CN208862737U - A kind of filter circuit of Switching Power Supply - Google Patents
A kind of filter circuit of Switching Power Supply Download PDFInfo
- Publication number
- CN208862737U CN208862737U CN201821124238.5U CN201821124238U CN208862737U CN 208862737 U CN208862737 U CN 208862737U CN 201821124238 U CN201821124238 U CN 201821124238U CN 208862737 U CN208862737 U CN 208862737U
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- Prior art keywords
- common mode
- circuit
- filter
- capacitance
- power supply
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- 229920000728 polyester Polymers 0.000 claims abstract description 24
- 239000003990 capacitor Substances 0.000 claims description 42
- 238000001914 filtration Methods 0.000 claims description 12
- 230000000694 effects Effects 0.000 abstract description 6
- 230000005611 electricity Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 230000010349 pulsation Effects 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
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Abstract
The utility model discloses a kind of filter circuits of Switching Power Supply, including polyester capacitance, common mode lc circuit, second level RC- π type filter circuit and load resistance；The both ends of polyester capacitance are connect with the input terminal of common mode lc circuit, and polyester capacitance gives common mode lc circuit for output after being filtered externally input voltage signal to be filtered；The output end of common mode lc circuit is connect with the input terminal of second level RC- π type filter circuit；The output end of second level RC- π type filter circuit and the both ends of load resistance connect.The utility model can effectively inhibit ripple, high frequency spikes pulse and low-frequency disturbance, reach good filter effect.
Description
Technical field
The utility model relates to filter circuits, more particularly to suitable for the filter circuit of Switching Power Supply.
Background technique
LED needs special driving power to power for it due to its unique electrical characteristic.LED is generallyd use out at present
Close power drives.The features such as Switching Power Supply is small in size, light-weight and high-efficient due to its, in electronic equipment and electronics and information industry
In be widely used, play the role of in hyundai electronics technical field of electric power very important.Switching Power Supply main composition includes whole
Current circuit, transformer, field-effect tube, compares amplifying circuit, PFM circuit etc. at filter circuit.The output voltage of rectification circuit is not
Pure direct current contains biggish ripple component in waveform.To obtain more satisfactory DC voltage, need to utilize filtered electrical
Road filters out the ripple component in Output Voltage in Rectified Circuits.
Compared with linear power supply, Switching Power Supply performance has the advantages of being difficult analogy, however due to itself power conversion
Mechanism, cause to generate stronger electromagnetic interference noise.Electromagnetic interference noise is broadly divided into DM EMI and common mode interference.It is opening
DM EMI primary fingerprint wave voltage in powered-down source, that is, the surge voltage being mixed in DC voltage, make voltage magnitude occur compared with
Big variation, surge voltage may cause diode breakdown perhaps capacitor burn be easy to make electronic equipment carry out maloperation or
Detection data entanglement.In addition, the rectifier diode in Switching Power Supply has reverse recovery characteristic, in the moment of switch state switching
Reversed peak current can be generated, simultaneously because the influence of circuit distribution parameter and parasitic capacitance, causes resonance to generate a large amount of
Harmonic components interfere, and this noise is referred to as high frequency spikes pulse, and Amplitude Ration ripple is much larger, belong to common-mode noise,
It is very big to the destruction of circuit.
Traditional Switching Power Supply mostly uses electrolytic capacitor to be filtered greatly, and this filtering mode is only to inhibition Ripple Noise effect
Fruit is significant, can not but inhibit high frequency spikes pulse.In addition, the reliability of electrolytic capacitor is low, service life is short, not with the pole LED
Match, it has also become the short slab of LED illumination System；And the presence of electrolytic capacitor will affect driving power miniaturization, it is integrated and
Integral layout；Meanwhile electrolytic capacitor will affect the luminous efficiency and light decay of LED because of output ripple residual caused by oneself factor,
These disadvantages may become more serious in automotive environment (high temperature, narrow space etc.).
Summary of the invention
The technical problem to be solved by the utility model is to provide a kind of filter circuits of Switching Power Supply, can be effective
Ground inhibits ripple, high frequency spikes pulse and low-frequency disturbance, reaches good filter effect.
In order to solve the above technical problems, the utility model embodiment provides a kind of filter circuit of Switching Power Supply, including
Polyester capacitance, common mode lc circuit, second level RC- π type filter circuit and load resistance；The both ends of polyester capacitance and common mode lc circuit
Input terminal connection, polyester capacitance give common mode LC electricity for output after being filtered externally input voltage signal to be filtered
Road；The output end of common mode lc circuit is connect with the input terminal of second level RC- π type filter circuit；Second level RC- π type filter circuit it is defeated
The connection of the both ends of outlet and load resistance.
The utility model at least has following technical effect that
1, it is filtered according to the filter circuit of the utility model embodiment using polyester capacitance, can not only be effectively inhibited
Ripple interference, and can improve Switching Power Supply service life and reliability, while be conducive to the miniaturization, integrated of Switching Power Supply
And integral layout；
2, high-frequency noise is inhibited using common mode lc circuit according to the filter circuit of the utility model embodiment, is used
Second level RC- π type filter circuit in signal remaining ripple and low-frequency disturbance inhibit, and then the straight of stable ideal can be obtained
Galvanic electricity pressure.
Detailed description of the invention
Fig. 1 shows a kind of circuit diagram of one embodiment of the filter circuit of Switching Power Supply of the utility model.
Specific embodiment
The utility model is described in detail in the following with reference to the drawings and specific embodiments.
Fig. 1 shows a kind of circuit diagram of one embodiment of the filter circuit of Switching Power Supply of the utility model.
Please refer to Fig. 1.Filter circuit according to a kind of Switching Power Supply of an embodiment of the present invention includes polyester capacitance C1, common mode LC
Circuit 2, second level RC- π type filter circuit 3 and load resistance RL。
Polyester capacitance C1Both ends connect with the input terminal of common mode lc circuit 2, polyester capacitance C1For by it is externally input to
The voltage signal U of filteringinOutput is to common mode lc circuit 2 after being filtered.The output end and second level RC- π type of common mode lc circuit 2 are filtered
The input terminal of wave circuit 3 connects；The output end and load resistance R of second level RC- π type filter circuit 3LBoth ends connection.
Common mode lc circuit 2 includes common mode inductance L1, the first common mode capacitance C2With the second common mode capacitance C3.Common mode inductance L1's
First input end and the second input terminal are separately connected polyester capacitance C1Both ends, common mode inductance L1The first output end and first total
Mould capacitor C2One end connection, common mode inductance L1Second output terminal and the second common mode capacitance C3One end connection；First common mode electricity
Hold C2The other end and the second common mode capacitance C3The other end be grounded.
Second level RC- π type filter circuit 3 includes the first filter resistance R2, the second filter resistance R3, the first filter capacitor C4,
Two filter capacitor C5With third filter capacitor C6.First filter capacitor C4One end respectively with the first common mode capacitance C2One end and
First filter resistance R2One end connection, the first filter capacitor C4The other end and the second common mode capacitance C3One end connection；Second
Filter capacitor C5One end respectively with the first filter resistance R2The other end and the second filter resistance R3One end connection, second filter
Wave capacitor C5The other end and the first filter capacitor C4The other end connection；Third filter capacitor C6One end respectively with second filter
Wave resistance R3The other end and load resistance RLOne end connection, third filter capacitor C6The other end respectively with the second filtered electrical
Hold C5The other end and load resistance RLThe other end connection.In the present embodiment, load resistance RLFor second level RC- π type filtered electrical
The equivalent resistance of the rear stage circuit on road 3.
Optionally, the first filter capacitor C4, the second filter capacitor C5With third filter capacitor C6It is electrolytic capacitor.
It is preferred that including bleeder resistance R according to the filter circuit of the Switching Power Supply of the utility model embodiment1.It releases
Resistance R1One end respectively with polyester capacitance C1One end and common mode inductance L1First input end connection, bleeder resistance R1It is another
One end respectively with polyester capacitance C1The other end and common mode inductance L1The second input terminal connection.Bleeder resistance R1It can be by polyester electricity
Hold C1The charge discharging resisting of upper accumulation falls, and avoids influencing polyester capacitance C because of charge accumulated1Filtering characteristic.In addition, using common mode
Lc circuit inhibits high-frequency noise, using second level RC- π type filter circuit in signal remaining ripple and low-frequency disturbance into
Row inhibits, and then can obtain the DC voltage of stable ideal.
It in practical applications, can be whole with Switching Power Supply according to the filter circuit of the Switching Power Supply of the utility model embodiment
Current circuit connection.The output voltage of rectification circuit as voltage signal Uin to be filtered, in waveform containing biggish pulsation at
Point.The output voltage signal of rectification circuit passes through the filtering of polyester capacitance C1, can remove most ripple interference, then again
High-frequency impulse interference is removed by common mode lc circuit 2.It, still can remainder in voltage signal after the filtering of common mode lc circuit 2
Original ripple and other low-frequency disturbances.Therefore, it is provided with according to the filter circuit of the Switching Power Supply of the utility model embodiment
Second level RC- π type filter circuit 3, effectively to inhibit remaining ripple and the low-frequency disturbance in signal.
The first filter capacitor C is first passed through by the filtered voltage of common mode lc circuit 24Filtering, a part of low frequency is done
It disturbs and filters out, output voltage at this time is U1；Output voltage U1It is added to by the first filter resistance R2With the second filter capacitor C5It constitutes
In filter circuit, the second filter capacitor C5Capacitive reactance and the first filter resistance R2A bleeder circuit is constituted, U can be further decreased1
In alternating component, reach filtering purpose.For direct current, due to the second filter capacitor C5With blocking effect, so
Second filter capacitor C5With the first filter resistance R2There is no the effect of partial pressure decaying, direct currents to direct current for the bleeder circuit of composition
Pressure passes through the first filter resistance R2After export, constitute output voltage U shown in FIG. 12.Output voltage U2It is then added to by the second filtering
Resistance R3With third filter capacitor C6In the filter circuit of composition, third filter capacitor C6Capacitive reactance and the second filter resistance R3Structure
At a bleeder circuit, make U2In alternating component be further reduced, to obtain best filter effect, therefore, final filter
Wave output voltage UoutVoltage after exactly filtering off ripple interference, high-frequency impulse interference and low-frequency disturbance, pulsation in the voltage at
Divide at least, waveform comparison is smooth.
Polyester capacitance C is used according to the filter circuit of the utility model embodiment1It is filtered, polyester capacitance C1Dielectric
For constant compared with high, small in size, capacity is big, stability is preferable, the indexs such as temperature characterisitic, environmental suitability are better than electrolytic capacitor,
It is very suitable for work in high temperature and narrow space environment, can not only effectively inhibits ripple interference, and can improve
The service life and reliability of Switching Power Supply, while being conducive to the miniaturization of Switching Power Supply, integrated and integral layout.In addition,
High-frequency noise is inhibited using common mode lc circuit 2 according to the filter circuit of the Switching Power Supply of the utility model embodiment, is adopted
With second level RC- π type filter circuit 3 in signal remaining ripple and low-frequency disturbance inhibit, and then stable ideal can be obtained
DC voltage.
Claims (5)
1. a kind of filter circuit of Switching Power Supply, which is characterized in that the filter circuit of the Switching Power Supply include polyester capacitance,
Common mode lc circuit, second level RC- π type filter circuit and load resistance；
The both ends of the polyester capacitance are connect with the input terminal of the common mode lc circuit, and the polyester capacitance is used for external input
Voltage signal to be filtered be filtered after output to the common mode lc circuit；The output end of the common mode lc circuit with it is described
The input terminal of second level RC- π type filter circuit connects；The output end of the second level RC- π type filter circuit and the load resistance
Both ends connection.
2. a kind of filter circuit of Switching Power Supply according to claim 1, which is characterized in that the common mode lc circuit includes
Common mode inductance, the first common mode capacitance and the second common mode capacitance；The first input end of the common mode inductance and the second input terminal difference
The both ends of the polyester capacitance are connected, the first output end of the common mode inductance is connect with one end of first common mode capacitance,
The second output terminal of the common mode inductance is connect with one end of second common mode capacitance；The other end of first common mode capacitance and
The other end of two common mode capacitances is grounded.
3. a kind of filter circuit of Switching Power Supply according to claim 2, which is characterized in that the second level RC- π type filtering
Circuit includes the first filter resistance, the second filter resistance, the first filter capacitor, the second filter capacitor and third filter capacitor；
One end of first filter capacitor respectively with one end of first common mode capacitance and first filter resistance one
End connection, the other end of first filter capacitor are connect with one end of second common mode capacitance；Second filter capacitor
One end connect respectively with one end of the other end of first filter resistance and second filter resistance, it is described second filtering
The other end of capacitor is connect with the other end of first filter capacitor；One end of the third filter capacitor is respectively with described
The other end of two filter resistances is connected with one end of the load resistance, the other end of the third filter capacitor respectively with it is described
The other end of second filter capacitor is connected with the other end of the load resistance.
4. a kind of filter circuit of Switching Power Supply according to claim 3, which is characterized in that the filtering of the Switching Power Supply
Circuit includes bleeder resistance；One end of the bleeder resistance respectively with one end of the polyester capacitance and the common mode inductance
The connection of one input terminal, the other end of the bleeder resistance respectively with the other end of the polyester capacitance and the common mode inductance the
The connection of two input terminals.
5. a kind of filter circuit of Switching Power Supply according to claim 4, which is characterized in that first filtered electrical
Hold, the second filter capacitor and third filter capacitor are electrolytic capacitor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821124238.5U CN208862737U (en) | 2018-07-16 | 2018-07-16 | A kind of filter circuit of Switching Power Supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821124238.5U CN208862737U (en) | 2018-07-16 | 2018-07-16 | A kind of filter circuit of Switching Power Supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208862737U true CN208862737U (en) | 2019-05-14 |
Family
ID=66412745
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201821124238.5U Expired - Fee Related CN208862737U (en) | 2018-07-16 | 2018-07-16 | A kind of filter circuit of Switching Power Supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN208862737U (en) |
-
2018
- 2018-07-16 CN CN201821124238.5U patent/CN208862737U/en not_active Expired - Fee Related
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| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20190514 |