance coil 3 and the differential mode noise suppression circuit 6, and the other end of the resistor 5 is connected to the common mode inductance coil 4 and the differential mode The common node of the noise suppression circuit 6 is connected. The common-mode capacitors 10 and 11 are connected in series, and connected across the two output leads of the differential-mode noise suppression circuit 6, that is, between the two output ends of the utility model, and the common contact of the common-mode capacitors 10 and 11 is grounded.

The differential mode noise suppression circuit 6 includes a differential mode capacitor 7, a differential mode inductance coil 8 and 9; one end of the differential mode capacitor 7 is connected to the common junction of the differential mode inductance coil 8, the common mode inductance coil 3 and the resistor 5, and the differential mode capacitor 7 The other end of the differential mode inductance coil 9, the common mode inductance coil 4 and the common junction of the resistance 5 are connected; the output end of the differential mode inductance coil 8 is connected with the common mode capacitor 10; the output end of the differential mode inductance coil 9 is connected with the common mode capacitor 11 .

Working process of the utility model: the utility model is placed on the input end of the power supply, and the common mode inductance coil 1, the common mode inductance coil 3, and the common mode capacitor 10 form a low-pass filter between the independent ports on the AC incoming line. Mode inductance coil 2, common mode inductance coil 4, and common mode capacitor 11 form a low-pass filter between another independent port on the AC incoming line, which can attenuate the common mode interference noise existing on the AC incoming line and prevent them from entering the power supply equipment . The differential mode noise suppression circuit 6 composed of the differential mode capacitor 7 and the differential mode inductors 8 and 9 is a low-pass filter between the independent ports of the AC incoming line, which is used to suppress the differential mode interference signal on the AC incoming line and prevent the power supply equipment from being affected by it. Interference, resistor 5 acts as a heat sink.

The utility model is a passive network, which can simultaneously suppress the common-mode noise in the high-frequency domain and the differential-mode noise in the low-frequency domain. A blocking barrier is added between the electromagnetic interference noise of the former, which plays a role in suppressing electromagnetic interference noise in both directions, and can be applied to various electronic devices.

Description of drawings

Fig. 1 is the utility model circuit diagram, also is the accompanying drawing of description abstract. 1, 2, 3, and 4 in the figure are common-mode inductance coils, 5 resistors, 6 differential-mode noise suppression circuits, 7 differential-mode capacitors, 8 and 9 differential-mode inductors, and 10 and 11 common-mode capacitors.

Detailed ways

The utility model comprises common-mode inductance coils 1, 2, 3 and 4, a resistor 5, a differential-mode noise suppression circuit 6, and common-mode capacitors 10 and 11. Among them, the common mode inductance coils 1 and 2 are coils with the same number of turns wound on a closed magnetic circuit ferrite in the same direction, and the common mode inductive coils 3 and 4 are also wound in the same direction on a closed magnetic circuit ferrite. turns of the coil. Common mode inductance coils 1, 2, 3 and 4 use inductance coils with a magnetic flux of 20mH, resistor 5 uses a resistor with a resistance value of 1K, and common mode capacitors 10 and 11 use monolithic capacitors with a capacity of less than 0.01 μF.

The differential-mode noise suppression circuit 6 includes a differential-mode capacitor 7, differential-mode inductors 8 and 9, wherein the differential-mode capacitor 7 is a monolithic capacitor with a capacity of 0.1 μF to 0.47 μF, and the differential-mode inductors 8 and 9 are selected with a magnetic flux of 0.01 mH induction coil.

Claims (2)

1. A power supply noise filter based on electromagnetic compatibility, comprising common-mode inductance (1), common-mode inductance (2), resistance (5), common-mode capacitance (10) and (11), is characterized in that It also includes a common mode inductor (3), a common mode inductor (4), a differential mode noise suppression circuit (6); one end of the input lead is connected to the common mode inductor (1), the common mode inductor (3) and the differential mode noise The input leads at one end of the suppression circuit (6) are sequentially connected, the input leads at the other end are sequentially connected with the input leads at the other end of the common mode inductance coil (2), the common mode inductance coil (4) and the differential mode noise suppression circuit (6), and the resistance ( One end of 5) is connected to the common joint of the common-mode inductance coil (3) and the differential-mode noise suppression circuit (6), and the other end of the resistor (5) is connected to the public joint of the common-mode inductance coil (4) and the differential-mode noise suppression circuit (6). The joints are connected; the common-mode capacitors (10) and (11) are connected in series, and across the two output leads of the differential-mode noise suppression circuit (6), that is, between the two output terminals, the common-mode capacitors (10) and (11) The common contact is grounded. 2. The power supply noise filter designed based on electromagnetic compatibility according to claim 1 is characterized in that the differential mode noise suppression circuit (6) comprises a differential mode capacitor (7), a differential mode inductance (8) and (9), and the differential mode One end of the mode capacitor (7) is connected to the common junction of the differential mode inductance coil (8), the common mode inductance coil (3) and the resistor (5), and the other end of the differential mode capacitor (7) is connected to the differential mode inductance coil (9) , the common mode inductance coil (4) is connected with the public joint of resistance (5); the output end of differential mode inductance coil (8) is connected with common mode capacitor (10); the output end of differential mode inductance coil (9) is connected with common mode capacitor ( 11) Connected.