CN208284211U - A kind of backlight constant-current circuit - Google Patents
A kind of backlight constant-current circuit Download PDFInfo
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- CN208284211U CN208284211U CN201821009479.5U CN201821009479U CN208284211U CN 208284211 U CN208284211 U CN 208284211U CN 201821009479 U CN201821009479 U CN 201821009479U CN 208284211 U CN208284211 U CN 208284211U
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- circuit
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- buck power
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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Abstract
The utility model provides a kind of backlight constant-current circuit, comprising: EMC circuit；Booster circuit；BUCK power supply circuit, includes input terminal, the first output end and second output terminal, and the second output terminal is connected to the booster circuit and is supplied power for output voltage；And single- stage PFC circuit, it include input terminal and output end, the input terminal is connected to the output end of the EMC circuit, and the output end is connected to the input terminal of both the booster circuit and the BUCK power supply circuit simultaneously；Wherein, the VBL voltage of the single- stage PFC circuit output is supplied to the booster circuit and the BUCK power supply circuit.Backlight constant-current circuit provided by the embodiment of the utility model can solve the big problem of single- stage PFC circuit feeder ear voltage output ripple, while reducing product size, reducing cost.
Description
[technical field]
The utility model is about electronic communication field, more specifically, about a kind of backlight constant-current circuit.
[background technique]
Figure 1A shows for a kind of structure of backlight voltage booster circuit 100 of power in 75W-150W range used in the prior art
It is intended to.As shown in Figure 1A, backlight voltage booster circuit 100 includes EMC (Electro Magnetic Compatibility) circuit
102, single- stage PFC (Power Factor Correction) circuit 104, booster circuit 106, power supply circuit 108 and TV mainboard
110.The backlight voltage booster circuit 100 is single- stage PFC circuit+Boost circuit topological structure, and wherein single- stage PFC circuit 104 has two
A output end exports two-way voltage: VBL voltage and 12V voltage respectively.Booster circuit 106 is connected to single- stage PFC circuit 104, single
Grade pfc circuit 104, which exports VBL voltage to booster circuit 106, exports LED constant current；Power supply circuit 108 is connected to single- stage PFC
Circuit 104, booster circuit 106 and TV mainboard 110, power supply circuit of the 12V voltage that single- stage PFC circuit 104 exports to rear class
108 power supplies, to guarantee the supply voltage of LED section and TV main board.
There are the inherent shortcomings of single- stage PFC circuit for this circuit: the output line for the 12V voltage that single- stage PFC circuit 104 is exported
Wave is very big, it is difficult to meet the power supply ripple requirement of TV mainboard 110.Meanwhile 12V voltage requires very the capacitance of filter capacitor
Height causes the volume of integral product big, at high cost, reduces the cost advantage of single- stage PFC circuit.
Specifically, Figure 1B is the circuit diagram that single- stage PFC circuit directly exports 12V voltage in the prior art.By Figure 1B
It is found that 12V voltage is directly exported by single- stage PFC circuit transformer, the defect of this circuit is that 12V ripple voltage is big, thus right
The capacitor's capacity of capacitor C2 requires especially big.When 12V voltage output 36W, even if capacitor C2 selects the capacitance for arriving 20000uF, 12V
Ripple still has 1V or so, it is difficult to meet the ripple requirement of rear class TV main board power supply voltage.
Therefore, in need that a kind of backlight constant-current circuit that ripple voltage and product size is effectively reduced is provided, it is produced with reducing
Product cost.
[summary of the invention]
In view of this, the present invention provides a kind of backlight constant-current circuits, to solve the above problems.
According to the utility model embodiment, a kind of backlight constant-current circuit is provided, comprising: EMC circuit；Booster circuit；BUCK
Power supply circuit, include input terminal, the first output end and second output terminal, the second output terminal be connected to the booster circuit with
Output voltage supplies power for；And single- stage PFC circuit, it include input terminal and output end, the input terminal is connected to the EMC electricity
The output end on road, the output end are connected to the input terminal of both the booster circuit and the BUCK power supply circuit simultaneously；Its
In, the VBL voltage of the single- stage PFC circuit output is supplied to the booster circuit and the BUCK power supply circuit.
It is defeated to can solve single- stage PFC circuit feeder ear voltage according to backlight constant-current circuit provided by the embodiment of the utility model
The big problem of ripple out, while reducing product size, reducing cost.
Further, the VBL voltage generates constant current output after the booster circuit.
Further, further includes: TV mainboard is connected to the first output end of the BUCK power supply circuit, described in reception
The voltage of BUCK power supply circuit output.
Further, the BUCK power supply circuit by the received VBL voltage be depressured to what the TV mainboard needed
Voltage, then export to the TV mainboard to be powered.
Further, the BUCK power supply circuit uses BUCK control mode.
Further, the received VBL voltage of institute is depressured to the booster circuit needs by the BUCK power supply circuit
Voltage, then export to the booster circuit to be powered.
Further, the BUCK power supply circuit is the Switching Power Supply of high frequency control.
Further, the EMC circuit will be output to the input of the single- stage PFC circuit after input voltage rectifying and wave-filtering
End.
Further, the single- stage PFC circuit is controlled by the integrated PWM chip of circuit of reversed excitation and pfc circuit, and defeated
VBL voltage out containing working frequency ripple wave voltage.
Further, the BUCK power supply circuit reduces the ripple voltage of output voltage.
[Detailed description of the invention]
In order to illustrate the embodiment of the utility model or the technical proposal in the existing technology more clearly, below will be to embodiment
Or attached drawing needed to be used in the description of the prior art is briefly described, it should be apparent that, the accompanying drawings in the following description is only
It is the embodiments of the present invention, for those of ordinary skill in the art, without creative efforts, also
Other attached drawings can be obtained according to the attached drawing of offer.
Figure 1A is a kind of structural schematic diagram of backlight voltage booster circuit used in the prior art.
Figure 1B is the partial circuit schematic diagram that single- stage PFC circuit directly exports 12V voltage in the prior art.
Fig. 2 is the block diagram according to the backlight constant-current circuit of the utility model embodiment.
Fig. 3 is the partial circuit schematic diagram according to the backlight constant-current circuit of the utility model.
[specific embodiment]
The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model
Clearly and completely describe, it is clear that the described embodiments are only a part of the embodiments of the utility model, rather than whole
Embodiment.Based on the embodiments of the present invention, those of ordinary skill in the art are without making creative work
Every other embodiment obtained, fall within the protection scope of the utility model.
A kind of backlight constant-current circuit, including EMC circuit, booster circuit, BUCK power supply circuit are provided according to the utility model
And single- stage PFC circuit.BUCK power supply circuit includes input terminal, the first output end and second output terminal, the second output terminal
The booster circuit is connected to supply power for output voltage.Single- stage PFC circuit includes input terminal and output end, the input terminal
It is connected to the output end of the EMC circuit, the output end is connected to the booster circuit and the BUCK power supply circuit simultaneously
The input terminal of the two.Wherein, the VBL voltage of the single- stage PFC circuit output is supplied to the booster circuit and the BUCK is supplied
Circuit.
According to backlight constant-current circuit provided by the embodiment of the utility model, single- stage PFC circuit 12V feeder ear electricity can solve
The problem for pressing output ripple big, while reducing product size, reducing cost.
Fig. 2 is the block diagram according to the backlight constant-current circuit 200 of the utility model embodiment.In one embodiment, backlight
Constant-current circuit 200 may include EMC circuit 202, single- stage PFC circuit 204, booster circuit 206, BUCK power supply circuit 208.Single-stage
Pfc circuit 204 includes an input terminal and an output end, and BUCK power supply circuit 208 includes an input terminal and two outputs
End.After EMC circuit 202 carries out rectifying and wave-filtering to input voltage, it is then outputted to the input terminal of single- stage PFC circuit 204, EMC electricity
The output end on road 202 is connected to the input terminal of single- stage PFC circuit 204, and the output end of single- stage PFC circuit 204 is connected to liter simultaneously
The input terminal of 208 the two of volt circuit 206 and BUCK power supply circuit.In one embodiment, backlight constant-current circuit 200 can also include
TV mainboard 210.First output end of BUCK power supply circuit 208 is connected to TV mainboard 210, and second output terminal is connected to booster circuit
206 are supplied power for output voltage.
In backlight constant-current circuit 200 shown in Fig. 2, the voltage for inputting power grid is defeated after 202 rectifying and wave-filtering of EMC circuit
The input terminal of single- stage PFC circuit 204 is arrived out, and single- stage PFC circuit 204 is carried out by the integrated PWM chip of circuit of reversed excitation and pfc circuit
Control, and the VBL voltage for containing larger working frequency ripple wave voltage is exported, the VBL voltage is realized after booster circuit 206
Constant current output；Meanwhile VBL voltage is also outputted to BUCK power supply circuit 208.Particularly, this BUCK power supply circuit 208 uses BUCK
The received VBL voltage of institute is first depressured to 206 required voltage of TV mainboard 210 and booster circuit, then exported again by control mode
It is powered to 206 two circuits of TV mainboard 210 and booster circuit.TV mainboard 210 is connected to the of institute's BUCK power supply circuit 208
One output end receives the voltage that BUCK power supply circuit 208 exports.
Due to the Switching Power Supply that BUCK power supply circuit 208 is high frequency control, the requirement to filter capacitor is lower, so circuit
The ripple voltage of 12V voltage can be effectively reduced.In addition, BUCK power supply circuit 208 uses BUCK control mode.
As shown in figure 3, Fig. 3 is the partial circuit schematic diagram according to the backlight constant-current circuit of the utility model.Single- stage PFC electricity
Road only exports VBL voltage all the way, and following stage is separately connected booster circuit 206 and BUCK power supply circuit 208, wherein BUCK power supply electricity
The output of road 208 supplies voltage to TV mainboard 210 and booster circuit 206 is powered, and it is defeated that booster circuit 206 provides backlight constant current
Out.
In the present embodiment, original single- stage PFC circuit is substituted using a BUCK power supply circuit 208 and directly exports 12V
The ripple voltage of 12V voltage can be effectively reduced in voltage, meanwhile, after the new departure proposed using the utility model, effectively
Product size is reduced, is reduced costs, when the 12V potential electrolysis capacitance in the presence of the prior art increases, occupies pcb board face
The problem of product also increases effectively is solved.
It should also be noted that, herein, relational terms such as first and second and the like are used merely to one
Entity is distinguished with another entity, and without necessarily requiring or implying between these entities, there are any this actual passes
System or sequence.Moreover, the terms "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, from
And make the article for including a series of elements or equipment not only includes those elements, but also its including being not explicitly listed
His element, or further include for this article or the intrinsic element of equipment.In the absence of more restrictions, by language
The element that sentence "including a ..." limits, it is not excluded that there is also other in the article or equipment for including the element
Identical element.
The foregoing description of the disclosed embodiments can be realized professional and technical personnel in the field or using originally practical new
Type.Various modifications to these embodiments will be readily apparent to those skilled in the art, and determine herein
The General Principle of justice can be realized in other embodiments without departing from the spirit or scope of the present utility model.Cause
This, the present invention will not be limited to the embodiments shown herein, and is to fit to and principles disclosed herein
The widest scope consistent with features of novelty.
Claims (10)
1. a kind of backlight constant-current circuit characterized by comprising
EMC circuit；
Booster circuit；
BUCK power supply circuit, includes input terminal, the first output end and second output terminal, and the second output terminal is connected to the liter
Volt circuit is supplied power for output voltage；And
Single- stage PFC circuit includes input terminal and output end, and the input terminal is connected to the output end of the EMC circuit, described defeated
Outlet is connected to the input terminal of both the booster circuit and the BUCK power supply circuit simultaneously；
Wherein, the VBL voltage of the single- stage PFC circuit output is supplied to the booster circuit and the BUCK power supply circuit.
2. backlight constant-current circuit according to claim 1, which is characterized in that the VBL voltage passes through the booster circuit
After generate constant current output.
3. backlight constant-current circuit according to claim 1, which is characterized in that further include:
TV mainboard is connected to the first output end of the BUCK power supply circuit, receives the voltage of the BUCK power supply circuit output.
4. backlight constant-current circuit according to claim 3, which is characterized in that the BUCK power supply circuit is by a received institute of institute
It states VBL voltage and is depressured to the TV mainboard required voltage, then export to the TV mainboard to be powered.
5. backlight constant-current circuit according to claim 1, which is characterized in that the BUCK power supply circuit is controlled using BUCK
Mode.
6. backlight constant-current circuit according to claim 1, which is characterized in that the BUCK power supply circuit is by a received institute of institute
It states VBL voltage and is depressured to the booster circuit required voltage, then export to the booster circuit to be powered.
7. backlight constant-current circuit according to claim 1, which is characterized in that the BUCK power supply circuit is high frequency control
Switching Power Supply.
8. backlight constant-current circuit according to claim 1, which is characterized in that input voltage is rectified and filtered by the EMC circuit
The input terminal of the single- stage PFC circuit is output to after wave.
9. backlight constant-current circuit according to claim 1, which is characterized in that the single- stage PFC circuit by circuit of reversed excitation and
The integrated PWM chip of pfc circuit is controlled, and exports the VBL voltage containing working frequency ripple wave voltage.
10. backlight constant-current circuit according to claim 9, which is characterized in that the BUCK power supply circuit reduces output electricity
The ripple voltage of pressure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821009479.5U CN208284211U (en) | 2018-06-27 | 2018-06-27 | A kind of backlight constant-current circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821009479.5U CN208284211U (en) | 2018-06-27 | 2018-06-27 | A kind of backlight constant-current circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208284211U true CN208284211U (en) | 2018-12-25 |
Family
ID=64704817
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201821009479.5U Active CN208284211U (en) | 2018-06-27 | 2018-06-27 | A kind of backlight constant-current circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN208284211U (en) |
-
2018
- 2018-06-27 CN CN201821009479.5U patent/CN208284211U/en active Active
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20190509 Address after: 510663 310, 3rd floor, 192 Kezhu Road, Guangzhou High-tech Industrial Development Zone, Guangdong Province (office use only) Patentee after: Guangzhou Kun Electronic Technology Co. Ltd. Address before: 510530 No. 6, Yun Po four road, Whampoa District, Guangzhou, Guangdong. Patentee before: Guangzhou CVT Electronics Technology Co., Ltd. |