CN207853756U - A kind of bandwidth DC filtering circuit and device based on lead terminal - Google Patents

Abstract

The utility model is related to field of electromagnetic compatibility, and in particular to a kind of bandwidth DC filtering circuit based on lead terminal.Lead terminal includes terminal input terminal and terminal output end, it is characterised in that：The bandwidth DC filtering circuit includes first order capacitor filtering sub-circuit, second level common mode inductance filtering sub-circuit and the third level capacitor filtering sub-circuit for being arranged between terminal input terminal and terminal output end and setting gradually.The utility model further relates to a kind of device based on bandwidth DC filtering circuit.The utility model filters sub-circuit by being arranged between the input terminal and output end of lead terminal for filtering out the second level common mode inductance of 30MHz following frequencies noises, and.Filter out the first order capacitor filtering sub-circuit of noise and third level capacitor filtering sub-circuit in 30MHz 2.5GHz frequency ranges, effective filtering bandwidth span is sufficiently large, equal noise suppression effect that can be certain from the range of KHz to GHz range, filtering frequency range can cover the EMI test frequency ranges of Most electronic product, and application field is extensive.

Description

A kind of bandwidth DC filtering circuit and device based on lead terminal

Technical field

The utility model is related to field of electromagnetic compatibility, and in particular to a kind of bandwidth DC filtering circuit based on lead terminal And device.

Background technology

As electronic product is intelligent, the development of high speed, electromagnetic compatibility has become the one of examination Quality of electronic products Item important indicator.Definition according to international electronical commission standard IEC to electromagnetic compatibility includes mainly EMI (Electromagnetic Launching) With EMS (electromagnetic immunity) two parts.The electromagnetic noise of different frequency can by electronic equipment peripheral leads between line conduct or For the form of spatial emission to external radiation, these peripheral leads include power cord, signal wire etc..Therefore, it is filtered in lead terminal Wave is particularly important for the Electro Magnetic Compatibility of electronic equipment.

The frequency range that electromagnetic compatibility test is related to is wider, and range is in 9KHz-6GHz, and Most electronic products noise The exceeded frequency range spans of EMC are all very big.Especially since electronic product performance develops toward high speed now, therefore electromagnetism Compatible exceeded frequency range toward up GHz, and in most cases single filtering device can filter out noise frequency range it is very limited, have Effect filtering bandwidth span only arrives hertz up to a hundred.

How electromagnetic interference is effectively reduced, reach electromagnetic compatibility standard, is those skilled in the art's primary study always One of problem.

Utility model content

The technical problem to be solved by the present invention is to for the drawbacks described above of the prior art, provide one kind and be based on drawing The bandwidth DC filtering circuit of line terminals overcomes in existing filtering technique means because of material factor or itself limitation, Zhi Nengzhen There is the problem of EMI filter effects to narrow frequency range more.

Technical solution adopted by the utility model to solve its technical problems is：A kind of bandwidth based on lead terminal is provided DC filtering circuit, lead terminal include terminal input terminal and terminal output end, and the bandwidth DC filtering circuit includes setting Between terminal input terminal and terminal output end and set gradually first order capacitor filtering sub-circuit, the second level common mode inductance filter Marble circuit and third level capacitor filtering sub-circuit.

Wherein, preferred version is：The second level common mode inductance filtering sub-circuit includes a MnZn common mode inductance, the manganese The input terminal of zinc common mode inductance is connect with terminal input terminal, and output end is connect with terminal output end.

Wherein, preferred version is：The first order capacitor filtering sub-circuit includes the first BDL capacitances, the first BDL electricity Two electrodes held are connect with the input terminal of common mode inductance respectively, are also connect with terminal input terminal, the poles G of the first BDL capacitances Ground connection.

Wherein, preferred version is：The second level capacitor filtering sub-circuit includes the 2nd BDL capacitances, the 2nd BDL electricity Two electrodes held are connect with the output end of common mode inductance respectively, are also connect with terminal output end, the poles G of the 2nd BDL capacitances Ground connection.

Wherein, preferred version is：Described includes circuit board and shielding case, and the shielding case includes a cavity, the circuit Plate setting is in the cavity and the poles G of the first BDL capacitances and the 2nd BDL capacitances are connect with shielding case.

Wherein, preferred version is：The poles G of the first BDL capacitances and the 2nd BDL capacitances are in the form of low ESL and shielding Cover connection.

Wherein, preferred version is：Capacitance >=1uF of first BDL capacitances of the first order capacitor filtering sub-circuit 13, institute State inductance value >=1mH of the common mode inductance of second level common mode inductance filtering sub-circuit 14, the third level capacitor filtering sub-circuit Appearance value≤100pF of 15 the 2nd BDL capacitances.

Technical solution adopted by the utility model to solve its technical problems is：A kind of device is provided, described device includes Ontology, and the bandwidth DC filtering circuit of the power end or control terminal in ontology is set, externally fed power supply is straight by bandwidth Stream filter circuit is connect with power end or external control module is connect by bandwidth DC filtering circuit with control terminal.

Wherein, preferred version is：The two input connecting pin of power end or control terminal setting of described device, the bandwidth direct current The jack of the output end setting of filter circuit and input connecting pin cooperation, the circuit board of the bandwidth DC filtering circuit passes through defeated The cooperation for entering connecting pin and jack is fixed on such devices.

Wherein, preferred version is：Described device further includes shielding case, and the shielding case includes a cavity, and the bandwidth is straight It flows filter circuit setting in the cavity, multiple through-holes, the input of the bandwidth DC filtering circuit is provided on the shielding case End and output end are extended by corresponding through-hole outside shielding case and shielding case fitting is arranged on the shell of ontology.

Wherein, preferred version is：The shielding case is connect by the cage connection of conducting foam or conducting wire and ontology Ground.

The beneficial effects of the utility model are that compared with prior art, the utility model passes through in the defeated of lead terminal Enter setting between end and output end and filters sub-circuit for filtering out the second level common mode inductance of 30MHz following frequencies noises, and. The first order capacitor filtering sub-circuit and third level capacitor filtering sub-circuit of noise in 30MHz-2.5GHz frequency ranges are filtered out, is effectively filtered Wave bandwidth span is sufficiently large, and from the range of KHz to GHz range, the certain noise suppression effect of energy, filtering frequency range can cover absolutely The EMI test frequency ranges of most of electronic product, application field are extensive.

Description of the drawings

Below in conjunction with accompanying drawings and embodiments, the utility model is described in further detail, in attached drawing：

Fig. 1 is the circuit diagram of the utility model bandwidth DC filtering circuit；

Fig. 2 is the electrical block diagram of the utility model first order capacitor filtering sub-circuit；

Fig. 3 is the structural schematic diagram of the utility model motor；

Fig. 4 is the structural schematic diagram one of bandwidth DC filtering circuit of the utility model based on shielding case；

Fig. 5 is the structural schematic diagram two of bandwidth DC filtering circuit of the utility model based on shielding case.

Specific implementation mode

In conjunction with attached drawing, elaborate to the preferred embodiment of the utility model.

As depicted in figs. 1 and 2, the utility model provides a kind of the preferred of the bandwidth DC filtering circuit based on lead terminal Embodiment.

A kind of bandwidth DC filtering circuit based on lead terminal, lead terminal include terminal input terminal 11 and terminal output End 12, the bandwidth DC filtering circuit includes being arranged between terminal input terminal 11 and terminal output end 12 and setting gradually First order capacitor filtering sub-circuit 13, second level common mode inductance filtering sub-circuit 14 and third level capacitor filtering sub-circuit 15.

Wherein, lead terminal includes two terminal input terminals 11 and two terminal output ends 12, first order capacitor filtering Circuit 13 is arranged between two terminal input terminals 11, and second level common mode inductance filters the setting of sub-circuit 14 and inputted in two terminals Between end 11 and two terminal output ends 12, third level capacitor filtering sub-circuit 15 is arranged between two terminal output ends 12, Form one or four terminal filter circuits.

Wherein, lead terminal can be applicable to Switching Power Supply DC terminal, direct current generator and low-frequency transmission rate differential signal etc. Field.Specifically, from the incident electric signal of terminal input terminal 11, pass through first order capacitor filtering sub-circuit 13 and third level capacitance Sub-circuit 15 is filtered into line noise filter, the noise in 30MHz-2.5GHz frequency ranges is filtered out, again by second level common mode inductance Sub-circuit 14 is filtered into line noise filter, filters out 30MHz following frequencies noises, to realize that effect filtering bandwidth span is sufficiently large, Filtering frequency range can cover the EMI test frequency ranges of Most electronic product.

In the present embodiment, the second level common mode inductance filtering sub-circuit 14 includes a common mode inductance, the common mode electricity The input terminal of sense is connect with terminal input terminal 11, and output end is connect with terminal output end 12.

Wherein, common mode inductance (Common mode Choke), is also common mode choke, is usually used in the Switching Power Supply of computer The electromagnetic interference signal of middle filtering common mode.In board design, common mode inductance is also to play EMI filtering, for inhibiting high The electromagnetic wave outside radiation-emitting that velocity signal line generates.Two coils are wound on same iron core, the number of turns and all identical (coiling of phase Reversely).In this way, when the normal current in circuit flows through common mode inductance, electric current generates in the inductance coil of same-phase coiling Reversed magnetic field and cancel out each other, normal signal electric current is mainly influenced by coil resistance (and on a small quantity caused by leakage inductance at this time Damping)；When coil midstream crosses the electric current of common mode interference, the sense that generate magnetic field in the same direction in coil and increase coil is understood It is anti-, so that coil is shown as high impedance, generate stronger damping, with this attenuation common-mode electric current, achievees the purpose that filtering.

Preferably, the common mode inductance is MnZn common mode inductance, and the filtering frequency range of MnZn material common mode inductance is relatively low general Sub- 10Mhz hereinafter, the filtering frequency range of first order capacitor filtering sub-circuit 13 and third level capacitor filtering sub-circuit 15 be high frequency, two Person combines so that the bandwidth span of filter is very big.

In the present embodiment, the first order capacitor filtering sub-circuit 13 includes the first BDL capacitances, the first BDL electricity Two electrodes held are connect with the input terminal of common mode inductance respectively, are also connect with terminal input terminal 11, the G of the first BDL capacitances Pole is grounded.

Specifically, the first BDL capacitor filtering frequency ranges belong to high frequency, are a kind of capacitances of four terminals, left and right ends connect Signal, intermediate both ends are the poles G, and two poles G are for being grounded.Specifically：Including electrode 131, electrode 132, the poles G 133 and the poles G 134. Wherein, electrode 131 and electrode 132 are connect with the both ends of terminal input terminal 11 respectively, and the poles G 133 and the poles G 134 are grounded.

Wherein, for BDL capacitances after carrying out the measure of the both ends poles G ground connection, itself parasitic inductance and dead resistance all can be very low (i.e. ESL and ESR are very low), and the filtering bandwidth of BDL capacitances is 4 to 5 times wider than general capacitance.

And the second level capacitor filtering sub-circuit includes the 2nd BDL capacitances, two electrodes of the 2nd BDL capacitances It connect with the output end of common mode inductance, is also connect with terminal output end 12 respectively, the poles the G ground connection of the 2nd BDL capacitances.Its In, as soon as the structure of the 2nd BDL capacitances is consistent with BDL capacitances, do not illustrate one by one herein.

In the present embodiment, described includes circuit board and shielding case, and the shielding case includes a cavity, and the circuit board is set It sets in the cavity and the poles G of the first BDL capacitances and the 2nd BDL capacitances is connect with shielding case.Specifically, circuit board packet Mounting hole is included, circuit board is mounted in the cavity of shielding case by mounting hole by screw or other fixation kits.

Wherein, shielding case is metallic shield.

Wherein, the poles G are connected to by the form of low ESL in shielding case." ESL " refers to parasitic inductance, any filter All inevitably there is a problem of that ESL is excessively high when high frequency.There are many ESL Producing reasons：1, filter external lead wire It is long；The reason of 2 filter internal structure；3, filter ground connection is imperfect.Here it refers to shortening lead, before carrying out filtering Ground connection.

In the present embodiment, formula is calculated according to resonant frequency：F=1/ (2* π * √ LC)；First order capacitor filtering electricity Capacitance >=1uF of the first BDL capacitances on road 13, second level common mode inductance filter sub-circuit 14 common mode inductance inductance value >= 1mH, appearance value≤100pF of the 2nd BDL capacitances of third level capacitor filtering sub-circuit 15.

The utility model provides a kind of preferred embodiment of device.

A kind of device, described device include ontology, and the bandwidth direct current filter of the power end or control terminal in ontology is arranged Wave circuit, externally fed power supply is connect with power end by bandwidth DC filtering circuit or external control module passes through bandwidth DC filtering circuit is connect with control terminal.

Preferably, two input connecting pin of the power end of described device or control terminal setting, the bandwidth DC filtering circuit Output end setting and input connecting pin cooperation jack, the circuit board of the bandwidth DC filtering circuit, which passes through, inputs connecting pin Cooperation with jack is fixed on such devices.

And with reference to figure 3, for example, device is a motor 21, ontology is motor body, the current input terminal of the motor 21 211 connect with the terminal output end 222 of bandwidth DC filtering circuit 22, the end that input current passes through bandwidth DC filtering circuit 22 Sub- input terminal 221 is inputted, and output to control motor 21 works after the filtering, to realize that motor 21 controls the filter of signal Wave processing.Certainly, for the ease of the installation of motor 21 and bandwidth DC filtering circuit 22, it is defeated that two can not only be arranged on motor 21 Enter connecting pin, after being connect with bandwidth DC filtering circuit 22 and the circuit board of bandwidth DC filtering circuit 22 being fixed on motor 21 End, circuit board can also be fixed, by the way that fixed structure is arranged in end housing after motor 21 to reduce space hold.

As shown in Fig. 3, Fig. 4 and Fig. 5, the utility model, which provides the bandwidth DC filtering circuit based on shielding case, preferably to be implemented Example

Described device further includes shielding case 23, and the shielding case 23 includes a cavity, the bandwidth DC filtering circuit 22 Setting in the cavity, is provided with multiple through-holes, the terminal input terminal of the bandwidth DC filtering circuit 22 on the shielding case 23 221 and terminal output end 222 extended outside shielding case 23 by corresponding through-hole and the shielding case 23 fitting be arranged in electricity On the shell of machine 21.

Wherein, shielding case 23 is by conducting foam 241 or conducting wire 242 and cage connection, and first, shielding case 23 is by leading Electric foam 241 is bonded on the shell；Second, one end and the shielding case 23 of conducting wire 242 are welded to connect, and the other end is welded with shell Connection.Further, shielding case 23 and the shell of motor 21 are grounded.

As described above, only the best embodiment of the utility model is not intended to limit the scope of the utility model, All equivalent change or modifications made according to the patent scope of the utility model are all that the utility model is covered.

Claims (10)

1. a kind of bandwidth DC filtering circuit based on lead terminal, lead terminal includes terminal input terminal and terminal output end, It is characterized in that：The bandwidth DC filtering circuit includes being arranged between terminal input terminal and terminal output end and setting gradually First order capacitor filtering sub-circuit, second level common mode inductance filtering sub-circuit and third level capacitor filtering sub-circuit.

2. bandwidth DC filtering circuit according to claim 1, it is characterised in that：The second level common mode inductance filtering Circuit includes a MnZn common mode inductance, and the input terminal of the MnZn common mode inductance is connect with terminal input terminal, output end and end Sub- output end connection.

3. bandwidth DC filtering circuit according to claim 2, it is characterised in that：The first order capacitor filtering sub-circuit Including the first BDL capacitances, two electrodes of the first BDL capacitances are connect with the input terminal of common mode inductance respectively, also defeated with terminal Enter end connection, the poles the G ground connection of the first BDL capacitances；And the second level capacitor filtering sub-circuit includes the 2nd BDL electricity Hold, two electrodes of the 2nd BDL capacitances connect with the output end of common mode inductance, also connect with terminal output end respectively, described The poles G of 2nd BDL capacitances are grounded.

4. bandwidth DC filtering circuit according to claim 3, it is characterised in that：It is described include circuit board and shielding case, The shielding case includes a cavity, and circuit board setting is in the cavity and the first BDL capacitances and the 2nd BDL capacitances The poles G connect with shielding case.

5. bandwidth DC filtering circuit according to claim 4, it is characterised in that：The first BDL capacitances and the 2nd BDL The poles G of capacitance are connect in the form of low ESL with shielding case.

6. bandwidth DC filtering circuit according to claim 3, it is characterised in that：The first order capacitor filtering sub-circuit Capacitance >=1uF of 13 the first BDL capacitances, the inductance value of the common mode inductance of second level common mode inductance filtering sub-circuit 14 >= 1mH, appearance value≤100pF of the 2nd BDL capacitances of the third level capacitor filtering sub-circuit 15.

7. a kind of device, it is characterised in that：Described device includes ontology, and power end or control terminal and such as in ontology is arranged Any bandwidth DC filtering circuits of claim 1-6, externally fed power supply pass through bandwidth DC filtering circuit and power supply End connection or external control module are connect by bandwidth DC filtering circuit with control terminal.

8. device according to claim 7, it is characterised in that：Two input of power end or control terminal setting of described device connects Pin, the jack of the output end setting and input connecting pin cooperation of the bandwidth DC filtering circuit, the bandwidth DC filtering The circuit board of circuit is fixed on such devices by inputting the cooperation of connecting pin and jack.

9. device according to claim 8, it is characterised in that：Described device further includes shielding case, and the shielding case includes One cavity, the bandwidth DC filtering circuit setting in the cavity, are provided with multiple through-holes, the bandwidth is straight on the shielding case It flows the input terminal of filter circuit and output end is extended outside shielding case by corresponding through-hole and shielding case fitting setting On the shell of ontology.

10. device according to claim 9, it is characterised in that：The shielding case passes through conducting foam or conducting wire and ontology Cage connection, and be grounded.