CN201063532Y - Noise suppression circuit of power supply module - Google Patents
Noise suppression circuit of power supply module Download PDFInfo
- Publication number
- CN201063532Y CN201063532Y CNU2007201533865U CN200720153386U CN201063532Y CN 201063532 Y CN201063532 Y CN 201063532Y CN U2007201533865 U CNU2007201533865 U CN U2007201533865U CN 200720153386 U CN200720153386 U CN 200720153386U CN 201063532 Y CN201063532 Y CN 201063532Y
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- power module
- electric capacity
- copper
- lonely
- described power
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Abstract
The utility model discloses a noise suppression circuit of a power supply module which comprises a common mode filtering and differential mode filtering circuit connected with the input end of the power supply module, a common mode filtering and differential mode filtering circuit connected with the output end of the power supply module, connecting capacitors the quantity of which is same as that of input pins and output pins of the power supply module as well as an isolated copper. One end of each connecting capacitor is connected to one input or one output pin of the power supply module, the other end of each connecting capacitor is connected with the isolated copper; the isolated copper is arranged below the power supply module and is connected between the connecting capacitor connected with the input end and the connecting capacitor connected with the output end. The utility model ensures that the noise produced by the power supply module is limited inside or near the power supply module, can not have bigger influence on other parts of the system, thereby greatly decreasing the noise jamming of the power supply module to the external world.
Description
Technical field
The utility model relates to the peripheral filter circuit of noise suppressed of power module on the printed circuit board.
Background technology
A communication product, its supply power mode can be divided into centralized power supply system and distributed power supply mode, the distributed power supply mode mainly relies on the power module (AC-DC or DC-DC power module) of each veneer, will concentrate the single power supply of supplying with to be transformed into the needed multiple power supply of each veneer.Such advantage is that an one-board power supply goes wrong, and can not have influence on the operate as normal of other veneers; Shortcoming is because the introducing of power module, cause system's electromagnetic interference noise bigger than centralized power supply system, especially the power module conduction and the noise of radiation to external world is very strong, causes the EMC of system (Electro Magnetic Compatibility, Electro Magnetic Compatibility) degradation.And the EMC performance of product has also determined product design quality and its inherent reliability.Current various countries are also more and more higher to the EMC performance demands, and product E MC performance directly affects the market access, share and the profit of product.
Want to solve the external coupling noise problem of power module, will set about from the design optimization of the peripheral filter circuit of power module.
Figure 1 shows that the power module filter circuit with noise suppressing function of prior art.
As shown in Figure 1, existing power module filter circuit with noise suppressing function is made up of two parts, a part is made up of the common mode filtering and the differential mode filter circuit of power module input (1,2 pin), and another part is made up of the common mode filtering and the differential mode filter circuit of power module outlet (3,4 pin).
The power module noise suppressed filter circuit of prior art, common-mode noise and differential mode noise that power module is produced have certain inhibitory action, but on the one hand since distributed power supply that the filter circuit of one-board power supply module is laid space requirement is relatively harsher, usually the space is relatively more nervous, the influence that the selection of filtering device is subjected to space layout is bigger, on the other hand, power module is nearer relatively apart from other digital circuits, the common-mode noise of power module is coupled in other adjacent digital circuits easily, especially be coupled in the public zone network, so existing power module filter circuit is often unsatisfactory to the filter effect of common-mode noise, sometimes conduction of power module and radiation common-mode noise can surpass the limit value of regulation, cause very big common-mode noise to disturb.
Summary of the invention
Technical problem to be solved in the utility model is to overcome the deficiencies in the prior art, a kind of power module filter circuit with good noise suppressed effect is provided, thereby solves the external coupled problem of power module self conduction and radiation common-mode noise preferably.
The utility model adopts following technical scheme.
The noise suppression circuit of power module, comprise the common mode filtering and the differential mode filter circuit that are connected with the input of described power module, and the common mode filtering and the differential mode filter circuit that are connected with the output of described power module, also comprise connection electric capacity identical and a lonely copper with the input and output pin number of described power module; Each connects electric capacity one end and is connected to of described power module and inputs or outputs on the pin, and the other end links to each other with described lonely copper, to suppress the common-mode noise from described power module by described pin transmission; Described lonely copper is installed in described power module below, and be connected link to each other with described input be connected electric capacity and with being connected between the electric capacity that described output links to each other, connect line inductance between electric capacity to reduce each.
Preferably, described connection electric capacity is ceramics or the Leaded Ceramic Disc Capacitor that certain voltage withstand class is arranged.
Further, the appearance value of described connection electric capacity selects to depend on the noise frequency value of the described power module that will suppress; When described connection electric capacity is patch capacitor, described appearance value by
Estimate that wherein C is the appearance value of described connection electric capacity, f is the noise frequency value of described power module, and L is the equivalent series inductance value of described connection electric capacity self.
Further, the voltage withstand class of described connection electric capacity is not less than the isolation compressive resistance of described power module.
Further, described lonely copper is installed in described power module below and is positioned at the printed board back side of described power module.
Preferably, the spacing of described lonely copper and bus plane, stratum or other holding wire is greater than 5mm.
Preferably, described lonely copper is rectangle, and consistent with the silk-screen border of described power module encapsulation along the horizontal boundary of described power module input and output direction.
Further, the horizontal boundary length of described lonely copper is less than the distance between described input and the output pin inward flange.
Further, described lonely copper respectively is 1 to 3mm perpendicular to the described pin inward flange that inputs or outputs of the longitudinal boundary of described power module input and output direction distance.
Adopt scheme of the present utility model, guaranteed noise limit that power module produces at power module inner or near, can not produce bigger influence, thereby greatly reduce power module self noise jamming to external world system's other parts.
Description of drawings
Fig. 1 is the power module filter circuit block diagram with noise suppressing function of prior art;
Fig. 2 is the power module filter circuit block diagram of the utility model embodiment;
Fig. 3 is that the input and output of the utility model embodiment connect the electric capacity fundamental diagram.
Embodiment
Below in conjunction with accompanying drawing embodiment of the present utility model is described in further detail.
As shown in Figure 2, the input pin one of power module, 2 connects common mode filtering and differential mode filter circuit, and the output pin 3,4 of power module connects another common mode filtering and differential mode filter circuit; Described input pin one, 2 with output pin 3,4 also respectively be connected capacitor C 1, C2 and C3, C4 links to each other, described connection capacitor C 1, C2, C3 and C4 have suppressed the common-mode noises from described power module transmitted by described pin one, 2,3 and 4; The other end that connects capacitor C 1, C2, C3 and C4 all is connected on the lonely copper that is arranged on the power module below, be described lonely copper be connected link to each other with described input pin one, 2 be connected capacitor C 1, C2 and with being connected between capacitor C 3, the C4 that described output pin 3,4 links to each other, can reduce each and connect line inductance between electric capacity.
Wherein, connecting capacitor C 1, C2, C3 and C4 is the paster ceramic disc capacitor that certain voltage withstand class is arranged.The purpose of selecting ceramic disc capacitor for use is that the high-frequency suppressing effect of ceramic disc capacitor is preferable.The appearance value of described connection capacitor C 1, C2, C3 and C4 selects to depend on the common-mode noise frequency values of the power module that will suppress; The common mode noise signal of the 20MHz-30MHz of general power module is more intense, should be at the suitable capacitance of this Frequency Band Selection.Herein can basis at patch capacitor
The formula estimation connects the capacitance of capacitor C 1, C2, C3 and C4, and wherein f is the noise frequency value of described power module, and L is the equivalent series inductance value of described connection electric capacity self; The capacitance that calculates is not considered pad in the actual printed board, via hole and the influence that connects track, also need determine to connect the appearance value of capacitor C 1, C2, C3 and C4 on the capacitance basis of estimation by test.By calculating and actual test, when choosing 0.01uF, the power supply conducted noise there is the inhibition effect of 10-20DB, the radiated noise that power supply is caused has the inhibition effect of 5-10DB.
The requirement of withstand voltage that connects capacitor C 1, C2, C3 and C4 depends on the isolation requirement of withstand voltage of power module input and output, as long as be not less than the isolation compressive resistance of power module; For communication DC-DC power module commonly used, the withstand voltage selection that connects capacitor C 1, C2, C3 and C4 gets final product greater than 600V, and general selection 1000V withstand voltage is good when reality is used.
When the circuit place and route, should notice that the lonely copper face of power module below amasss under the condition that guarantees power module input and output isolation requirement of withstand voltage big as far as possible.General lonely copper shape is chosen as rectangle, rectangle is imported and output pin inward flange spacing less than described power module along the horizontal boundary length of power module input and output direction, and the longitudinal boundary of the vertical power module input and output of promptly lonely copper direction and the distance that inputs or outputs the pin inward flange of described power module are 1-3mm (requirement of withstand voltage according to the power module input and output is determined); To communication DC-DC power module commonly used, it is good that actual pitch is selected 2mm.Simultaneously, the horizontal boundary of lonely copper is consistent with the silk-screen border of described power module encapsulation.In addition, the spacing of lonely copper and bus plane, stratum or other holding wires is more preferably greater than 5mm.
As shown in Figure 3, the common-mode noise that power module self produces, especially the common-mode noise of power module isolating transformer T generation is the most serious, and this common-mode noise is coupled on the HW highway of place of working by power isolation transformer distributed capacitance C ', and then other digital circuits are exerted an influence.Connect capacitor C by between the power supply input/output terminal, increasing, and select suitable capacitance, the major part of this common-mode noise is limited in power module inside by connecting capacitor C and following lonely copper, the common-mode noise that is coupled to like this on the public ground path significantly reduces, thereby has significantly reduced the external coupling energy of power module conduction and radiation common-mode noise.Here why adopt lonely copper to connect, and lonely copper face is long-pending big as far as possible, rather than adopts printed conductor directly to link to each other, purpose is to reduce the line inductance that connects between the electric capacity as far as possible.
Obviously under the situation that does not break away from spirit and scope of the present utility model, those of ordinary skill in the art can make various modifications and variations to the utility model.Therefore, the utility model covers improvement and the modification within all scopes that fall into claims and equivalent place thereof.
Claims (9)
1. the noise suppression circuit of power module, comprise the common mode filtering and the differential mode filter circuit that are connected with the input of described power module, and the common mode filtering and the differential mode filter circuit that are connected with the output of described power module, it is characterized in that, also comprise connection electric capacity identical and a lonely copper with the input and output pin number of described power module; Each connects electric capacity one end and is connected to of described power module and inputs or outputs on the pin, and the other end links to each other with described lonely copper, to suppress the common-mode noise from described power module by described pin transmission; Described lonely copper is installed in described power module below, and be connected link to each other with described input be connected electric capacity and with being connected between the electric capacity that described output links to each other, connect line inductance between electric capacity to reduce each.
2. noise suppression circuit according to claim 1 is characterized in that, described connection electric capacity is ceramics or Leaded Ceramic Disc Capacitor.
3. noise suppression circuit according to claim 1 and 2 is characterized in that, the appearance value of described connection electric capacity selects to depend on the noise frequency value of the described power module that will suppress; When described connection electric capacity is patch capacitor, described appearance value by
Estimate that wherein C is the appearance value of described connection electric capacity, f is the noise frequency value of described power module, and L is the equivalent series inductance value of described connection electric capacity self.
4. noise suppression circuit according to claim 2 is characterized in that, the voltage withstand class of described connection electric capacity is not less than the isolation compressive resistance of described power module.
5. noise suppression circuit according to claim 1 is characterized in that, described lonely copper is installed in described power module below and is positioned at the printed board back side of described power module.
6. noise suppression circuit according to claim 5 is characterized in that, the spacing of described lonely copper and bus plane, stratum or other holding wire is greater than 5mm.
7. according to claim 1 or 5 or 6 described noise suppression circuits, it is characterized in that described lonely copper is rectangle, and consistent along the horizontal boundary of described power module input and output direction with the silk-screen border of described power module encapsulation.
8. noise suppression circuit according to claim 7 is characterized in that, the horizontal boundary length of described lonely copper is less than the distance between described input and the output pin inward flange.
9. noise suppression circuit according to claim 8 is characterized in that, described lonely copper respectively is 1 to 3mm perpendicular to the described inward flange that inputs or outputs pin of the longitudinal boundary of described power module input and output direction distance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007201533865U CN201063532Y (en) | 2007-06-20 | 2007-06-20 | Noise suppression circuit of power supply module |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007201533865U CN201063532Y (en) | 2007-06-20 | 2007-06-20 | Noise suppression circuit of power supply module |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201063532Y true CN201063532Y (en) | 2008-05-21 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2007201533865U Expired - Lifetime CN201063532Y (en) | 2007-06-20 | 2007-06-20 | Noise suppression circuit of power supply module |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201063532Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105305782A (en) * | 2014-06-09 | 2016-02-03 | 上海紫竹新兴产业技术研究院 | Electromagnetic interference suppression circuit of power MOSFET driver chip |
| CN113114382A (en) * | 2020-01-13 | 2021-07-13 | 华为技术有限公司 | Power supply filtering device |
-
2007
- 2007-06-20 CN CNU2007201533865U patent/CN201063532Y/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105305782A (en) * | 2014-06-09 | 2016-02-03 | 上海紫竹新兴产业技术研究院 | Electromagnetic interference suppression circuit of power MOSFET driver chip |
| CN113114382A (en) * | 2020-01-13 | 2021-07-13 | 华为技术有限公司 | Power supply filtering device |
| CN113114382B (en) * | 2020-01-13 | 2023-09-01 | 华为技术有限公司 | Power supply filtering device |
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| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20080521 |
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| CX01 | Expiry of patent term |