CN210120484U

CN210120484U - EMC filter circuit

Info

Publication number: CN210120484U
Application number: CN201920858925.8U
Authority: CN
Inventors: 刘助伟
Original assignee: Zhuhai Time Source Optoelectronic Technology Co Ltd
Current assignee: Zhuhai Time Source Optoelectronic Technology Co Ltd
Priority date: 2019-06-06
Filing date: 2019-06-06
Publication date: 2020-02-28
Anticipated expiration: 2029-06-06

Abstract

The utility model discloses an EMC filter circuit, include: the circuit comprises a first common-mode inductor, a second common-mode inductor, a first resistor, a first capacitor, a rectifier bridge, a second resistor, a third resistor, a first inductor, a second capacitor and a third capacitor; the input end of the first common-mode inductor is connected to a power supply, and the output end of the first common-mode inductor is connected to a first capacitor and a first resistor which are connected in parallel; the input end of the rectifier bridge is connected to the first resistor, and the output end of the rectifier bridge is connected to the anode of the second capacitor; the second resistor is connected with the first inductor in parallel to form a first branch circuit, the third resistor is connected with the second inductor in parallel to form a second branch circuit, and the first branch circuit is connected to the second branch circuit through a second capacitor and a third capacitor respectively; the input terminal of the second common mode inductor is connected to the third capacitor. The utility model discloses can the electromagnetic interference that the filtering power introduced and realize the rectification output, have good filtering effect, can reach EMC national standard, ensure the power consumption safety of power supply device effectively.

Description

EMC filter circuit

Technical Field

The utility model belongs to the technical field of the filtering technique and specifically relates to an EMC filter circuit.

Background

Electromagnetic Compatibility (EMC) means that in the same electromagnetic environment, a device can not affect normal operation due to interference of other devices, and meanwhile, interference affecting operation is not generated on other devices. With the rapid development of the industrial society, more and more electronic devices are provided in the families of ordinary users, and the EMC requirements on the electronic devices are higher and higher. At present, part of electronic equipment directly supplies power to each circuit of the rear stage through a power supply, which introduces a large amount of external electromagnetic interference, easily influences the working state of devices in each circuit of the rear stage, and does not accord with the national standard of related EMC.

SUMMERY OF THE UTILITY MODEL

In order to solve the problem, the utility model aims at providing an EMC filter circuit can the electromagnetic interference that the filtering power introduced, reaches EMC's national standard, ensures the power consumption safety of power supply device.

In order to compensate the deficiency of the prior art, the embodiment of the utility model provides an adopt technical scheme is:

an EMC filter circuit, comprising:

the circuit comprises a first common-mode inductor, a second common-mode inductor, a first resistor, a first capacitor, a rectifier bridge and a filter circuit; the filter circuit comprises a second resistor, a third resistor, a first inductor, a second capacitor and a third capacitor;

the input end of the first common-mode inductor is connected to a power supply, and the output end of the first common-mode inductor is connected to the first capacitor and the first resistor which are connected in parallel; the input end of the rectifier bridge is connected to the first resistor, and the output end of the rectifier bridge is connected to the anode of the second capacitor; the second resistor is connected with the first inductor in parallel to form a first branch circuit, the third resistor is connected with the second inductor in parallel to form a second branch circuit, and the first branch circuit is connected to the second branch circuit through the second capacitor and the third capacitor respectively; the input end of the second common mode inductor is connected to the third capacitor.

Further, the present technical solution further includes a fourth capacitor, where the fourth capacitor is connected to an output end of the second common mode inductor.

Furthermore, the technical scheme also comprises a safety resistor, wherein the safety resistor is connected between the input end of the first common mode inductor and a power supply.

Further, the second capacitor and the third capacitor both adopt electrolytic capacitors.

Further, the second resistor and the third resistor are both piezoresistors.

Further, the rectifier bridge adopts a KBP210 chip.

The embodiment of the utility model provides an in one or more technical scheme, following beneficial effect has at least: electromagnetic interference introduced by a power supply is filtered based on the filter circuit, and common-mode signals are filtered twice by utilizing the first common-mode inductor and the second common-mode inductor, so that the overall filtering effect is further improved; adopt the rectifier bridge to realize the rectification output for output is more reliable and more stable, and first resistance plays the effect of providing rectification voltage for the rectifier bridge, and first electric capacity plays the coupling effect. Therefore, the utility model discloses can the electromagnetic interference that the filtering power introduced and realize the rectification output, have good filtering effect, can reach EMC national standard, ensure the power consumption safety of power supply device effectively.

Drawings

The following description of the preferred embodiments of the present invention will be made with reference to the accompanying drawings.

Fig. 1 is the embodiment of the utility model provides an EMC filter circuit's circuit schematic diagram.

Detailed Description

This section will describe in detail the embodiments of the present invention, preferred embodiments of the present invention are shown in the attached drawings, which are used to supplement the description of the text part of the specification with figures, so that one can intuitively and vividly understand each technical feature and the whole technical solution of the present invention, but they cannot be understood as the limitation of the protection scope of the present invention.

In the description of the present invention, it should be understood that the orientation or positional relationship indicated with respect to the orientation description, such as up, down, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, a plurality of means are one or more, a plurality of means are two or more, and the terms greater than, less than, exceeding, etc. are understood as not including the number, and the terms greater than, less than, within, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present invention, unless there is an explicit limitation, the words such as setting, installation, connection, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in combination with the specific contents of the technical solution.

The embodiments of the present invention will be further explained with reference to the drawings.

Referring to fig. 1, an embodiment of the present invention provides an EMC filter circuit 100, including:

the circuit comprises a first common-mode inductor LF1, a second common-mode inductor LF2, a first resistor RX1, a first capacitor CX1, a rectifier bridge DB1 and a filter circuit 100; the filter circuit 100 comprises a second resistor RL1, a third resistor RL2, a first inductor L1, a second inductor L2, a second capacitor CX3 and a third capacitor CX 4;

the input end of the first common-mode inductor LF1 is connected to a power supply, and the output end of the first common-mode inductor LF1 is connected to the first capacitor CX1 and the first resistor RX1 connected in parallel; the input end of the rectifier bridge DB1 is connected to the first resistor RX1, and the output end of the rectifier bridge DB1 is connected to the positive electrode of the second capacitor CX 3; the second resistor RL1 is connected in parallel with the first inductor L1 to form a first branch 101, the third resistor RL2 is connected in parallel with the second inductor L2 to form a second branch 102, and the first branch 101 is connected to the second branch 102 through the second capacitor CX3 and the third capacitor CX4 respectively; the input terminal of the second common mode inductor LF2 is connected to the third capacitance CX 4.

In this embodiment, the electromagnetic interference introduced by the power supply is filtered based on the filter circuit 100, and the common-mode signal is filtered twice by using the first common-mode inductor LF1 and the second common-mode inductor LF2, so that the overall filtering effect is further improved; adopt rectifier bridge DB1 to realize the rectification output for output is more reliable and more stable, and first resistance RX1 plays the effect of providing the rectified voltage for rectifier bridge DB1, and first electric capacity CX1 plays the coupling effect. Therefore, the embodiment can filter electromagnetic interference introduced by the power supply and realize rectification output, has a good filtering effect, can reach the EMC national standard, and effectively guarantees the power utilization safety of power supply devices.

Specifically, the second resistor RL1 and the third resistor RL2 are differential mode resistors, and cooperate with the first inductor L1, the second inductor L2, the second capacitor CX3 and the third capacitor CX4 to suppress differential mode signals at low frequencies, wherein the first inductor L1 and the second inductor L2 are differential mode inductors and mainly play a role in isolating alternating current filtering, and the second capacitor CX3 and the third capacitor CX4 mainly play a role in coupling the first branch circuit 101 and the second branch circuit 102; the first common-mode inductor LF1 and the second common-mode inductor LF2 mainly play a role in filtering common-mode signals, have a certain limiting effect on high-frequency noise, and have a good filtering effect when combined; the output end of the second common-mode inductor LF2 is connected to a post-stage circuit to supply power to the post-stage circuit, and the post-stage circuit is a driving end of an electronic device (for example, driving circuits such as an LED, an induction cooker, and an oven, which are not described herein); the first capacitance CX1 also plays a role in isolating ac interference based on coupling.

Further, the present invention provides an EMC filter circuit 100, wherein the EMC filter circuit further includes a fourth capacitor CX2, and the fourth capacitor CX2 is connected to the output end of the second common mode inductor LF 2. In this embodiment, the fourth capacitor CX2 is disposed behind the output end of the second common mode inductor LF2, so as to further filter the output, and the ac component in the output current passing through the fourth capacitor CX2 is further reduced, so that the output voltage component is more stable and reliable.

Further, another embodiment of the present invention further provides an EMC filter circuit 100, wherein, further includes a safety resistor F1, the safety resistor F1 is connected between the input end of the first common mode inductor LF1 and the power supply. In the embodiment, the fuse resistor F1 is used to interrupt the power supply of the power supply when the temperature is over, so as to protect the electronic device.

Further, the present invention further provides an EMC filter circuit 100, wherein the second capacitor CX3 and the third capacitor CX4 both adopt electrolytic capacitors. In this embodiment, the electrolytic capacitors have a better coupling function, so that the coupling connection between the first branch 101 and the second branch 102 is more stable, and preferably, the anodes of the two electrolytic capacitors are both connected to the first branch 101.

Further, another embodiment of the present invention further provides an EMC filter circuit 100, wherein the second resistor RL1 and the third resistor RL2 both use voltage dependent resistors. In this embodiment, the voltage dependent resistor is a voltage limiting type protection device, and when overvoltage turn-on occurs, the voltage dependent resistor can clamp the voltage to a steady state value, so as to protect the rear output.

Further, another embodiment of the present invention further provides an EMC filter circuit 100, wherein the rectifier bridge DB1 adopts a KBP210 chip. In this embodiment, the KBP210 chip is used as a core piece of the rectifier bridge DB1, and has stable performance and convenient triggering, and can also be replaced by a bridge chip with similar functions, which is not described herein again.

While the preferred embodiment and basic principles of the present invention have been described in detail, it will be understood by those skilled in the art that the invention is not limited to the embodiments disclosed, but is intended to cover various modifications, equivalents and alternatives falling within the scope of the invention as claimed.

Claims

1. An EMC filter circuit, comprising:

2. The EMC filter circuit of claim 1, wherein: and the fourth capacitor is connected to the output end of the second common mode inductor.

3. The EMC filter circuit of claim 1, wherein: the protection circuit further comprises a safety resistor, and the safety resistor is connected between the input end of the first common mode inductor and a power supply.

4. The EMC filter circuit of claim 1, wherein: and the second capacitor and the third capacitor both adopt electrolytic capacitors.

5. The EMC filter circuit of claim 1, wherein: and the second resistor and the third resistor are both piezoresistors.

6. The EMC filter circuit of claim 1, wherein: the rectifier bridge adopts a KBP210 chip.