CN103986437A - Double-grounded plane EMI filter - Google Patents
Double-grounded plane EMI filter Download PDFInfo
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- CN103986437A CN103986437A CN201410193132.0A CN201410193132A CN103986437A CN 103986437 A CN103986437 A CN 103986437A CN 201410193132 A CN201410193132 A CN 201410193132A CN 103986437 A CN103986437 A CN 103986437A
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Abstract
The invention discloses a double-grounded plane EMI filter. The double-grounded plane EMI filter comprises a tank type magnetic core, a panel magnetic core, an inductor unit and a capacitor unit, wherein the inductor unit and the capacitor unit are arranged between the tank type magnetic core and the panel magnetic core, an isolation base board is arranged between the inductor unit and the capacitor unit, the capacitor unit comprises a plurality of ceramic base boards which are arranged between two copper layers and sequentially connected, every two adjacent ceramic base boards are connected through a silver layer, the outer surfaces of the ceramic base boards located on the outermost side are both connected with the copper layers, and the two copper layers are both grounded. Through the structure that a capacitor structure and an integrated inductor structure are isolated and the copper layers and the silver layers are arranged, common mode capacitors and differential mode capacitors are integrated, the problem that in the prior art, an upper metal conductor and a lower metal conductor of the filter are not symmetrical, so that the filtering effect is poor is solved, symmetry of the upper metal conductor and the lower metal conductor is well improved, parasitic parameters are effectively reduced, and therefore the performance of the filter is improved.
Description
Technical field
The present invention relates to a kind of pair of ground plane electromagnetic interface filter, belong to electromagnetic interface filter field.
Background technology
Along with the high frequency of power electronics and electric power system, the development of miniaturization, electromagnetic interference problem is further outstanding.Electromagnetic interference is mainly divided into conducted interference and radiated interference, and the former mainly refers to the interference between 150kHz-30MHz, and the latter mainly refers to be greater than the interference of 30MHz, wherein conducted interference in interference problem now in the highest flight.The method of eliminating conducted interference mainly contains and eliminates noise source, cuts off coupling path and improves equipment antijamming capability etc.And electromagnetic interface filter can effectively improve the antijamming capability of equipment, thereby conducted interference is well suppressed.
The electromagnetic interface filter of discrete is in the past because element is many, volume is large, parasitic parameter is large and the poor formula electromagnetic interface filter that is integrated gradually of high frequency performance replaces.The Shi You Virginia Polytechnic Institute and State University proposition the earliest of the concept of Planar integration electromagnetic interface filter, its elementary cell is plane LC coil, is mainly used in the integrated of " inductance " and " electric capacity ".This kind of integrated morphology has realized the Planar Integrated Magnetic Structure of electromagnetic interface filter, has reduced to a certain extent volume and has increased its power density.But this kind of plane LC loop construction also just exists certain weak point,, because coil is rectangle, corner's current density is large, so CURRENT DISTRIBUTION is inhomogeneous, has a strong impact on the high frequency performance of electromagnetic interface filter.Therefore, there is team to propose on this basis planar annular electromagnetic interface filter, effectively improved the CURRENT DISTRIBUTION of lc unit each several part.This kind of filter can be placed in toroidal core completely simultaneously, greatly improved its inductance value.
Classical annular planar EMI filter as shown in Figure 1A, thereby its elementary cell be in the both sides of hard ceramic substrate respectively the even helix of spraying plating realize " LC " integrated lc unit, by suitable connected mode, generating high frequency noise is effectively suppressed.Meanwhile, the common-mode filter of such planar EMI filter is mainly comprised of two lc units, as Figure 1B, two upper and lower two coil windings one end of lc unit are input, and one end is output, and middle two coil windings one end are unsettled, altogether, its equivalent electric circuit as shown in Figure 1 C in one end.Differential mode filter is mainly by differential mode inductance and differential mode capacitor, and differential mode inductance is produced by the leakage inductance of common mode inductance, and the independent capacitance that differential mode capacitor is mainly accessed by outside is realized.Therefore, above-mentioned electromagnetic interface filter only has a place altogether, though and the planar annular electromagnetic interface filter after improving unit sheet is all integrated in toroidal core, increased inductance, the employing dislocation via hole between multi-disc lc unit connects, method is complicated, is difficult for realizing.When lc unit is realized capacitance parameter, in requirement, lower coil is as far as possible symmetrical to realize larger capacitance, and this has proposed very high requirement to the symmetry of lc unit and manufacture craft.
Summary of the invention
Technical problem to be solved by this invention is: the invention provides a kind of pair of ground plane electromagnetic interface filter, by electric capacity and integrated LC structure are kept apart, and the structure of copper layer, silver layer is set, common mode capacitance and differential mode capacitor are integrated in one, have solved the poor problem of the asymmetric filter effect causing of the upper and lower metallic conductor of prior art median filter.
The present invention, for solving the problems of the technologies described above, adopts following technical scheme:
Two ground plane electromagnetic interface filters, comprise tank type magnetic core, dull and stereotyped magnetic core and be arranged at tank type magnetic core and dull and stereotyped magnetic core between inductance unit, capacitor cell, between described inductance unit and capacitor cell, isolated substrate is set, described capacitor cell is included in a plurality of ceramic substrates that connect successively that arrange between two copper layers, between two ceramic substrates, by silver layer, connect, the outer surface that is positioned at outermost ceramic substrate is all connected with copper layer, described two equal ground connection of copper layer; Described inductance unit comprises pcb board and is arranged at the inductance coil circuit on pcb board; One end of described inductance coil circuit is the input of described planar EMI filter, and the other end is connected with the silver layer between ceramic substrate, and the output of planar EMI filter is set on described silver layer.
Described capacitor cell comprises the first bronze medal layer, the first ceramic substrate, the first silver layer, the second ceramic substrate, the second silver layer, the 3rd ceramic substrate, the second bronze medal layer connecting successively, wherein, and the first bronze medal layer, the equal ground connection of the second bronze medal layer; Described inductance unit comprises pcb board and is arranged at the first inductance coil circuit on pcb board two sides, the second inductance coil circuit, and wherein, the first inductance coil circuit, the second inductance coil circuit include first end, the second end; The first end of described the first inductance coil circuit is the first input end of described planar EMI filter, and the second end of described the first inductance coil circuit is connected with the first silver layer; The first end of described the second inductance coil circuit is the second input of described planar EMI filter, and the second end of described the second inductance coil circuit is connected with the second silver layer; The first output of planar EMI filter is set on described the first silver layer, the second output of planar EMI filter is set on described the second silver layer.
Described copper layer, silver layer are arranged on ceramic substrate by the mode that sprays or electroplate.
Described isolated substrate is PCB substrate.
Compared with prior art, the present invention has following beneficial effect:
1, because electric capacity adopts, in high-dielectric-constant ceramics base board both sides, be covered with silver layer or copper layer completely, well improved the symmetry of upper and lower metallic conductor.
2, simultaneously, according to plane-parallel capacitor formula, known, more electric capacity is larger for the corresponding area of upper and lower planar metal conductor, so this structure can effectively increase capacitance, makes it meet the designing requirement of planar EMI filter.
3, the present invention can be applicable in the making of electromagnetic interface filter, the lc unit integrated with common mode inductance, differential mode inductance and common mode capacitance in the past compared, because common mode capacitance and differential mode capacitor form an integral body by spraying plating technology, avoided via hole connection, be convenient to design and fabrication; Realized again " seamless " and connected, effectively reduced parasitic parameter simultaneously.
4, planar EMI filter structure of the present invention is not only convenient to make, and can obviously improve performance of filter.
Accompanying drawing explanation
Figure 1A is the planar annular electromagnetic interface filter structure of prior art.
Figure 1B is the common-mode filter structure of prior art.
Fig. 1 C is the equivalent lumped-parameter circuit of the common-mode filter of prior art.
Fig. 2 A is planar EMI filter integrated morphology of the present invention.
Fig. 2 B is the sectional view of planar EMI filter of the present invention.
Fig. 2 C is the lumped-parameter circuit of planar EMI filter of the present invention.
Fig. 3 A is the electric current signal of planar EMI filter of the present invention under common mode current.
Fig. 3 B is the electric current signal of planar EMI filter of the present invention under differential-mode current.
Wherein, being denoted as in figure: 301-tank type magnetic core; 302-the first bronze medal layer; 303-the first ceramic substrate; 304-the first silver layer; 305-the second ceramic substrate; 306-the second silver layer; 307-the 3rd ceramic substrate; 308-the second bronze medal layer; 309-insulating barrier; 310-the first inductance coil; 311-LC unit; 312-the second inductance coil; The dull and stereotyped magnetic core of 313-.
Embodiment
Below in conjunction with accompanying drawing, technical scheme of the present invention is elaborated:
Example as shown in Figure 2 A, the novel integrated morphology of a kind of pair of ground plane electromagnetic interface filter provided by the invention, comprise a tank type magnetic core 301 and a dull and stereotyped magnetic core 313, the integrated lc unit 311 of a slice, two inductance coils 312 and 310, two grounding copper layers 308 and 302, two silver layers 304 and 306, and three high-dielectric-constant ceramics plates 303,305 and 307.Copper layer and silver layer are plated on respectively high-dielectric-constant ceramics substrate both sides, form a gapless integral unit, and copper layer ground connection.One end A of the upper and lower helix of plane lc unit
2, B
2for input, the other end connects bottom many ground planes capacitance structure, as shown in Figure 2 B.If increase inductance value, can realize by increasing inductance coil.One end of inductance coil I and II is connected respectively upper and lower helix one end of integrated planar lc unit, and the other end of inductance coil I and II is input.One end of silver layer I and silver layer II connects the integrated lc unit of portion, other end C
2, D
2for output, its equivalent electric circuit as shown in Figure 2 C.Ring-shaped P CB plate is mainly used in solving the Insulation Problems of plane lc unit and many ground planes capacitance structure.
When passing into electric current, " silver layer-ceramic substrate-copper layer " structure can be considered common mode capacitance unit, and " silver layer-ceramic substrate-silver layer " structure can be considered differential mode capacitor unit.Meanwhile, owing to adopting spraying plating form, reduced the line between unit sheet, be not only convenient to make, and reduced due to the caused parasitic parameter problem of external connection line.Fig. 3 A and Fig. 3 B are respectively this novel integrated EMI filter in the current diagram passing in common mode current and differential-mode current situation.
When passing into common mode current, because the upper and lower coil winding-direction of lc unit is the same, and pile completely, therefore the voltage drop Δ U of each unit of upper and lower coil
iidentical, the both end voltage on its distributed capacitance is zero, does not embody the effect discharging and recharging.Therefore when passing into common mode current, can ignore the capacity effect of lc unit, just be equivalent to two planar coils of coupling mutually.For bottom many ground planes capacitance structure, because the current potential of silver layer is identical, therefore only there is common mode capacitance unit (Fig. 3 A).
When it passes into differential-mode current, its internal current distributes as shown in Figure 3 B, known according to transmission line theory, if the upper and lower coil full symmetric of plane lc unit only exists differential mode capacitor.And generally, due to the asymmetric leakage inductance that often exists of upper and lower coil, i.e. differential mode inductance.For bottom many ground planes capacitance structure, not only exist the differential mode capacitor between silver layer and silver layer, also because silver layer exists certain common mode capacitance with the non-complete equipotential in ground.
In the design process of electromagnetic interface filter, the number of turn of integrated LC structure coil is N
1, conductor width is t
1, ceramic wafer thickness is d
1.In many ground planes capacitance structure, ceramic substrate thickness is d
1, silver thickness is d
2, grounding copper layer thickness is d
3, loop configuration outer radius l
1, inside radius l
2, the magnetic circuit area of tank type magnetic core is A
e, the length of magnetic path is l
e, magnetic permeability is μ
r.
Electric capacity between the upper and lower coil of integrated planar lc unit is differential mode capacitor C
x2, as shown in Figure 2 C, its value is:
L is the total length of integrated lc unit single-layer spiral coil.
In many ground planes capacitance structure between " silver layer-ceramic substrate-silver layer " electric capacity as differential mode capacitor C
x1:
Common mode capacitance mainly in many ground planes capacitance structure between " silver layer-ceramic substrate-copper layer " electric capacity form, its value with differential mode capacitor C
x1identical.
Common mode inductance is produced by the upper and lower helical coil of integrated planar lc unit, and its value is:
Describe example of the present invention above in detail, but should be appreciated that embodiments of the present invention are not limited in this, this example is only for helping to understand the present invention.Various variation instance made for the present invention, all should be within the scope of the present invention.Scope of patent protection of the present invention should have appending claims to limit.
Of the present invention pair of ground plane also can expand to many ground planes as required, and the many ground planes in specification comprise the structure of two ground planes.
Claims (4)
1. pair ground plane electromagnetic interface filter, comprise tank type magnetic core, dull and stereotyped magnetic core and be arranged at tank type magnetic core and dull and stereotyped magnetic core between inductance unit, capacitor cell, it is characterized in that, between described inductance unit and capacitor cell, isolated substrate is set, described capacitor cell is included in a plurality of ceramic substrates that connect successively that arrange between two copper layers, between two ceramic substrates, by silver layer, connect, the outer surface that is positioned at outermost ceramic substrate is all connected with copper layer, described two equal ground connection of copper layer; Described inductance unit comprises pcb board and is arranged at the inductance coil circuit on pcb board; One end of described inductance coil circuit is the input of described planar EMI filter, and the other end is connected with the silver layer between ceramic substrate, and the output of planar EMI filter is set on described silver layer.
2. according to claim 1 pair of ground plane electromagnetic interface filter, it is characterized in that: described capacitor cell comprises the first bronze medal layer, the first ceramic substrate, the first silver layer, the second ceramic substrate, the second silver layer, the 3rd ceramic substrate, the second bronze medal layer connecting successively, wherein, the first bronze medal layer, the equal ground connection of the second bronze medal layer; Described inductance unit comprises pcb board and is arranged at the first inductance coil circuit on pcb board two sides, the second inductance coil circuit, and wherein, the first inductance coil circuit, the second inductance coil circuit include first end, the second end; The first end of described the first inductance coil circuit is the first input end of described planar EMI filter, and the second end of described the first inductance coil circuit is connected with the first silver layer; The first end of described the second inductance coil circuit is the second input of described planar EMI filter, and the second end of described the second inductance coil circuit is connected with the second silver layer; The first output of planar EMI filter is set on described the first silver layer, the second output of planar EMI filter is set on described the second silver layer.
3. according to claim 1 and 2 pair of ground plane electromagnetic interface filter, is characterized in that: described copper layer, silver layer are arranged on ceramic substrate by the mode that sprays or electroplate.
4. according to claim 1 and 2 pair of ground plane electromagnetic interface filter, is characterized in that: described isolated substrate is PCB substrate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410193132.0A CN103986437B (en) | 2014-05-08 | 2014-05-08 | Double ground plane electromagnetic interface filters |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410193132.0A CN103986437B (en) | 2014-05-08 | 2014-05-08 | Double ground plane electromagnetic interface filters |
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| Publication Number | Publication Date |
|---|---|
| CN103986437A true CN103986437A (en) | 2014-08-13 |
| CN103986437B CN103986437B (en) | 2017-06-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410193132.0A Expired - Fee Related CN103986437B (en) | 2014-05-08 | 2014-05-08 | Double ground plane electromagnetic interface filters |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108880207A (en) * | 2018-07-27 | 2018-11-23 | 西安电子科技大学 | High-power 3D integrated form three-phase electromagnetic interface filter |
| CN110098817A (en) * | 2018-01-29 | 2019-08-06 | 意法半导体(图尔)公司 | Common-mode filter |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100264145B1 (en) * | 1997-06-20 | 2000-08-16 | 이종수 | Inductor for containing common mode filter and differential mode filter |
| CN101854152A (en) * | 2010-04-30 | 2010-10-06 | 南京航空航天大学 | Planar electromagnetic interference (EMI) filter integration module consisting of circular printed circuit board (PCB) wire turns |
| CN102647166A (en) * | 2012-04-18 | 2012-08-22 | 南京航空航天大学 | Inductance-capacitance module for forming plane EMI (Electric-Magnetic Interference) filter |
| CN103780216A (en) * | 2014-01-24 | 2014-05-07 | 南京航空航天大学 | Whole-plane EMI filter integrated structure composed of round-plane PCB coupling inductors |
-
2014
- 2014-05-08 CN CN201410193132.0A patent/CN103986437B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100264145B1 (en) * | 1997-06-20 | 2000-08-16 | 이종수 | Inductor for containing common mode filter and differential mode filter |
| CN101854152A (en) * | 2010-04-30 | 2010-10-06 | 南京航空航天大学 | Planar electromagnetic interference (EMI) filter integration module consisting of circular printed circuit board (PCB) wire turns |
| CN102647166A (en) * | 2012-04-18 | 2012-08-22 | 南京航空航天大学 | Inductance-capacitance module for forming plane EMI (Electric-Magnetic Interference) filter |
| CN103780216A (en) * | 2014-01-24 | 2014-05-07 | 南京航空航天大学 | Whole-plane EMI filter integrated structure composed of round-plane PCB coupling inductors |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110098817A (en) * | 2018-01-29 | 2019-08-06 | 意法半导体(图尔)公司 | Common-mode filter |
| CN110098817B (en) * | 2018-01-29 | 2024-05-28 | 意法半导体(图尔)公司 | Common mode filter |
| CN108880207A (en) * | 2018-07-27 | 2018-11-23 | 西安电子科技大学 | High-power 3D integrated form three-phase electromagnetic interface filter |
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| Publication number | Publication date |
|---|---|
| CN103986437B (en) | 2017-06-13 |
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Granted publication date: 20170613 Termination date: 20190508 |