WO2011052374A1 - 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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- WO2011052374A1 WO2011052374A1 PCT/JP2010/067918 JP2010067918W WO2011052374A1 WO 2011052374 A1 WO2011052374 A1 WO 2011052374A1 JP 2010067918 W JP2010067918 W JP 2010067918W WO 2011052374 A1 WO2011052374 A1 WO 2011052374A1
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- Prior art keywords
- common mode
- differential
- differential delay
- mode filter
- series
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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—Balance/unbalance networks
- H03H7/425—Balance-balance networks
- H03H7/427—Common-mode filters
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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
- H03H7/01—Frequency selective two-port networks
- H03H7/075—Ladder networks, e.g. electric wave filters
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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
- H03H7/01—Frequency selective two-port networks
- H03H7/09—Filters comprising mutual inductance
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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
- H03H7/01—Frequency selective two-port networks
- H03H7/17—Structural details of sub-circuits of frequency selective networks
- H03H7/1708—Comprising bridging elements, i.e. elements in a series path without own reference to ground and spanning branching nodes of another series path
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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
- H03H7/01—Frequency selective two-port networks
- H03H7/17—Structural details of sub-circuits of frequency selective networks
- H03H7/1716—Comprising foot-point elements
- H03H7/1725—Element to ground being common to different shunt paths, i.e. Y-structure
-
- 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
- H03H7/01—Frequency selective two-port networks
- H03H7/17—Structural details of sub-circuits of frequency selective networks
- H03H7/1716—Comprising foot-point elements
- H03H7/1733—Element between different shunt or branch paths
-
- 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
- H03H7/01—Frequency selective two-port networks
- H03H7/17—Structural details of sub-circuits of frequency selective networks
- H03H7/1741—Comprising typical LC combinations, irrespective of presence and location of additional resistors
- H03H7/1766—Parallel LC in series path
Definitions
- the present invention relates to a common mode filter, and more particularly to a common mode filter that allows a desirable ultrahigh-speed differential signal propagating through an ultrahigh-speed differential line to pass while blocking undesirable common-mode noise and hardly causing electromagnetic interference.
- Patent Document 2 a configuration in which the lower limit of the frequency band of the normal mode signal is 2 MHz, as disclosed in Japanese Patent Application Laid-Open No. 2004-266634, or Japanese Patent Application Laid-Open No. 2000-58343 (Patent Document 2).
- Patent Document 2 Japanese Patent Application Laid-Open No. 2004-266634, or Japanese Patent Application Laid-Open No. 2000-58343
- an ideal common mode choke coil is composed of a pair of coils wound around a magnetic core and having a coupling coefficient close to “1”, as shown in the equivalent circuit of FIG.
- the transmission line is formed by the inter-coil capacitance with a low value, and the characteristic impedance is managed.
- the equivalent inductance inserted on the differential line has a large value with respect to the common mode noise, and the common mode noise is prevented from passing as shown by the symbol Scc21 in FIG. Is possible.
- the common mode choke coil has an inductance close to zero with respect to the differential signal (normal mode signal) and forms a low-loss transmission line in combination with the inter-line capacitance, the characteristic indicated by reference numeral Sdd21 in FIG. Pass with less loss.
- FIG. 12 is shown in order to set the passband to 15 GHz and to compare with the effect of the present invention.
- the above-described common mode choke coil has a large inductance, that is, a high series impedance with respect to the common mode noise and cuts it off, when the input terminal is viewed from the common mode noise, the inside of the input terminal is terminated.
- the common mode noise applied to the input terminal is close to the open state, and shows the same response as that of the open terminal line at the input terminal portion.
- the applied common mode noise and the reflected common mode noise reflected therefrom are superimposed, and the peak voltage of the common mode noise at the input terminal portion is likely to increase.
- the input terminal part is difficult to mount on an electronic device and shield it for easy connection, it is easy to radiate electromagnetic waves from here and can cause electromagnetic interference. An increase in the peak voltage of mode noise is not preferable.
- the inventor has already proposed a common mode filter capable of temporally dispersing reflected common mode noise according to Japanese Patent Application No. 2009-220549. According to this common mode filter, the peak voltage of the reflected common mode noise can be suppressed to a low level. Further, a configuration capable of eliminating the power of the reflected common mode noise has been found, and the present invention has been completed. .
- the present invention has been made to solve such a problem, and can ensure the transmission of an ultra-high-speed differential signal in an ultra-high-speed differential line and can extinguish the power of reflected common mode noise. It aims at providing the common mode filter which is hard to cause.
- a common mode filter includes a passive series element including an inductor arranged in series in a differential line and a parallel arrangement between the differential lines.
- the lumped constant differential delay line has a constant K type configuration.
- the lumped constant differential delay line has an induction m-type configuration.
- the lumped constant differential delay line has an all-pass configuration.
- a common mode filter comprising the lumped constant differential delay line and the noise attenuating passive two-terminal circuit as a differential delay element of one section, and the differential delay element is a ladder on the differential line.
- a plurality of sections are arranged in series and are configured by a plurality of sections.
- the common mode filter according to claim 6 of the present invention is configured by arranging lumped constant differential delay lines in series in a ladder shape between the differential delay elements.
- the common mode filter according to claim 7 of the present invention is configured such that a resistor is connected between connection points of the capacitors in the lumped constant differential delay line of the plurality of sections.
- the common mode filter according to claim 8 of the present invention is configured such that only a common mode attenuation inductor is connected between a connection point between capacitors and a ground potential in some of the lumped constant differential delay lines. Yes.
- the lumped constant differential delay line is composed of two or three different differential delay elements of the constant K type, induction m type and all-pass type. Configured.
- a common mode filter according to a tenth aspect of the present invention is configured by changing the constant of the passive two-terminal circuit for noise attenuation in the differential delay element for each section.
- a lumped constant differential delay line in which an inductor is disposed as a passive series element and a capacitor is disposed as a passive parallel element, and the capacitor as the parallel element is the capacitor. Is formed of two capacitors connected in series that are equal in value to each other, and a resistor for attenuating common mode noise between a connection point of the capacitors connected in series and the ground potential, and a series of an inductor and a resistor.
- the lumped constant differential delay line is configured as an induction m type, the above-described effect can be obtained in the induction m type configuration.
- the differential delay line and the noise attenuating inductor are used as a differential delay element of one section, and a plurality of differential delay elements are arranged in series on the differential line in a ladder shape. Since it is composed of a plurality of sections, it is possible to obtain various characteristics in addition to the effects described above.
- lumped constant differential delay lines are arranged in series in a ladder shape between the differential delay elements, so that various characteristics are obtained in addition to the above-described effects. It is possible.
- the common mode filter according to claim 7 of the present invention is configured by connecting resistors between a plurality of connection points of the capacitors in the differential delay line of the plurality of sections, in addition to the effects described above. Thus, various characteristics can be obtained.
- the common mode attenuation inductor is connected between the connection point between the capacitors and the ground potential in some of the lumped constant differential delay lines. Furthermore, it is easy to obtain various characteristics.
- the common mode filter according to claim 10 of the present invention since the constant of the passive two-terminal circuit for noise attenuation in the differential delay element is made different, it is easy to form the pass characteristic of the common mode noise to a desired characteristic, Furthermore, it is possible to obtain various characteristics such as the absorption characteristic of common mode noise to a desired characteristic, and it is difficult to reliably cause electromagnetic interference.
- FIG. 1 is a circuit diagram showing a first embodiment of a common mode filter according to the present invention. It is a transmission characteristic figure of the common mode filter of this invention shown in FIG.
- FIG. 3 is a power distribution characteristic diagram of the common mode filter of the present invention shown in FIG. 2.
- FIG. 6 is a pass characteristic diagram of the common mode filter of the present invention shown in FIG. 5.
- FIG. 6 is a power distribution characteristic diagram of the common mode filter of the present invention shown in FIG. 5.
- FIG. 1 It is a circuit diagram which shows 3rd Embodiment of the common mode filter which concerns on this invention. It is a transmission characteristic figure of the common mode filter of this invention shown in FIG. It is an electric power distribution characteristic figure of the common mode filter of this invention shown in FIG. This is an equivalent circuit of a conventional common mode choke coil. It is a passage characteristic figure of the conventional common mode choke coil shown in FIG. It is an electric power distribution characteristic figure of the conventional common mode choke coil shown in FIG.
- FIG. 1 is a circuit diagram showing an example of a lumped constant differential delay line applied to a common mode filter according to the present invention.
- a ladder-type differential four-terminal network 5 is formed on the differential lines 1 and 3 between the differential input terminals 1A and 1B and the differential output terminals 2A and 2B.
- the ladder-type differential four-terminal network 5 is a combination of passive series elements arranged in series in the differential lines 1 and 3 and passive parallel elements arranged in parallel between the differential lines 1 and 3. Connected and configured in a ladder shape.
- a plurality of, for example, three inductors Lo as passive series elements are connected in series.
- Capacitors Co / 4 and Co / 2 as passive parallel elements are connected to both ends of each inductor Lo.
- Capacitors Co / 4 and Co / 2 are connected between both ends of each inductor Lo at the same position in the differential lines 1 and 3, and a constant K ⁇ type lumped constant differential delay line DL having three sections is formed. Yes.
- the differential delay elements dl1, dl2, and dl3 for one section in the lumped constant differential delay line DL are ladder-type differential four-terminal circuits, and a pair of inductors Lo in the differential lines 1 and 3 and 2 at both ends thereof. It is formed by capacitors Co / 4 and Co / 2. Adjacent differential delay elements dl1 and dl2 and capacitors Co / 2 of dl2 and dl3 are shared.
- Equation 1 The delay time td of each of the differential delay elements dl1 to dl3 is expressed as “Equation 1”.
- the capacitance of one section of the differential delay elements dl1 to dl3 is also expressed as Co / 4 and Co / 2, so that the expression of the delay time td is generally expressed in a single-end delay line. Match.
- the symbols + vd and ⁇ vd on the differential input terminals 1A and 1B are a differential power source having an impedance Zo
- the symbol Zo on the differential output terminals 2A and 2B is a terminal impedance.
- FIG. 2 is a circuit diagram illustrating a first configuration according to the common mode filter of the present invention, which is an improvement of the lumped constant differential delay line of FIG. Reference Vc is a common mode noise source.
- Capacitors Co / 4 and Co / 2 connecting between both ends of the pair of inductors Lo on the differential lines 1 and 3 in each of the differential delay elements dl1 to dl3 of FIG. 1 described above are connected in series as shown in FIG. It is divided into two capacitors Co / 2 and Co / 2, or Co and Co. Moreover, the series combined capacitance of the capacitors Co / 2 and Co / 2 is equivalent to the capacitor Co / 4, and similarly, the series combined capacitance of the capacitors Co and Co is equivalent to the capacitor Co / 2.
- the capacitance of the two divided capacitors Co / 2 and Co has twice the capacitance value of the one capacitor Co / 4 and Co / 2 before the division.
- each of the differential delay elements dl1 to dl3 there is a common mode noise attenuation between the capacitors Co / 2 and Co / 2, or between the connection points T1, T2, T3 and T4 of Co and Co and the ground potential.
- a passive two-terminal circuit in which L1 and R1, L2 and R2, L3 and R3, and L4 and R4 are connected in series is connected.
- the common mode noise attenuating inductors L1 to L4 form a series resonance circuit by a combination with the capacitors Co / 2 and Co connected to the inductors L1 to L4, respectively, and this resonance frequency is set to the common mode noise attenuation pole frequency.
- the attenuation pole since the Q of the series resonant circuit is lowered by the resistors R1 to R4, the attenuation pole has a shallow broad shape or does not appear clearly.
- Other configurations are the same as in FIG.
- the ladder-type differential four-terminal network 5 formed in the differential lines 1 and 3 includes the lumped constant-type differential delay elements dl1 to dl3 which are the ladder-type four-terminal circuits described above. It is possible to pass a differential signal propagating through the differential lines 1 and 3 with an amplitude characteristic and a group delay characteristic as designed.
- the differential signals transmitted through the differential lines 1 and 3 are opposite phase signals, so that they reach the connection points T1 to T4 between the capacitors Co / 2 and Co. Even if they cancel each other, they disappear.
- the series resonance circuit does not contribute to the differential signal, and the differential signal is transmitted without deterioration as designed by the differential delay elements dl1 to dl3.
- two capacitors Co / 2 and Co which are parallel elements forming the differential delay elements dl1 to dl3, and a common mode noise attenuating inductor connected to these connection points T1 to T4 Since a series resonant circuit for common mode noise is formed by L1 to L4, the common mode noise is attenuated and cut off, and it is easy to attenuate the common mode noise as designed, and the resistors R1 to R4 are Reduce the Q of the series resonant circuit to consume and absorb common mode noise.
- the amount of absorption of common mode noise is the largest near the common mode noise attenuation pole frequency, and the amount of absorption decreases at other frequencies, so unabsorbed common mode noise is attenuated and cut off to become reflected common mode noise.
- the differential input terminals 1A and 1B since the reflected common mode noise propagates through the differential delay elements dl1 to dl3 and returns to the differential input terminals 1A and 1B with a double propagation delay time in a round trip, the differential input terminals 1A and 1B The applied common mode noise and the reflected common mode noise are superposed with their phases shifted.
- the reflected common mode noise is not absorbed by the resistors R1 to R4, the peak voltage rise of the common mode noise is reduced at the differential input terminals 1A and 1B, and the noise at the differential input terminals 1A and 1B is reduced. Is not easily radiated.
- FIG. 3 is a characteristic diagram of the common mode filter of the present invention shown in FIG. 2.
- symbol Sdd21 is a differential signal passing characteristic
- symbol Scc21 is a common mode noise passing characteristic.
- the characteristics shown in FIG. 3 are a third harmonic component of the 2.5 GHz clock assuming that the delay time of one section is 30 ps and the differential impedance is 100 ⁇ , and common mode noise is removed from the 2.5 GHz differential clock.
- the constant of each element is set so that the pass band for the differential signal is about 10 GHz so that the frequency component of 5 GHz can pass sufficiently, and further the attenuation of common mode noise is about 18 dB at 2.5 GHz.
- the power of the common mode noise input to the ladder-type differential four-terminal network 5 is assumed to be 100%, and it passes through each frequency.
- the ratio of the power to be reflected, the ratio of the reflected power and the ratio of the absorbed power were determined.
- FIG. 4 shows the ratio of the passage, reflection and absorption of the common mode noise power input to the common mode filter according to the present invention of FIG. It can be seen that the power absorption peak is set in the vicinity of 2.5 GHz, which is suitable for removing the common mode noise of the 2.5 GHz differential clock.
- Such a structure is effective for removing common mode noise of a specific frequency.
- the constants of the inductors L1 to L4 and the resistors R1 to R4 are set for each section. Set and adjust.
- FIG. 13 shows the ratio of passing, reflection and absorption of the common mode noise power input to the ideal common mode choke coil shown in FIG. It can be seen that in the conventional common mode choke coil, most of the input common mode noise power is reflected by interruption, and about 90% of the input power is reflected.
- the inductors L1 to L4 are formed of a metal conductor having a high resistivity such as nichrome, a series resistance component is generated in the inductors L1 to L4 themselves even if the resistors R1 to R4 are not connected. The same effect as connecting R1 to R4 can be obtained.
- FIG. 5 shows a second embodiment of the common mode filter according to the present invention, which is based on an induction mT type lumped constant differential delay line having four sections.
- the inductor Lo forming the passive series element is divided into two equal parts, and the two equally divided inductors Lo / 2 are connected in series and mutually induced m
- the connection points of the inductors Lo / 2 that are coupled and divided into two equal parts are connected by the above-described series circuit of capacitors.
- Other configurations are the same as those in FIG.
- each differential four-terminal circuit is converted into a series circuit of two capacitors Co and Co having a double capacitance value, and a connection point T1 between the capacitors Co connected in series.
- T2, T3, T4 and the above-described common mode noise attenuating inductors L1 to L4 are connected between the ground potential. This is equivalent to setting the common mode noise attenuation resistors R1 to R4 in FIG. 2 to 0 ⁇ .
- resistors R12, R23 and R34 are connected between the connection points T1 and T2, between T2 and T3 and between T3 and T4, and resistors R10 and R40 are connected between the connection point T1 and ground and between the connection point T4 and ground. is there.
- the passive two-terminal circuit for noise attenuation is configured with a complicated path.
- the passive two-terminal circuit connected to the contact T1 not only the parallel circuit of the inductor L1 and the resistor R10 but also various paths connected to the ground via R12 are additionally connected to the parallel circuit.
- the inductor constituting the passive series element of the ladder-type differential four-terminal network 5 is equivalent to (Lo + 2m), and the passive parallel element is equivalent to the capacitor Co and the negative inductor component ( ⁇ m). Are connected in series.
- FIG. 6 is a characteristic diagram of the common mode filter shown in FIG. 5.
- symbol Sdd21 is a differential signal passing characteristic
- symbol Scc21 is a common mode noise passing characteristic
- a delay time of one section is 37.5 ps.
- the constant of each element is determined so that the differential impedance is 100 ⁇ .
- the differential signal passing characteristic Sdd21 shows characteristics similar to those in FIG. 3, while the common mode noise passing characteristic Scc21 has an attenuation of about 15 dB at 2.5 GHz or more, and in a wider frequency range than FIG. Greater reduction is obtained.
- FIG. 7 shows the power distribution ratio of passing, reflecting, and absorbing with respect to the input common mode noise power. As can be seen from FIG. 7, the configuration shown in FIG. 5 exhibits absorption of 60% to 70% at 2.5 GHz or higher, and does not have an absorption peak at a specific frequency as shown in FIG.
- FIG. 8 shows a third embodiment according to the common mode filter of the present invention.
- the differential delay elements dl1 to dl4 are composed of four differential delay elements dl1 to dl4.
- the inductor Lo that forms the passive series element is divided into two equal parts, and the inductors Lo / 2 divided into two equal parts are used.
- the inductors Lo / 2 connected in series are connected in series and mutually inductively coupled to each other, and both ends of the inductor Lo / 2 connected in series are bridged by a capacitor Ca.
- a capacitor Ca has a configuration of an all-pass lumped constant differential delay line. Other configurations are the same as those in FIG.
- the inductor that constitutes the passive series element of the ladder-type differential four-terminal circuit is equivalent to the inductor that determines the delay time of one section (Lo + 2m), and the parallel element is equivalently negative with the capacitor Co.
- the inductor component ( ⁇ m) is connected in series.
- the parallel element is converted into a series connection of two capacitors having double capacitance values, and the connection points of the two capacitors Co connected in series are sequentially connected from the differential input terminals 1A and 1B to T1, T2, T3 and T4, resistors R12, R23 and R34 between these connection points T1 and T2, between T2 and T3 and between T3 and T4, and between the connection point T1 and ground and between the connection point T4 and ground R10 and R40.
- resistors R12, R23 and R34 between these connection points T1 and T2, between T2 and T3 and between T3 and T4, and between the connection point T1 and ground and between the connection point T4 and ground R10 and R40.
- the delay time td of one section in each of the differential delay elements dl1 to dl4 having this configuration is expressed by “Formula 6”.
- the differential impedance Zd in each of the differential delay elements dl1 to dl4 is expressed by “Expression 7”.
- FIG. 9 is a characteristic diagram of the common mode filter shown in FIG. 8.
- Reference numeral Sdd21 is a differential signal passing characteristic and reference numeral Scc21 is a common mode noise passing characteristic.
- the characteristic of FIG. 9 is an example in which the constant of each element is determined so that the delay time of one section is 50 ps and the differential impedance is 100 ⁇ .
- the coupling coefficient is preferably set to a value larger than that of the induction m type.
- the bridging capacitance Ca is arranged, when the coupling coefficient k is 0.4, the bridging capacitance Ca is about 1/10 of the capacitor Co.
- the common mode noise that reaches each of the connection points T1 to T4 tries to return to the ground via the resistors R10 to R40, so that power is absorbed by these resistors R10 to R40 at that time.
- the passage characteristics of the common mode noise slightly change depending on the values of the resistors R10 to R40, but the delay time of the differential delay elements dl1 to dl4 is greatly influenced by the delay time of the differential delay elements dl1 to dl4. As the value increases, the passage of common mode noise from a lower frequency can be prevented.
- FIG. 9 shows the differential signal passing characteristic Sdd21 and the common mode noise passing characteristic Scc21 in the common mode filter having the configuration of FIG. 8 according to the present invention
- FIG. 10 shows the common mode noise input to the common mode filter having the configuration of FIG. Shows the power distribution ratio of transmission, reflection and absorption with respect to the power.
- the common mode pass characteristic Scc21 has an attenuation start frequency shifted to the high frequency side because the pass characteristics cannot be formed by the common mode noise attenuating inductors L1 to L4, compared to the configurations of FIGS. When compared at 2.5 GHz, only about 12 dB attenuation is obtained.
- the absorption amount of the common mode noise power is 70% or more in the frequency range of 2.2 GHz to 8.7 GHz. As a result, a broader absorption peak is obtained than in other structures.
- the differential signal passing characteristic Sdd21 has a loss of almost 0 dB in FIG. 9, and the all-pass lumped constant delay line is optimal for the purpose of passing an ultrahigh-speed signal in the GHz band.
- the resistance connected between the contacts of the connection points T1 to T4 does not necessarily need to be between the contacts in the adjacent sections, and may be connected between the contacts separated by two or more sections. .
- common mode filters having different configurations have been exemplified using three types of lumped constant differential delay lines of constant K type, induction m type, and all-pass type, but all lumped constant differential delay lines have been exemplified. Can be applied to common mode filters of all configurations.
- the lumped constant differential delay line has been described with three types of constant K type, induction m type and all-pass type, but other configurations are possible.
- induction m type has mutual induction in an adjacent section of an inductor that is a series element of a ladder type differential delay line, although not illustrated, mutual induction is provided between inductors in a section separated by two or more sections.
- the configuration according to the present invention can be applied even in such a configuration, and the same effect can be obtained.
- the lumped-constant differential delay line is, for example, two constant K-type differential delay elements and three inductive m-type differentials among the constant K-type, induction m-type and all-pass type differential delay elements.
- the object of the present invention can be achieved with a configuration in which two or three different delay elements are combined, such as connecting delay elements in a ladder shape.
- this group delay flat type low-pass filter is similar to the constant K type at first glance, but in a configuration consisting of a plurality of sections, an inductor and a passive parallel device that are passive series elements when configured with a single end. Since the values of certain capacitors are all different, it becomes complicated when commercializing.
- the common mode filter of the present invention is configured to include a differential delay line that includes a ladder-type differential four-terminal circuit including an inductor as the passive series element and a capacitor as the passive parallel element. Passes the desired ultra-high-speed differential signal propagating through the ultra-high-speed differential transmission line, while attenuating undesired common mode noise without passing it, and absorbing reflected common mode noise to suppress its peak value Thus, it is possible to suppress the electromagnetic radiation intensity of the blocked reflected common mode noise.
- the lumped constant differential delay line in FIG. 5 may be configured with only one section of the induction mT type, and one attenuation pole frequency may be matched with the frequency of the common mode noise.
- common mode filter of the present invention when a plurality of sections are formed, conventional differential delay lines, for example, inductors L1 to L4 for attenuating common mode noise and resistors R1 to R40 are omitted in some sections. Configuration is also possible.
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Abstract
Description
図7には、入力されたコモンモードノイズの電力に対する通過、反射および吸収の電力分配比率を示す。図7から分かるとおり、図5に示す構成は、2.5GHz以上で60%~70%の吸収を示し、図4に示すような特定の周波数での吸収ピークを持たないことが分かる。
1A、1B 差動入力端子(入力側)
2A、2B 差動出力端子(出力側)
5 梯子型差動4端子網
Co、Co/2、Co/4、Ca キャパシタ
DL 集中定数差動遅延線
dl1、dl2、dl3、dl4 差動遅延素子(差動4端子回路)
Lo、Lo/2 インダクタ
L1、L2、L3、L4 コモンモードノイズ減衰用インダクタ(ノイズ減衰用受動2端子回路)
R1、R2、R3、R4、R10、R12、R23、R34、R40 コモンモードノイズ減衰用抵抗(ノイズ減衰用受動2端子回路)
T1、T2、T3、T4 接続点
+vd、-vd 差動電源
Vc コモンモードノイズ源
Claims (10)
- 差動線路中に直列的に配置されたインダクタを含む受動直列素子および前記差動線路間に並列的に配置されたキャパシタを含む受動並列素子からなる梯子型の差動4端子回路を有してなる集中定数差動遅延線であって、前記キャパシタが、当該キャパシタと等価にして値の等しい2個の直列接続されたキャパシタからなる集中定数差動遅延線と、
直列接続された前記キャパシタどうしの接続点とグランド電位との間に接続され、コモンモードノイズ減衰用の抵抗、インダクタと抵抗の直列回路、又はインダクタと抵抗の並列回路からなるノイズ減衰用受動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。 - 前記集中定数差動遅延線は、定K型構成である請求項1記載のコモンモードフィルタ。
- 前記集中定数差動遅延線は、誘導m型構成である請求項1記載のコモンモードフィルタ。
- 前記集中定数差動遅延線は、全域通過型構成である請求項1記載のコモンモードフィルタ。
- 前記集中定数差動遅延線および前記ノイズ減衰用受動2端子回路を1区間の差動遅延素子とし、前記差動線路に前記差動遅延素子が梯子型に複数直列配置され複数区間が構成された請求項1~4いずれか1記載のコモンモードフィルタ。
- 上記差動遅延素子の間に前記集中定数差動遅延線が梯子状に直列配置されて構成された請求項5記載のコモンモードフィルタ。
- 前記複数区間の前記集中定数差動遅延線における前記キャパシタどうしの複数の接続点間に、抵抗が接続された請求項5又は6記載のコモンモードフィルタ。
- 一部の前記集中定数差動遅延線における前記キャパシタどうしの接続点とグランド電位との間に、コモンモード減衰用インダクタのみが接続された請求項5又は6記載のコモンモードフィルタ。
- 前記集中定数差動遅延線は、定K型、誘導m型および全域通過型の差動遅延素子中から異なる2個又は3個を複合した構成である請求項5~8いずれか1記載のコモンモードフィルタ。
- 前記差動遅延素子における前記ノイズ減衰用受動2端子回路の定数を区間毎に異ならせてなる請求項5~9いずれか1記載のコモンモードフィルタ。
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CN201080026928.7A CN102474235B (zh) | 2009-11-02 | 2010-10-13 | 共模滤波器 |
US13/376,094 US8847705B2 (en) | 2009-11-02 | 2010-10-13 | Common mode filter |
JP2011538334A JP5341201B2 (ja) | 2009-11-02 | 2010-10-13 | コモンモードフィルタ |
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Cited By (2)
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US10038421B2 (en) | 2014-05-27 | 2018-07-31 | Elmec Corporation | Common mode filter |
WO2023153283A1 (ja) * | 2022-02-09 | 2023-08-17 | 株式会社村田製作所 | フィルタ装置、高周波モジュール、および通信装置 |
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JP5352881B2 (ja) * | 2009-09-25 | 2013-11-27 | 松江エルメック株式会社 | コモンモードフィルタ |
US9875841B2 (en) * | 2013-04-24 | 2018-01-23 | Applied Energy Llc | Systems and methods for a DC phaseback choke |
TWI530093B (zh) * | 2014-05-02 | 2016-04-11 | 國立臺灣大學 | 共模雜訊抑制電路 |
US10018716B2 (en) * | 2014-06-26 | 2018-07-10 | Honeywell International Inc. | Systems and methods for calibration and optimization of frequency modulated continuous wave radar altimeters using adjustable self-interference cancellation |
JP6471619B2 (ja) * | 2015-06-12 | 2019-02-20 | 株式会社デンソー | 電子装置 |
KR101968585B1 (ko) * | 2016-02-05 | 2019-04-12 | 주식회사 아모텍 | 차동 및 공통 모드 겸용 필터 |
US10333410B2 (en) * | 2016-09-15 | 2019-06-25 | Futurewei Technologies, Inc. | Common-mode (CM) electromagnetic interference (EMI) reduction in resonant converters |
TWI692145B (zh) * | 2016-11-04 | 2020-04-21 | 國立臺灣大學 | 共模訊號吸收器及其等效電路 |
US10499489B2 (en) | 2017-07-14 | 2019-12-03 | Hewlett Packard Enterprise Development Lp | Defected ground structure with void having resistive material along perimeter to improve EMI suppression |
TWI731806B (zh) * | 2020-10-16 | 2021-06-21 | 安波科技股份有限公司 | 共模雜訊濾波器 |
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CN102474235B (zh) | 2015-06-10 |
CN102474235A (zh) | 2012-05-23 |
US8847705B2 (en) | 2014-09-30 |
JP5341201B2 (ja) | 2013-11-13 |
JPWO2011052374A1 (ja) | 2013-03-21 |
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