CN205195553U - Emi filter circuit - Google Patents
Emi filter circuit Download PDFInfo
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- CN205195553U CN205195553U CN201520812486.9U CN201520812486U CN205195553U CN 205195553 U CN205195553 U CN 205195553U CN 201520812486 U CN201520812486 U CN 201520812486U CN 205195553 U CN205195553 U CN 205195553U
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- common mode
- diode
- filter circuit
- inductance
- emi filter
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Abstract
The utility model relates to a EMI filter circuit. A EMI filter circuit, includes common mode inductance, differs from common mode filter unit and rectifier unit, common mode inductance includes the magnetic core, winds two coils and follow on the magnetic core two four terminals that the coil was drawn forth, poor common mode filter circuit common mode inductance rectifier circuit connect gradually the back with the load is connected, common mode inductance's input still is connected with live wire, the zero line of outside electric wire netting respectively. Among the above -mentioned EMI filter circuit, replace traditional two -stage inductance through a common mode inductance, undertake the noise filtering of low -frequency range and high band simultaneously, realize height, low frequency filter's effect. Adopt common mode inductance simultaneously can also reduce cost, improve production efficiency.
Description
Technical field
The utility model relates to electron electric power filter circuit technical field, particularly relates to EMI filter circuit.
Background technology
Due to power semiconductor, as IGBT, diode, thyristor etc., and these devices are all operated on off state, very high dv/dt and di/dt can be produced, produce abundant harmonic component interference noise, and then form differential mode interference and common mode disturbances, i.e. electromagnetic interference (ElectromagneticInterference, EMI).
In order to eliminate electromagnetic interference, traditional EMI filter circuit forms primarily of two-stage inductance (the first inductance L F1, the second inductance L F2), X electric capacity and Y capacitance, wherein the first inductance: coiling one deck forms, interlayer equivalent capacity is minimum, high-frequency resistance is large, the few sensibility reciprocal of the number of turns is little, bears High frequency filter effect; Second inductance is repeatedly formed by enameled wire loop lap wound, and interlayer equivalent capacity is very big, and the many sensibility reciprocals of the number of turns are large, and layer capacitance is large, and high-frequency resistance is little, bears low frequency filtering and uses.But the cost of this two-stage inductance is high and filter circuit volume can be caused excessive, is unfavorable for realizing circuit Miniaturization Design.
Utility model content
Based on this, be necessary that cost for two-stage inductance is high and filter circuit volume can be caused excessive, be unfavorable for realizing circuit Miniaturization Design problem, a kind of EMI filter circuit is provided.
A kind of EMI filter circuit, comprise common mode inductance, difference common mode filtering unit and rectification unit, described common mode inductance comprises magnetic core, around the coil of two on described magnetic core and four terminals from described two coils extraction, be connected with described load after described poor common mode filtering circuit, described common mode inductance, described rectification circuit connect successively, the input of described common mode inductance is also connected with the live wire of external electrical network, zero line respectively.
Wherein in an embodiment, described poor common mode filtering unit comprises differential mode capacitor, the first common mode capacitance and the second common mode capacitance, the two ends of described differential mode capacitor are connected with the live wire of external electrical network, zero line respectively, described first common mode capacitance is in parallel with described differential mode capacitor after connecting with the second common mode capacitance, the common end grounding of described first common mode capacitance and the second common mode capacitance, described first common mode capacitance, second unearthed one end of common mode capacitance are connected with the first end of common mode inductance, the second end respectively.
Wherein in an embodiment, described rectification unit comprises the first diode, the second diode, the 3rd diode, the 4th diode and electrochemical capacitor, the negative electrode of described first diode is connected with the anode of the 4th diode, the negative electrode of the second diode is connected with the anode of the 3rd diode, the anode of the first diode, the second diode is all connected with the first end of electrochemical capacitor, the negative electrode of the 3rd diode, the 4th diode is all connected with the second end of electrochemical capacitor, and the two ends of electrochemical capacitor are connected with load respectively.
Wherein in an embodiment, described EMI filter circuit also comprises fuse, and the first end of described fuse connects the live wire of external electrical network, and the second end of described fuse is connected with one end of described common mode capacitance.
Wherein in an embodiment, coil dimension is identical, the number of turn is identical, coiling direction is identical for two of described common mode inductance.
Wherein in an embodiment, the magnetic core of described common mode inductance is ferrite toroidal magnetic core, and described coil is insulated conductor, and individual layer is around on magnetic core.
Wherein in an embodiment, between described magnetic core and coil, there is insulating barrier.
Wherein in an embodiment, described common mode inductance is adjustable inductance, and described sensibility reciprocal scope is 5 milihenry ~ 20 milihenries.
Wherein in an embodiment, described differential mode capacitor is metallized film capacitor, the first common mode capacitance and the second common mode capacitance are ceramic disc capacitor.
In above-mentioned EMI filter circuit, traditional two-stage inductance is replaced by a common mode inductance, bear the noise filtering of low-frequency range (150KHZ to 5MHZ noise filtering) and high band (5MHZ to 30MHZ) simultaneously, realize the effect of high and low frequency filtering.The common mode inductance adopted can also reduce costs simultaneously, enhance productivity.
Accompanying drawing explanation
Fig. 1 is EMI filter circuit figure.
Embodiment
For the ease of understanding the utility model, below with reference to relevant drawings, the utility model is described more fully.Preferred embodiment of the present utility model is given in accompanying drawing.But the utility model can realize in many different forms, is not limited to embodiment described herein.On the contrary, provide the object of these embodiments be make the understanding of disclosure of the present utility model more comprehensively thorough.
Unless otherwise defined, all technology used herein and scientific terminology are identical with belonging to the implication that those skilled in the art of the present utility model understand usually.The object of the term used in specification of the present utility model herein just in order to describe specific embodiment, is not intended to limit the utility model.Term as used herein "and/or" comprises arbitrary and all combinations of one or more relevant Listed Items.
As shown in Figure 1 be EMI filter circuit, EMI filter circuit comprises poor common mode filtering unit 100, common mode inductance LF, rectification unit 200, difference common mode filtering circuit 100, common mode inductance LF, rectification circuit 200 are connected with load after connecting successively, wherein, common mode inductance LF comprises magnetic core, around the coil of two on described magnetic core and four terminals (1 from two coils extractions, 2,3,4), first end 1, second end 2 of common mode inductance LF is also connected with live wire L, the zero line N of external electrical network respectively; 3rd end 3, the 4th end 4 of common mode inductance LF are also connected with load.
Two coil L1 with L2 of common mode inductance LF measure-alike, the number of turn is identical, coiling direction is identical.In the present embodiment, the magnetic core of common mode inductance LF is ferrite toroidal magnetic core, and coil is insulated conductor, and two coil L1 and L2 are all with the efficient coiling of machine, and individual layer around on magnetic core, and has a layer insulating between magnetic core and coil.Coil winding number in common mode inductance LF is 50 circles, is around once forming by enamel-cover flat copper wire zero lap.Owing to adopting machine winding, easy for installation, technique for coiling can better control.The many sensibility reciprocals of the number of turns are large, and electric capacity is minimum, and according to 1/wc=1/2 л fc, high frequency presents Low ESR, and low-and high-frequency impedance is large.Thus achieve a common mode inductance LF and replace traditional two-stage inductance, bear the noise filtering of low-frequency range (150KHZ to 5MHZ noise filtering) and high band (5MHZ to 30MHZ) simultaneously, realize the effect of high and low frequency filtering.Adopt a common mode inductance to reach the efficiency that can also reduce costs, enhance productivity simultaneously.
Common mode inductance LF is adjustable inductance, and inductance value scope is 5 milihenry ~ 20 milihenries (mh).
With reference to figure 1, difference common mode filtering unit 100 comprises differential mode capacitor CX, the first common mode capacitance CY1 and the second common mode capacitance CY2, the two ends of differential mode capacitor CX are connected with live wire L, the zero line N of external electrical network respectively, it is in parallel with differential mode capacitor CX after first common mode capacitance CY1 connects with the second common mode capacitance CY2, the common end grounding of the first common mode capacitance CY1 and the second common mode capacitance CY2, first common mode capacitance CY1 one end, second common mode capacitance CY2 one end are connected with first end 1, second end 2 of common mode inductance L F respectively.In the present embodiment, differential mode capacitor CX is metallized film capacitor, and common mode capacitance (CY1, CY2) is ceramic disc capacitor.The capacitance value range of differential mode capacitor CX is: 0.22 μ F ~ 0.47 μ F, the capacitance value range of first and second common mode capacitance (CY1, CY2) is: 100pF ~ 1nF.The capacitance of each electric capacity can be regulated according to the situation of load.Load can be Switching Power Supply circuit, and namely load equivalent produces the noise jamming of 150KZH to 30MHZ.
Rectification unit 200 is for being rectified into direct current by the electric main of external electrical network.
Rectification unit 200 comprises the first diode D1, the second diode D2, the 3rd diode D3, the 4th diode D4 and electrochemical capacitor EC, the negative electrode of the first diode D1 is connected with the anode of the 4th diode D4, the negative electrode of the second diode D2 is connected with the anode of the 3rd diode D3, the anode of the first diode D1, the second diode D2 is all connected with the first end of electrochemical capacitor EC, the negative electrode of the 3rd diode D3, the 4th diode D4 is all connected with second end of electrochemical capacitor EC, and the two ends of electrochemical capacitor EC are connected with load respectively.
EMI filter circuit also comprises fuse F, and the first end of fuse F connects the live wire L of external electrical network, and second end of fuse F1 is connected with one end of common mode capacitance CX.When the electric current flowing through fuse F exceedes preset value, the heat that fuse F self produces makes melt fuse, thus circuit is disconnected, and makes electric current protected.
Further, when the normal current in circuit flows through common mode inductance, electric current produces reverse magnetic field and cancels out each other in the inductance coil of same-phase coiling, and now normal signal electric current is mainly subject to the impact (with a small amount of damping caused because of leakage inductance) of common mode inductance LF coil resistance; When flowing through the electric current having differential mode interference in circuit, differential mode capacitor CX will suppress differential mode interference, and decay differential-mode current, reaches the effect of filtering; When flowing through the electric current having common mode disturbances in circuit, first common mode capacitance CY1 and the second common mode capacitance CY2 also can suppress common mode disturbances, magnetic field in the same way can be produced in the coil of common mode inductance LF simultaneously and increase the induction reactance of coil, coil is made to show as high impedance, produce stronger damping, with this attenuation common-mode electric current, reach the object of filtering.
Each technical characteristic of the above embodiment can combine arbitrarily, for making description succinct, the all possible combination of each technical characteristic in above-described embodiment is not all described, but, as long as the combination of these technical characteristics does not exist contradiction, be all considered to be the scope that this specification is recorded.
The above embodiment only have expressed several execution mode of the present utility model, and it describes comparatively concrete and detailed, but therefore can not be interpreted as the restriction to utility model patent scope.It should be pointed out that for the person of ordinary skill of the art, without departing from the concept of the premise utility, can also make some distortion and improvement, these all belong to protection range of the present utility model.Therefore, the protection range of the utility model patent should be as the criterion with claims.
Claims (9)
1. an EMI filter circuit, comprise common mode inductance, difference common mode filtering unit and rectification unit, described common mode inductance comprises magnetic core, around the coil of two on described magnetic core and four terminals from described two coils extraction, it is characterized in that, be connected with load after described poor common mode filtering circuit, described common mode inductance, described rectification circuit connect successively, the input of described common mode inductance is connected with the live wire of external electrical network, zero line respectively.
2. EMI filter circuit according to claim 1, it is characterized in that, described poor common mode filtering unit comprises differential mode capacitor, the first common mode capacitance and the second common mode capacitance, the two ends of described differential mode capacitor are connected with the live wire of external electrical network, zero line respectively, described first common mode capacitance is in parallel with described differential mode capacitor after connecting with the second common mode capacitance, the common end grounding of described first common mode capacitance and the second common mode capacitance, described first common mode capacitance, second unearthed one end of common mode capacitance are connected with the first end of common mode inductance, the second end respectively.
3. EMI filter circuit according to claim 1, it is characterized in that, described rectification unit comprises the first diode, the second diode, the 3rd diode, the 4th diode and electrochemical capacitor, the negative electrode of described first diode is connected with the anode of the 4th diode, the negative electrode of the second diode is connected with the anode of the 3rd diode, the anode of the first diode, the second diode is all connected with the first end of electrochemical capacitor, the negative electrode of the 3rd diode, the 4th diode is all connected with the second end of electrochemical capacitor, and the two ends of electrochemical capacitor are connected with load respectively.
4. EMI filter circuit according to claim 2, is characterized in that, described EMI filter circuit also comprises fuse, and the first end of described fuse connects the live wire of external electrical network, and the second end of described fuse is connected with one end of described common mode capacitance.
5. EMI filter circuit according to claim 1, is characterized in that, coil dimension is identical, the number of turn is identical, coiling direction is identical for two of described common mode inductance.
6. EMI filter circuit according to claim 1, is characterized in that, the magnetic core of described common mode inductance is ferrite toroidal magnetic core, and described coil is insulated conductor, and individual layer is around on magnetic core.
7. EMI filter circuit according to claim 6, is characterized in that, has insulating barrier between described magnetic core and coil.
8. EMI filter circuit according to claim 1, is characterized in that, described common mode inductance is adjustable inductance, and the sensibility reciprocal scope of described common mode inductance is 5 milihenry ~ 20 milihenries.
9. EMI filter circuit according to claim 2, is characterized in that, described differential mode capacitor is metallized film capacitor, the first common mode capacitance and the second common mode capacitance are ceramic disc capacitor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520812486.9U CN205195553U (en) | 2015-10-19 | 2015-10-19 | Emi filter circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520812486.9U CN205195553U (en) | 2015-10-19 | 2015-10-19 | Emi filter circuit |
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| CN205195553U true CN205195553U (en) | 2016-04-27 |
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| CN201520812486.9U Active CN205195553U (en) | 2015-10-19 | 2015-10-19 | Emi filter circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110456291A (en) * | 2019-08-28 | 2019-11-15 | 创领心律管理医疗器械（上海）有限公司 | Filter circuit and electronic device |
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2015
- 2015-10-19 CN CN201520812486.9U patent/CN205195553U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110456291A (en) * | 2019-08-28 | 2019-11-15 | 创领心律管理医疗器械（上海）有限公司 | Filter circuit and electronic device |
| CN110456291B (en) * | 2019-08-28 | 2021-12-24 | 创领心律管理医疗器械（上海）有限公司 | Filter circuit and electronic device |
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