WO2011013543A1 - コモンモードフィルタ - Google Patents
コモンモードフィルタ Download PDFInfo
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- WO2011013543A1 WO2011013543A1 PCT/JP2010/062208 JP2010062208W WO2011013543A1 WO 2011013543 A1 WO2011013543 A1 WO 2011013543A1 JP 2010062208 W JP2010062208 W JP 2010062208W WO 2011013543 A1 WO2011013543 A1 WO 2011013543A1
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- 230000005540 biological transmission Effects 0.000 claims abstract description 34
- 239000004020 conductor Substances 0.000 claims abstract description 15
- 239000000758 substrate Substances 0.000 claims description 29
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- 238000010586 diagram Methods 0.000 description 8
- 230000002238 attenuated effect Effects 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 239000003990 capacitor Substances 0.000 description 4
- 238000010521 absorption reaction Methods 0.000 description 3
- 230000005672 electromagnetic field Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000004907 flux Effects 0.000 description 2
- 230000010363 phase shift Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000005670 electromagnetic radiation Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/20—Frequency-selective devices, e.g. filters
- H01P1/201—Filters for transverse electromagnetic waves
- H01P1/203—Strip line filters
- H01P1/20327—Electromagnetic interstage coupling
- H01P1/20336—Comb or interdigital filters
- H01P1/20345—Multilayer filters
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/20—Frequency-selective devices, e.g. filters
- H01P1/201—Filters for transverse electromagnetic waves
- H01P1/203—Strip line filters
- H01P1/2039—Galvanic coupling between Input/Output
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/42—Networks for transforming balanced signals into unbalanced signals and vice versa, e.g. baluns
- H03H7/425—Balance-balance networks
- H03H7/427—Common-mode filters
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F17/00—Fixed inductances of the signal type
- H01F17/0006—Printed inductances
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H1/00—Constructional details of impedance networks whose electrical mode of operation is not specified or applicable to more than one type of network
- H03H2001/0021—Constructional details
- H03H2001/0085—Multilayer, e.g. LTCC, HTCC, green sheets
Definitions
- the present invention relates to a common mode filter, and more particularly to a novel common mode filter that secures the passage of an ultra-high speed differential signal propagating through an ultra-high speed differential transmission line and attenuates the common mode signal.
- This differential transmission system ensures both high transmission speed and small amplitude for power saving by simultaneously sending positive and negative differential signals to each of the paired two lines. Common mode signals such as noise are attenuated.
- the differential transmission system has an insufficient function of attenuating common mode signals such as external noise, and a common mode choke coil is inserted in the differential transmission line in order to avoid the adverse effects.
- FIG. 16 shows a circuit diagram thereof.
- the differential signals flowing through the two conductors cancel each other out of phase with each other, so that no magnetic flux is generated and the impedance of the two conductors is kept low. Easy to pass.
- the common mode signal flows through the two conductors in the same phase to generate a magnetic flux in the magnetic material, the impedance of the two conductors becomes high and the signal hardly passes, and the common mode signal is attenuated.
- Patent Document 1 The common mode choke coil for differential transmission lines disclosed in Japanese Patent Laid-Open No. 2000-58343 (Patent Document 1) corresponds to the configuration shown in FIG.
- Patent Document 1 two coil conductors wound around a toroidal core are accommodated in a resin-made outer case made up of a case portion and a lid portion, and the outer surface and bottom of the outer peripheral wall of the case portion.
- a ground conductor is plated on the outer surface of the wall and the outer surface of the lid, an insulating film is formed on the ground conductor, a terminal plate is bonded to each of the insulating films, and an end portion of the coil conductor is attached to the terminal plate.
- the pass characteristic Scc21 of the common mode signal is V-shaped, and attenuation of about ⁇ 20 dB is obtained in the range of 2 to 3 GHz, but the attenuation amount is small in the range of 8 to 10 GHz. It is difficult to attenuate common mode signals sufficiently.
- the transmission characteristic Scc21 of the common mode signal is close to the limit, and it is difficult to cope with good transmission of ultrahigh-speed differential signals that will be required in the future.
- common mode signals that do not pass are reflected at the input end of the common mode choke coil, propagated in the reverse direction of the line, and may be electromagnetically emitted to the outside when reflected, which is likely to cause noise. .
- the signal in the GHz band has a short wavelength, the probability that the wavelength matches an integer multiple of the circuit pattern length increases, and the possibility that the circuit pattern becomes an antenna and is radiated electromagnetically increases.
- the present invention has been made to solve such a problem.
- a desirable ultrahigh-speed differential signal can be satisfactorily passed, and an undesirable common mode signal can be blocked only by reflection.
- An object is to provide a common mode filter that can be absorbed and attenuated internally.
- a common mode filter according to claim 1 of the present invention is separated from a pair of conductive lines formed in the first dielectric layer for transmitting a differential signal and an external ground potential,
- the first dielectric layer faces the conductive line with the first dielectric layer interposed therebetween, and is divided into a plurality of parts along the length of the conductive line.
- a plurality of first divided floating grounds forming a differential transmission line, and between the first divided floating grounds located at least on the input side or the output side among the first divided floating grounds and the external ground potential And a first passive two-terminal circuit connected to.
- the common mode filter according to claim 2 of the present invention has a configuration in which the first divided floating ground is a pair of the input side and the output side.
- the common mode filter according to claim 3 of the present invention has a configuration in which three or more first divided floating grounds are formed.
- the common mode filter according to claim 4 of the present invention has a configuration in which the first divided floating ground is connected to the first passive two-terminal circuit between all or some of the adjacent divided floating grounds. is doing.
- the common mode filter according to claim 5 of the present invention has a configuration in which a first passive two-terminal circuit having a plurality of adjacent first divided floating grounds is connected.
- the common mode filter according to claim 6 of the present invention has a configuration in which the conductive line is a rectangular conductive line.
- a common mode filter according to a seventh aspect of the present invention has a configuration in which a plurality of spiral conductive lines are connected in series in the length direction.
- the conductive line is formed on a dielectric substrate as the first dielectric layer, and the first divided floating ground is different from the dielectric substrate.
- the different dielectric substrates are laminated and integrated.
- a common mode filter according to claim 9 of the present invention is separated from the external ground potential, and is formed to face the conductive line with the second dielectric layer interposed therebetween, and its distributed constant type differential transmission The second floating ground that forms the line is provided.
- the common mode filter according to claim 10 of the present invention has a second passive two-terminal circuit connected between the second floating ground and the external ground potential.
- the second floating ground is divided into a plurality in the length direction of the conducting line, and at least a second divided floating ground on the input side or the output side among them.
- the second passive two-terminal circuit is connected to the external ground potential.
- a common mode filter according to a twelfth aspect of the present invention has a configuration in which the second passive floating terminal is connected between all or some of the adjacent divided floating grounds. is doing.
- the conductive line is formed on a dielectric substrate as the first dielectric layer, and the first divided floating ground is different from the dielectric substrate.
- the second floating ground is formed on the dielectric substrate as the second dielectric layer, and different dielectric substrates are laminated and integrated.
- a common mode filter according to a fourteenth aspect of the present invention has a configuration in which the first and second passive two-terminal circuits are short-circuit lines.
- a common mode filter according to a fifteenth aspect of the present invention has a configuration in which the first and second passive two-terminal circuits are inductance, capacitance, resistance, or a combination thereof as one or more passive elements. Yes.
- a pair of conductive lines for transmitting a differential signal is formed in the first dielectric layer, and the first dielectric layer is interposed.
- the first divided floating ground is formed in a state of facing the conductive line and being divided into a plurality of parts in the length direction, and at least the first divided floating ground on the input side or the output side and the external ground potential Since the first passive two-terminal circuit is connected between them, a distributed constant differential transmission line for the differential signal is formed by the conductive line and the first divided floating ground, and the conductive line and the first A series resonant circuit for a common mode signal is formed with a passive two-terminal circuit, and in an ultra-high-speed differential transmission line, an undesirable common-mode signal is cut off and attenuated by internal absorption, while a desirable ultra-high-speed difference It is possible to satisfactorily pass signals.
- the first divided floating ground is connected to the first passive two-terminal circuit between all or some of the divided floating grounds adjacent to each other.
- Various attenuation characteristics for the common mode signal can be obtained.
- the conductive line is formed of a rectangular conductive line, in addition to the above-described effects, desired delay characteristics of the ultrahigh-speed differential signal are arbitrarily set. It is possible.
- the conductive line is formed by connecting a plurality of spiral conductive lines in series in the length direction, in addition to the above-described effects, a desirable ultra-high speed differential signal delay It is possible to increase the characteristics.
- the conductive line is formed on a dielectric substrate as the first dielectric layer, and the first divided floating ground is different from the dielectric substrate.
- these different dielectric substrates are laminated and integrated, a chip-type configuration can be easily obtained.
- the distributed constant type differential transmission is formed so as to be separated from the external ground potential and to face the conductive line with the second dielectric layer interposed therebetween. Since the second floating ground forming the line is provided, the above-described effects can be obtained in the stripline configuration.
- the second floating ground is divided into a plurality of divided floating grounds, and at least between the second divided floating ground on the input side or the output side and the external ground potential. Since the two passive two-terminal circuits are connected, the stripline configuration can provide a better effect and maintain the simplification of the configuration.
- the first and second passive two-terminal circuits are formed of a short circuit line, an inductance, a capacitance, a resistance as one or more passive elements, or a combination thereof. Therefore, various effects described above can be obtained with a simple element configuration.
- FIG. 8 is a pass characteristic diagram of the common mode filter of FIG. 7.
- FIG. 8 is a power distribution characteristic diagram of the common mode filter of FIG. 7. It is a disassembled perspective view which shows another embodiment of the common mode filter of this invention.
- FIG. 14 is a power distribution characteristic diagram of the common mode filter of FIG. 13.
- FIG. 17 is a characteristic diagram of the conventional common mode filter shown in FIG. 16.
- FIG. 1 is an exploded perspective view showing a basic configuration of a common mode filter F according to the present invention.
- FIG. 1 On one side (upper surface in FIG. 1) of a rectangular dielectric layer 3A made of a dielectric substrate such as sintered ceramics, a pair of conductive lines folded in a rectangular shape between opposing edges of the dielectric layer 3A 1A and 1B are formed by a conventionally known printing method or the like.
- the conducting lines 1A and 1B are connected to input terminals 5A and 5B and output terminals 7A and 7B formed at other opposing edges of the dielectric layer 3A.
- the input terminals 5A and 5B and the output terminals 7A and 7B are shown in different locations from the dielectric layer 3A for convenience.
- the conducting lines 1A, 1B and the input / output terminals 5A, 5B, 7A, 7B are formed and arranged symmetrically with respect to a virtual line (not shown) passing between the conducting lines 1A, 1B.
- a dielectric layer 3B made of a dielectric substrate having the same shape and the same material as the dielectric layer 3A is disposed below the dielectric layer 3A.
- Divided floating grounds 9A and 9B are formed over almost the entire area of one surface (upper surface in FIG. 1) of the dielectric layer 3B by a known printing technique or the like.
- the divided floating grounds 9A and 9B are formed independently and in parallel with each other at a slight interval in a region that bisects the direction between the input terminals 5A and 5B and the output terminals 7A and 7B in the dielectric layer 3B. It faces the conducting lines 1A and 1B via the dielectric layer 3A.
- CM1A and CM1B are connected.
- the end close to the output terminals 7A and 7B is a connection point 11B, and the passive two-terminal circuits CM1C and CM1D are connected between these and the output-side ground terminals 15A and 15B.
- the passive two-terminal circuits CM1A to CM1D are connection pieces as short-circuit lines, inductors by folded lines, capacitances by plate electrodes, or resistance films, and are formed on the dielectric layer 3B.
- a dielectric layer 3C made of a dielectric substrate having the same shape and the same material as the dielectric layer 3A is disposed above the dielectric layer 3A.
- Input-side ground terminals 13A and 13B and output-side ground terminals 15A and 15B are formed on the opposite edge of the dielectric layer 3C similar to the dielectric layer 3A.
- the different dielectric layers 3A, 3B, and 3C are overlapped and integrated in a chip shape to form a microstrip distributed constant type common mode filter F.
- the input / output terminals 5A to 7B, the input-side ground terminals 13A and 13B, and the output-side ground terminals 15A and 15B formed on the dielectric layers 3A to 3C are integrated in a chip shape by overlapping the dielectric layers 3A to 3C. Are integrated in the same way.
- FIG. 2 shows that the delay time of the differential transmission line of the microstrip distributed constant type is 100 ps in the configuration of FIG. 1, and the passive two-terminal circuits CM1A to CM1D are the same as the 0.3 mm-wide connection piece (short-circuit line). This is a result of electromagnetic field analysis by dividing the floating grounds 9A and 9B at the central portion by using a 50 ⁇ resistive film.
- curves Scc21 (1) and Scc21 (2) are common mode signal passing characteristics under the following conditions.
- Sdd21 is a passive two-terminal circuit This is a differential signal passing characteristic when CM1A to CM1D are resistance films having a width of 0.3 mm and 50 ⁇ .
- the attenuation frequency band of the common mode signal is about 4 to 11 GHz, and in particular 5 to 10.5 GHz, the attenuation is 15 dB or more.
- the passive two-terminal circuits CM1A to CM1D are resistors of 50 ⁇ , as shown in Scc21 (2), the attenuation of the common mode signal is smaller than that of Scc21 (1), but a certain amount of attenuation is obtained in a wider band. In particular, an attenuation of 5 to 15 dB is obtained in a frequency range of 3 to 17 GHz.
- the configuration in which the floating ground is not divided is a characteristic that the common mode signal passes in a band of direct current (DC) to 10 GHz or more and is difficult to be practically used as the common mode filter F.
- DC direct current
- FIG. 3 is an equivalent circuit in the configuration of FIG. Between the divided floating grounds 9A and 9B, there is a capacitance 17 between the divided floating grounds.
- the constant value by electromagnetic field analysis and the characteristics shown in FIG. 2 can be obtained from the capacitance value of the divided floating ground capacitance 17 and the inductance value when the passive two-terminal circuits CM1A to CM1D are short-circuited lines having a width of 0.3 mm.
- the divided floating ground capacitance 17 was 0.5 pF
- the inductances of the passive two-terminal circuits CM1A to CM1D were 0.6 nH.
- FIG. 4 shows a circuit simulation result of the equivalent circuit shown in FIG.
- Scc21 (1) and Scc21 (2) are common mode signal passing characteristics under the following conditions.
- Sdd21 is a differential signal passing characteristic when the passive two-terminal circuits CM1A to CM1D are a series circuit of a 50 ⁇ resistor and a 0.6 nH inductor.
- the capacity 17 between the divided floating grounds can be adjusted by the gap size between the divided floating grounds. In other words, it is equivalent to connecting a capacitor as a passive two-terminal circuit between the divided floating grounds. Although not shown, it is also possible to adjust the common mode pass characteristic by connecting another passive two-terminal circuit between the divided floating grounds.
- the common mode signals applied to the conductive lines 1A and 1B are in phase, they are transferred from the divided floating grounds 9A and 9B to the external ground potential via the divided floating ground capacitance 17 and the passive two-terminal circuits CM1A to CM1D. Flowing. That is, the divided floating ground capacitor 17 and the passive two-terminal circuits CM1A to CM1D are effective elements only for the common mode signal.
- the passive two-terminal circuits CM1A to CM1D are short-circuited lines, they have an inductor component, so that a series resonant circuit for the common mode signal is formed together with the divided floating ground capacitance 17.
- the split floating grounds 9A and 9B do not function as grounds for the common mode signal
- the conductive lines 1A and 1B are not transmission lines for the common mode signal, and the inductors and capacitors forming the conductive lines 1A and 1B have the above-described characteristics. They are connected in series to a series resonant circuit, which form a complex resonant circuit.
- a resonance curve as shown by Scc21 (1) in FIG. 4 is obtained, and functions as a filter for the common mode signal.
- the delay time increases, the time constants such as inductance and capacitance of the conductive lines 1A and 1B increase, and the resonance frequency also decreases. That is, as the delay time increases, the common mode signal can be attenuated from a lower frequency.
- the outer shape is the same as that of the short-circuit line, and therefore has an inductance component, and can be regarded as a series element of resistance and inductance in terms of an equivalent circuit. .
- the passing characteristic has a broad resonance curve as shown by Scc21 (2) in FIG. 4 by decreasing the “Q” of the resonance circuit when a resistance enters the resonance circuit. That is, the attenuation amount of the common mode signal is reduced, but a certain amount of attenuation is obtained in a wide band. Further, since the resistor is connected to the resonance circuit, a part of the input common mode signal power is lost by the resistor.
- FIG. 5 shows that when the passive two-terminal circuits CM1A to CM1D in FIG. 1 are short-circuited lines, the common mode signal power input to the common mode filter F is assumed to be 100%, and the frequency passes at every frequency. This shows the ratio of reflection.
- the remaining power obtained by subtracting the passing power and the reflected power from the total power is the common mode signal power absorbed and consumed in the common mode filter F, and this is defined as the absorbed power.
- the common mode signal power input to the common mode filter F is assumed to be 100%, and the passing power for each frequency.
- the ratio, the ratio of reflected power, and the ratio of absorbed power are shown.
- the reflected power occupies a high ratio at 4 to 11 GHz so as to correspond to the characteristics of the attenuation band 4 to 11 GHz of Scc (1) in FIG. 2, and much of the common mode signal power that does not pass through the common mode filter F. Is reflected at the input terminal. Although some absorbed power is generated, this may be due to dielectric loss or conductor loss of members constituting the common mode filter F.
- the absorbed power occupies a high ratio at 3 to 17 GHz corresponding to the characteristics of the attenuation band 3 to 17 GHz of Scc (2) in FIG. Yes. That is, it is shown that much of the common mode signal power that does not pass through the common mode filter F is absorbed internally and the reflected power is suppressed.
- FIG. 7 is an exploded perspective view showing another embodiment according to the common mode filter F of the present invention, in which a passive two-terminal circuit is connected in series with a plurality of types of passive two-terminal elements, and a plurality of divided floating grounds are In this configuration, one passive two-terminal circuit is connected in common.
- the divided floating grounds in FIG. 1 are further divided to form divided floating grounds 9A to 9D, while passive two-terminal circuits CM1A and CM1B connected to the input side ground terminals 13A and 13B and the output side Passive two-terminal circuits CM1C and CM1D connected to the ground terminals 15A and 15B are formed of a series circuit of a rectangular inductance and a resistor having a value larger than that of the short-circuit line.
- the split floating ground 9A is connected to the input-side ground terminals 13A and 13B via passive two-terminal circuits CM1A and CM1B each formed of a series circuit of a resistor and an inductor that form a passive two-terminal circuit.
- the divided floating grounds 9B to 9D are connected to the output-side ground terminals 15A and 15B via passive two-terminal circuits CM1C and CM1D each composed of a series circuit of a resistor and an inductor, which are passive two-terminal elements.
- the passive two-terminal circuits CM1C and CM1D are shared and connected in parallel to the divided floating grounds 9B to 9D, and the inductance is set to a value larger than that of the passive two-terminal circuits CM1A and CM1B.
- the divided floating grounds 9A to 9D are divided more and the inductance values of the passive two-terminal circuits CM1A to CM1D connected to each of the divided floating grounds 9A to 9D become a plurality of resonance frequencies. Are divided into a plurality, and a wide common mode signal attenuation band is obtained.
- FIG. 9 shows the ratio of the passing power, reflected power and absorbed power to the input common mode signal power in the common mode filter F having the passing characteristic Scc21 of FIG. It is shown that mode power absorption occurs.
- the common mode filter F according to the present invention is a microstrip distributed constant type differential transmission line as a distributed constant type differential transmission line has been described.
- the common mode filter F of the present invention uses a distributed constant type differential transmission line in which a pair of conductive lines face the ground from above and below via a dielectric, that is, a strip distributed constant type differential conductive line. Is also possible.
- FIG. 10 is an exploded perspective view showing a common mode filter F of the present invention using a strip distributed constant type differential conducting line.
- a dielectric layer 3B similar to that in the same figure is disposed below the dielectric layer 3A as in FIG.
- a passive two-terminal circuit CM1E made of resistance (for example, 50 ⁇ ) formed by printing or the like is connected between the adjacent divided floating grounds 9E to 9H. .
- Both ends of the split floating ground 9E on the input side are connected to the input ground terminals 13A and 13B via a passive two-terminal circuit CM1E made of a resistor, and both ends of the split floating ground 9H on the output side are connected to the output side. It is connected to ground terminals 15A and 15B.
- a dielectric layer 3D made of a dielectric substrate having the same shape and the same material as the dielectric layer 3A is disposed between the dielectric layer 3C and the same.
- elongated divided floating grounds 19E, 19F, 19G, and 19H extending so as to cross, for example, orthogonal to the input / output directions of the conductive lines 1A and 1B are slightly spaced. Are formed in parallel so as to be close to each other.
- the individual divided floating grounds 19E to 19H have the same shape as the divided floating grounds 9E to 9H, and are formed at positions overlapping with these.
- a passive two-terminal circuit CM2E made of resistance (for example, 50 ⁇ ) formed by printing or the like is connected between the adjacent divided floating grounds 19E to 19H. .
- the divided floating ground 19E on the input side is connected to the input side ground terminals 13A and 13B via a passive two-terminal circuit CM2E made of a resistor, and both ends of the divided floating ground 19H on the output side are connected to the output side ground terminal 15A. , 15B.
- the different dielectric layers 3A, 3B, 3D, and 3C are stacked and integrated in a chip shape.
- the input / output terminals 5A, 5B, 7A, and 7B and the input / output side ground terminals 13A, 13B, 15A, and 15B formed on the dielectric layers 3A, 3B, 3C, and 3D are stacked with the dielectric layers 3A to 3D on top of each other. Are integrated in the same way.
- the dielectric layer 3A, the divided floating grounds 9E to 9H, and the passive two-terminal circuit CM1E are respectively the first dielectric layer, the first divided floating ground, and the first passive two-terminal circuit.
- the dielectric layer 3D, the divided floating grounds 19E to 19H, and the passive two-terminal circuit CM2E are respectively a second dielectric layer, a second divided floating ground (second floating ground), and a second passive layer. Functions as a two-terminal circuit.
- the divided floating grounds 9E, 9H, 19E, and 19H on the input side and the output side are connected to the external ground via the passive two-terminal circuits CM1E and CM2E, and the adjacent divided floating grounds 9E to 9E are connected.
- Passive two-terminal circuits CM1E and CM2E are connected between 9H and 19E to 19H.
- FIG. 11 shows the characteristics of the common mode filter F shown in FIG. 10 in which the differential conducting line has a delay time of 100 ps.
- Sdd21 shows the differential signal passing characteristics and Scc21 shows the common mode signal passing characteristics. It can be seen that both characteristics have sufficient characteristics as the common mode filter F.
- the common mode filter F most of the input common mode power is absorbed by the passive two-terminal circuits CM1E and CM2E, and the resonance of the circuit is used to obtain the common mode signal attenuation characteristics, and Energy is absorbed in a total of 20 resistors having a resistance value of 50 ⁇ , which are the passive two-terminal circuits CM1E and CM2E, and a great effect is obtained. Therefore, good distribution characteristics can be obtained as shown in FIG.
- CM1E and CM2E are arranged in total, and these are formed by a printing method using a resistor paste, and the shapes of the dielectric layers 3B and 3D are the same. So production is also very good.
- the second floating ground functions only as an impedance matching ground for differential signals, and the function of the common mode filter F is maintained by the first divided floating grounds 9E to 9H.
- the passive two-terminal circuit CM1E is not connected to any of the divided floating grounds 9E to 9H, and the passive two-terminal circuit CM2E is connected to any of the divided floating grounds 19E to 19H. Even if the first divided floating ground and the second floating ground are both incompletely configured, the function as the common mode filter F is maintained although the characteristics are deteriorated. It is not always necessary to connect the passive two-terminal circuit to all the divided floating grounds.
- the conductive lines 1A and 1B have been described by using microstrip lines or strip lines by rectangular folded lines.
- the common mode filter F of the present invention can use a spiral-shaped distributed constant line for the conductive line.
- FIG. 13 is an exploded perspective view showing a common mode filter F of the present invention using a spiral distributed constant type differential conducting line.
- FIG. 13 is the stripline configuration shown in FIG. 10 and is formed of a dielectric substrate by forming a dielectric layer similar to the dielectric layer 3A between the dielectric layer 3A and the dielectric layer 3D. A dielectric layer 3E is inserted.
- spiral conductive lines 21A and 21B are formed on the dielectric layer 3A, and spiral conductive lines 23A and 23B are formed on the dielectric layer 3E by a technique such as printing.
- the spiral conductive lines 21A, 21B, 23A and 23B are formed by arranging a plurality of unit spiral coils in a direction across the divided floating grounds 9E to 9H and 19E to 19H at a slight interval. And a pair of unit spiral coils connected in series next to each other.
- the unit spiral coils of the spiral conductive lines 21A and 23A are alternately connected in series between the input / output terminals 5A and 7A, and the unit spiral coils of the spiral conductive lines 21B and 23B are connected between the input / output terminals 5B and 7B. They are connected in series alternately.
- the coupling spiral coil on the side closest to the input terminals 5A and 5B has a size that fits within the width of the divided floating grounds 9E and 19E, and has a distributed capacity by being sandwiched between the divided floating grounds 9E and 19E from above and below.
- the inductance is lumped constant, but the capacitance is distributed constant, so a distributed constant line is formed.
- a similar coupled spiral coil is sandwiched between the split floating grounds 9F and 19F, between 9G and 19G, and between 9H and 19H.
- the divided floating grounds 9E and 19E, 9F and 19F, 9G and 19G, and 9H and 19H are connected to each other by vias 25C and 25D that pass through portions avoiding the conductive lines 21A, 21B, 23A, and 23B. .
- FIG. 14 shows the differential signal passing characteristic Sdd21 and the common mode signal passing characteristic Scc21 when the delay time is set to about 200 ps in the common mode filter F shown in FIG.
- the passive two-terminal circuit CM1E is 50 ⁇ and the CM2E is 100 ⁇ .
- the delay time increases, so the time constant of the complex series resonant circuit for the common mode signal also increases. Therefore, the frequency band for attenuating the common mode signal is shifted to the lower side, and from around 3 GHz. It is shown that it becomes a common mode filter that can be used in the frequency band.
- FIG. 15 shows the distribution characteristics of the common mode power input to the common mode filter F shown in FIG. From this figure, it can be seen that in the configuration of the present invention, although the reflected power slightly increases near 11 GHz, generally good power absorption is obtained.
- the input side ground terminals 13A and 13B are arranged side by side with the input terminals 5A and 5B, and the output side ground terminals 15A and 15B are also arranged side by side with the output terminals 7A and 7B. It was explained with an example.
- the input terminals 5A, 5B are arranged on one side of the square chip component, only the output terminals 7A, 7B are arranged on the opposite side, and the input / output terminals 5A, 5B, 7A, 7B are not arranged. It is necessary to collect the input / output side ground terminals 13A, 13B, 15A, and 15B together on the sides and the bottom and arrange them as common terminals. In this case, the input / output side ground terminals 13A, 13B, 15A, and 15B can be integrated.
- the configuration described above is the same as the configuration using the distributed constant differential transmission line by stripline or microstripline. Various combinations of these are possible.
- a plurality of passive two-terminal circuits CM1A to CM2E used for one common mode filter F are all assumed to be the same type of passive elements or a combination of resistors and inductances. .
- the passive two-terminal circuits CM1A to CM2E in one common mode filter F can be used in any combination of inductance, short-circuit line, capacitance, and resistance.
- common mode filter F of the present invention can be configured not only as a single component but also combined with other functional components.
- a passive two-terminal circuit may be connected to as many divided floating grounds as the number, and the remaining portion may be divided floating grounds that are not connected to the passive two-terminal circuit.
- microstrip lines strip lines, and spiral lines are illustrated as examples of distributed constant type differential conductive lines having a split floating ground where a pair of conductive lines face each other across a dielectric layer.
- the cross-sectional shapes of the pair of conductive lines it is not necessary for the cross-sectional shapes of the pair of conductive lines to be planar rectangles juxtaposed on the same plane, and the pair of conductive lines face each other with a dielectric interposed therebetween.
- the ground need not be flat.
- a twisted pair of insulation-coated conductors are covered with an insulator that functions as a dielectric, and the surroundings are covered with a round conductor, and a plurality of them are continuously arranged so as not to contact each other.
- the ground can function as a split floating ground, and the effect of the present invention can be realized.
- the pair of conductive lines has been analyzed as having the same delay time, but the conductive lines may have a delay time difference.
- the common mode filter F can simultaneously obtain the effects of correcting the phase shift and attenuating the common mode signal.
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- Electromagnetism (AREA)
- Filters And Equalizers (AREA)
- Coils Or Transformers For Communication (AREA)
Abstract
Description
Scc21(1):受動2端子回路CM1A~Dが幅0.3mmの短絡線路
Scc21(2):受動2端子回路CM1A~Dが幅0.3mmの50Ω抵抗膜
なお、Sdd21は、受動2端子回路CM1A~CM1Dを幅0.3mmで50Ωの抵抗膜とした場合の差動信号通過特性である。
Scc21(1):受動2端子回路CM1A~CM1Dは0.6nHのインダクタ(幅0.3mmの短絡線路に相当)
Scc21(1):受動2端子回路CM1A~CM1Dは50Ωの抵抗と0.6nHのインダクタの直列接続(幅0.3mmの50Ω抵抗膜に相当)
なお、Sdd21は、受動2端子回路CM1A~CM1Dを、50Ωの抵抗と0.6nHのインダクタとの直列回路とした場合での差動信号通過特性である。
3A、3B 誘電体層(第1の誘電体層)
3C 誘電体層(第2の誘電体層)
3D 誘電体層
3E 誘電体層(第1の誘電体層)
5A、5B 入力端子
7A、7B 出力端子
9A、9B、9C、9D、9E、9F、9G、9H 分割浮きグランド(第1の分割浮きグランド)
13A、13B 入力側グランド端子
15A、15B 出力側グランド端子
17 分割浮きグランド間容量
19E、19F、19G、19H 分割浮きグランド(第2の浮きグランド)
25A、25B、25C、25D ビア
21A、21B スパイラル状導線路
23A、23B スパイラル状導線路
CM1A、CM1B、CM1C,CM1D、CM1E 受動2端子回路(第1の受動2端子回路)
CM2E 受動2端子回路(第2の受動2端子回路)
F コモンモードフィルタ
Claims (15)
- 第1の誘電体層に形成され差動信号を伝送させる一対の導線路と、
外部グランド電位から分離され、前記第1の誘電体層を介在させた状態で前記導線路と対面するとともに、前記導線路の長さ方向に複数個に分割され形成され、前記導線路とともに前記差動信号に対して分布定数型の差動伝送線路を形成する複数の第1の分割浮きグランドと、
これら第1の分割浮きグランドのうち、少なくとも入力側又は出力側に位置する第1の分割浮きグランドと前記外部グランド電位との間に接続された第1の受動2端子回路と、
を具備することを特徴とするコモンモードフィルタ。 - 前記第1の分割浮きグランドは、前記入力側および出力側の1対である請求項1記載のコモンモードフィルタ。
- 前記第1の分割浮きグランドは、3個以上形成された請求項1記載のコモンモードフィルタ。
- 前記第1の分割浮きグランドは、隣り合う全て又は一部の前記分割浮きグランド間にも前記第1の受動2端子回路が接続された請求項2又は3記載のコモンモードフィルタ。
- 隣り合う複数の前記第1の分割浮きグランドは、共通の前記第1の受動2端子回路が接続された請求項3記載のコモンモードフィルタ。
- 前記導線路は矩形状の導線路である請求項1~5いずれか1記載のコモンモードフィルタ。
- 前記導線路はスパイラル状の導線路が前記長さ方向に複数直列接続されてなる請求項1~5いずれか1記載のコモンモードフィルタ。
- 前記導線路は、前記第1の誘電体層としての誘電体基板に形成され、前記第1の分割浮きグランドは前記誘電体基板と異なる誘電体基板に形成されるとともに、それら異なる前記誘電体基板が積層一体化されてなる請求項1~7いずれか1記載のコモンモードフィルタ。
- 前記外部グランド電位から分離され、第2の誘電体層を介在させた状態で前記導線路と対面するよう形成され、前記分布定数型の差動伝送線路を形成する第2の浮きグランドを有する請求項1~7いずれか1記載のコモンモードフィルタ。
- 前記第2の浮きグランドおよび前記外部グランド電位の間に接続される第2の受動2端子回路を有する請求項9記載のコモンモードフィルタ。
- 前記第2の浮きグランドは、前記導線路の前記長さ方向に複数個に分割され、それらのうち少なくとも入力側又は出力側の前記第2の分割浮きグランドと前記外部グランド電位との間に前記第2の受動2端子回路が接続された請求項9又は10記載のコモンモードフィルタ。
- 前記第2の分割浮きグランドは、隣り合う全て又は一部の前記分割浮きグランド間にも前記第2の受動2端子回路が接続された請求項9~11いずれか1記載のコモンモードフィルタ。
- 前記導線路は、前記第1の誘電体層としての誘電体基板に形成され、前記第1の分割浮きグランドは前記誘電体基板と異なる誘電体基板に形成されるとともに、第2の浮きグランドは前記第2の誘電体層としての誘電体基板に形成され、それら異なる前記誘電体基板が積層一体化されてなる請求項9~12いずれか1記載のコモンモードフィルタ。
- 前記第1および第2の受動2端子回路は、短絡線路である請求項1~13いずれか1記載のコモンモードフィルタ。
- 前記第1および第2の受動2端子回路は、1個以上の受動素子としてのインダクタンス、容量、抵抗、又はこれらの組合せである請求項1~13いずれか1記載のコモンモードフィルタ。
Priority Applications (4)
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US13/145,733 US8922303B2 (en) | 2009-07-27 | 2010-07-21 | Common mode filter |
JP2011524738A JP5386586B2 (ja) | 2009-07-27 | 2010-07-21 | コモンモードフィルタ |
CN201080020817.5A CN102422533B (zh) | 2009-07-27 | 2010-07-21 | 共模过滤器 |
EP10804289.6A EP2405573A4 (en) | 2009-07-27 | 2010-07-21 | COMMON MODE FILTER |
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JP2009-174199 | 2009-07-27 | ||
JP2009174199 | 2009-07-27 |
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PCT/JP2010/062208 WO2011013543A1 (ja) | 2009-07-27 | 2010-07-21 | コモンモードフィルタ |
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US (1) | US8922303B2 (ja) |
EP (1) | EP2405573A4 (ja) |
JP (1) | JP5386586B2 (ja) |
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JP2019096710A (ja) * | 2017-11-22 | 2019-06-20 | パナソニックIpマネジメント株式会社 | コモンモードフィルタ実装基板 |
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JP6282388B2 (ja) * | 2011-10-24 | 2018-02-21 | デクセリアルズ株式会社 | 静電容量素子、及び共振回路 |
US9219463B2 (en) * | 2013-02-06 | 2015-12-22 | Intel Corporation | Hybrid common mode choke |
WO2015158726A1 (de) | 2014-04-16 | 2015-10-22 | Leoni Kabel Holding Gmbh | Vorrichtung und verfahren zur signalübertragung von differentiellen datensignalen |
WO2015181883A1 (ja) * | 2014-05-27 | 2015-12-03 | 松江エルメック株式会社 | コモンモードフィルタ |
TWI562536B (en) | 2014-09-30 | 2016-12-11 | Wistron Corp | Common mode filter |
US9571059B2 (en) * | 2015-03-28 | 2017-02-14 | Intel Corporation | Parallel via to improve the impedance match for embedded common mode filter design |
KR101823236B1 (ko) * | 2016-04-22 | 2018-01-29 | 삼성전기주식회사 | 공통 모드 필터 |
DE112016007021B4 (de) | 2016-08-03 | 2023-08-17 | Mitsubishi Electric Corporation | Störschutzfilterschaltung |
US10212806B2 (en) | 2017-01-09 | 2019-02-19 | Laird Technologies, Inc. | Absorber assemblies having a dielectric spacer, and corresponding methods of assembly |
CN106849896A (zh) * | 2017-01-22 | 2017-06-13 | 合肥联宝信息技术有限公司 | 一种滤波器件和电子设备 |
CN114976609B (zh) * | 2021-02-26 | 2024-04-12 | 华为技术有限公司 | 一种印刷电路板及电子设备 |
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US20110279197A1 (en) | 2011-11-17 |
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CN102422533A (zh) | 2012-04-18 |
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US8922303B2 (en) | 2014-12-30 |
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