CN2743863Y - Integrated liquid crystal display power device - Google Patents
Integrated liquid crystal display power device Download PDFInfo
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- CN2743863Y CN2743863Y CN 200420095399 CN200420095399U CN2743863Y CN 2743863 Y CN2743863 Y CN 2743863Y CN 200420095399 CN200420095399 CN 200420095399 CN 200420095399 U CN200420095399 U CN 200420095399U CN 2743863 Y CN2743863 Y CN 2743863Y
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- power supply
- circuit
- crystal display
- liquid crystal
- utility
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Abstract
The utility model relates to a power supply device of integrated liquid crystal display equipment, and particularly, the power supply device of integrated liquid crystal display equipment comprises a rectification circuit (1), a cold cathode fluorescent tube driving circuit (3) and a direct current power supply (7) which are respectively connected with the rectification circuit (1). The utility model provides a power supply device of integrated liquid crystal display equipment, which combines the existing switch power supply and a cold cathode fluorescent tube inverter into a whole body. By decreasing electric energy conversion once, the utility model attains the purposes of decreasing energy dissipation and complete machine heating, lowing cost, and simultaneously improving reliability. After the utility model is adopted, the obtainable effects as follows: the utility model can considerably improve the complete machine power utilization efficiency of the liquid crystal display power device, reduce the reliability decrease generated by heating, and the utility model can also reduce the number and the volume of circuit parts, decrease working process, and lower cost.
Description
Technical field
The utility model relates to lcd technology, be particularly related to utilization of power efficient height, volume is little, cost is low combined type cold cathode fluorescent tube Driving technique and power supply provisioning technique, the backlight drive and the power source integral scheme of high performance-price ratio is provided for large-screen liquid crystal display television and LCD.
Technical background
Liquid crystal display generally all is as backlight with cathode fluorescent tube (CCFL).Lighting CCFL needs the alternating voltage of a hundreds of to several kilovolts, and producing the needed voltage of CCFL need realize by an inverter (Inverter).In traditional liquid crystal display, the power supply of complete machine and CCFL drive the circuit arrangement of the general Fig. 2 of employing.The 110-240V civil power changes low-voltage DC supply inverter and other circuit into by Switching Power Supply, and again that power supply is the secondary low-voltage DC of inverter is converted to the needed AC high voltage of CCFL and lights CCFL.
In the scheme of a plurality of independent current source power supplies of prior art, mainly utilize switching mode electricity-magnetic-electric conversion regime to realize voltage transitions, control and safety isolation.Conversion each time all can produce switching loss or the like the energy loss of copper loss, iron loss and the semiconductor devices of transformer.Use water conservancy term metaphor, Switching Power Supply is transformed into the big drop process of low-voltage DC with the high-voltage alternating civil power, because of the problem of conversion efficiency can produce the part energy loss; And inverter can produce the part energy loss with the big lift process that low-voltage direct is converted to High Level AC Voltage.The electrical source consumption of CCFL occupies the major part of complete machine electrical source consumption in large-sized liquid crystal display, and the energy loss that therefore twice conversion caused can be very big; These energy losses also can produce heat, influence the reliability of liquid crystal display.The way of twice conversion simultaneously also can make the circuit complexity, and is with high costs.Also have some to vibrate from the elementary generation of power supply and drive the scheme of CCFI, it is elementary that CCFL is connected on power supply in these schemes, do not come the signal of couple current sampled signal and brilliance control and open and close lamp by optocoupler or magnetic coupler.And CCFL is connected on secondary circuit in the liquid crystal display, and the signal of control brightness and open and close lamp is also secondary at power supply.Because security needs, the primary and secondary part of electronic equipment needs strictly to isolate.Therefore these schemes are mainly used in other occasions such as lamp box.The scheme of a plurality of independent current sources of prior art power supply can't solve that volume is big, circuit is complicated, conversion efficiency is low and the problem of poor reliability.
The problem that prior art exists is that the conversion efficiency of twice switching mode electricity-magnetic-electricity is low, and energy loss is big;
It is unreasonable that the problem that also exists in the prior art is that the CCFL current feedback circuit is provided with, and primary and secondary insulation request is too high.
Summary of the invention
In order to overcome above-mentioned weak point of the prior art, the utility model proposes a kind of integrated form liquid crystal display supply unit, to have Switching Power Supply now and the cathode fluorescent tube inverter unites two into one, by reducing by an electric energy conversion, reach the heating of minimizing energy loss and complete machine, reduce cost, improve the purpose of reliability simultaneously.
The technical scheme that the utility model solves twice low problem of electricity-magnetic-photoelectric transformation efficiency is: the AC generating circuit that and then a high voltage variable high pressure is set behind rectification, filtering circuit is supplied other circuit of the dc power supply circuit feed flow crystal display device of CCFL and a high voltage variable low pressure.
The utility model further solves the technical scheme that the CCFL current feedback circuit is provided with unreasonable problem, adopts the CCFL driver transformer that meets safe insulation request; Secondary CCFL is carried out current sampling, and, be coupled to elementary control CCFL driving circuit, reach the purpose of lamp current being controlled secondary by optocoupler or magnetic coupler with secondary brightness control signal and open and close modulating signal.
The purpose of this utility model can reach like this:
Design, manufacturing a kind of integrated form liquid crystal display supply unit, especially this device comprise rectification circuit and the cathode fluorescent tube driving circuit and the dc power supply that link to each other with described rectification circuit respectively.
A step-up switching power supply converter (Boost Mode DC-DC Converter) can also be set between rectification circuit and cathode fluorescent tube driving circuit that is attached thereto and dc power supply circuit will be converted to a high voltage direct current in order to reach better effect through the Rectified alternating current of overcommutation, this part circuit can play the effect of power-factor improvement (PFC), can reduce the influence of line voltage variation for cathode fluorescent tube driving circuit and dc power supply circuit simultaneously.
A dc power supply circuit also is set, is used for supplying liquid crystal display other parts circuit.Dc power supply also produces and the control section power supply to exchanging simultaneously.Dc power supply from partial circuits such as the shared AC rectification of CCFL drive part, step-up switching power supply converter to reduce cost.
Obtainable effect is after adopting the utility model, and the complete machine power consumption efficiency of liquid crystal display is improved greatly, reduces because the reliability that heating brings reduces; Can reduce the number of spare parts and the volume of circuit, also reduce manufacturing procedure, reduce cost.
Description of drawings
Fig. 1 is the entire block diagram of the utility model integrated form liquid crystal display supply unit;
Fig. 2 is a prior art liquid crystal display multiple conversions power supply power supply synoptic diagram;
Fig. 3 is the rectification and the DC voltage converting circuit schematic diagram of supply unit described in the utility model;
Fig. 4 is circuit theory diagrams such as supply unit vibration described in the utility model, driving and feedback;
Fig. 5 is the dc power supply circuit theory diagrams of supply unit described in the utility model.
EmbodimentBelow in conjunction with accompanying drawing in detail specific embodiment of the utility model is described in detail.
A kind of integrated form liquid crystal display supply unit, especially this device comprises rectification circuit 1, and the cathode fluorescent tube driving circuit 3 and the accessory power supply 7 that link to each other with described rectification circuit 1 respectively.
A step-up switching power supply converter (Boost Mode DC-DC Converter) can be set between described rectification circuit 1 and cathode fluorescent tube driving circuit 3 that is attached thereto and the dc power supply 7, to be converted to high voltage direct current through the Rectified alternating current of overcommutation, this part circuit plays the effect of active power-factor improvement (PFC) simultaneously.
The output of described cathode fluorescent tube driving circuit 3 connects cathode fluorescent tube 6 through safety isolated form driver transformer 4;
One group of output of described dc power supply 7 connects the operating voltage end of described cathode fluorescent tube driving circuit 3.This low power dc power supply circuit that is provided with is used for supplying liquid crystal display other parts circuit.Dc power supply also produces and the control section power supply to exchanging simultaneously.Dc power supply from partial circuits such as the shared AC rectification of CCFL drive part, step-up switching power supply converter to reduce cost.
Described driving circuit 3 also connects light or the sampling feedback control of magnetic coupling type lamp current and brightness and switch lamp control circuit 5.
Described supply unit comprises a housing that holds described rectification circuit 1, dc voltage changer 2, driving circuit 3, driver transformer 4, feedback circuit 5 and accessory power supply 7.
In the practicality, Fig. 3 to Fig. 5 has the two-in-one cold cathode fluorescent tube inverter of the utility model integrated form liquid crystal display supply unit of described feature and the embodiment of power supply.
The 90-240V civil power is added on the rectifier bridge heap D1 through the filter network that is made of T2, C1, C21, C22, C5, and rectification obtains the half-wave pulsating dc voltage that peak value is 127-339V at the L1 left end through D1.U1 is the power-factor improvement IC of a special use, and it and metal-oxide-semiconductor Q1, inductance L 1, peripheral cells such as commutator tube D4, filter capacitor C9 have together constituted a complete active power factor correction circuit.Its ultimate principle adopts a BOOST type DC boosting change-over circuit exactly, converts the low pressure pulsating direct current to stable high relatively dc constant voltage.In the present embodiment, this DC voltage is set at 385V.The potential-divider network that R13, R14, R15 constitute is finished the sampling to output voltage.R11, C8 are the timing resistor and the electric capacity of oscillator, and their value has determined the frequency of operation of power-factor improvement device.R2 is a current sampling resistor, and when the electric current when the Q1 conducting on the L1 was excessive, Q1 can be cut off, and damages because of overcurrent to prevent circuit.
Among Fig. 4, U4 is the pulse-width-modulation driver of both-end output, included that voltage reference, vibration produce, error ratio, functions such as output driving, soft start.It and metal-oxide-semiconductor Q5, Q6 wait common formation semibridge system power driving circuit.Energy is coupled to secondary drive cold cathode fluorescent lamp LAMP1 and LAMP2 by transformer T4.C33, C34 and T4 level constitute harmonic circuit, and making the voltage that drives CCFL is the near sinusoidal ripple.And T4 also has just, inferior utmost point buffer action.U12 and U13 play constant current and constant voltage control respectively, the error signal of voltage and current is fed back to elementary U14 by optocoupler U11, by adjusting dutycycle CCFL is worked under constant electric current, and voltage is unlikely too high and damage circuit and fluorescent tube normally when fluorescent tube open a way.
Fig. 5 is a common AC-DC power circuit, has just omitted rectification, filtering part.It is from the direct power taking of the output of power factor correction circuit 2.Through U15, T5 etc. with power delivery to secondary and change stable 12V and 5V DC voltage, the other parts of supply complete machine into.The 12V DC voltage that 15V that is gone out by the D21 rectification and D20 rectification simultaneously goes out is respectively to primary and secondary part power supplies such as U1, the U4 of this inverter power supply, U11.
Claims (7)
1. integrated form liquid crystal display supply unit is characterized in that:
This device comprises rectification circuit (1), and cathode fluorescent tube driving circuit (3) that links to each other with described rectification circuit (1) respectively and dc power supply (7).
2. supply unit according to claim 1 is characterized in that:
The output of described cathode fluorescent tube driving circuit (3) connects cathode fluorescent tube (6) through safety isolated form driver transformer (4);
One group of output of described dc power supply (7) connects the operating voltage end of described cathode fluorescent tube driving circuit (3).
3. supply unit according to claim 2 is characterized in that:
Described driving circuit (3) also connects coupled mode lamp current sampling feedback control circuit (5).
4. supply unit according to claim 3 is characterized in that:
Described lamp current sampling feedback control circuit (5) is the optocoupler mould assembly.
5. supply unit according to claim 3 is characterized in that:
Described lamp current sampling feedback control circuit (5) is a magnetic coupling type.
6. according to claim 4 or 5 described supply units, it is characterized in that:
Also be connected to booster type dc voltage changer (2) between described rectification circuit (1) and cathode fluorescent tube driving circuit (3) that is attached thereto and the dc power supply (7).
7. supply unit according to claim 4 is characterized in that:
Described supply unit comprises a housing that holds described rectification circuit (1), dc voltage changer (2), driving circuit (3), driver transformer (4), feedback circuit (5) and dc power supply (7).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200420095399 CN2743863Y (en) | 2004-11-13 | 2004-11-13 | Integrated liquid crystal display power device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200420095399 CN2743863Y (en) | 2004-11-13 | 2004-11-13 | Integrated liquid crystal display power device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2743863Y true CN2743863Y (en) | 2005-11-30 |
Family
ID=35633881
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200420095399 Expired - Fee Related CN2743863Y (en) | 2004-11-13 | 2004-11-13 | Integrated liquid crystal display power device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2743863Y (en) |
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2004
- 2004-11-13 CN CN 200420095399 patent/CN2743863Y/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: SHENZHEN CITY FANGJUN TECHNOLOGY CO., LTD. Free format text: FORMER OWNER: FANGXIANG SCIENCE AND TECHNOLOGY CO., SHENZHEN CITY Effective date: 20060106 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20060106 Address after: 518040 Guangdong city of Shenzhen province Futian District Cangsong Tairan six Road North Block Building Room 307 Patentee after: Shenzhen Fang Jun Technology Co., Ltd. Address before: 518100, Shenzhen, Guangdong, Futian District, Che Kung Temple, Tian An City digital technology innovation Plaza B, room 1207 Patentee before: Fangxiang Science and Technology Co., Shenzhen City |
|
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |