CN108231014A - A kind of local dimming constant-current control circuit, driving power and television set - Google Patents
A kind of local dimming constant-current control circuit, driving power and television set Download PDFInfo
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- CN108231014A CN108231014A CN201810126819.0A CN201810126819A CN108231014A CN 108231014 A CN108231014 A CN 108231014A CN 201810126819 A CN201810126819 A CN 201810126819A CN 108231014 A CN108231014 A CN 108231014A
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/10—Controlling the intensity of the light
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- Computer Hardware Design (AREA)
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- Theoretical Computer Science (AREA)
- Circuit Arrangement For Electric Light Sources In General (AREA)
- Discharge-Lamp Control Circuits And Pulse- Feed Circuits (AREA)
Abstract
The invention discloses a kind of local dimming constant-current control circuit, driving power and television sets, wherein, the local dimming constant-current control circuit is connect with AC DC conversion circuits, mainboard and backlight lamp bar, the constant-current driven module including dimming controlling module and built-in boost control circuit and multichannel dimmer switch pipe；The drive signal of mainboard output is received by dimming controlling module and dim signal and is transmitted to constant-current driven module, the constant-current driven module is exported after the first voltage that AC DC conversion circuits export is boosted to predeterminated voltage according to the drive signal to backlight lamp bar, and the grid duty ratio of corresponding channel dimmer switch pipe is adjusted according to the dim signal, and then adjust the size of current of corresponding channel.By using built-in boost control circuit and the constant-current driven module of dimmer switch pipe, the framework of local dimming light source is effectively optimized, the problem of earth loop crosstalk causes electric current unstable is reduced, while effectively reduce pcb board area, achievees the purpose that reduce cost.
Description
Technical field
The present invention relates to appliances power source technical field, more particularly to a kind of control circuit for reducing output voltage ripple is driven
Dynamic power supply and television set.
Background technology
With making rapid progress for science and technology, the development of TV is also to advance by leaps and bounds, and consumer wants picture quality of television
It is also increasingly harsher to ask, and to meet consumer demand, TV producer is also the breakthrough in terms of continuous acquisition of technology.Tool at present
There is the TV of HDR functions, in terms of colour gamut, contrast, depth of field degree, can give visually to bring and strong shake sense, consumer
It is profuse in praise.For LED television, perfect HDR functions, backlight subarea (the i.e. Localdimming functions of module are realized）Then
It performs meritorious deeds never to be obliterated, the backlight subarea design of module can play the role of making something perfect even more perfect.
There is IW7025, IW7027, IW7038 of IWATT producers etc. using more local dimming chip currently on the market.
As shown in Figure 1, alternating current exports 24V or 48V after AC-DC module circuit conversion, Boost liters are carried out to DC-DC module circuit
Pressure powers the voltage after boosting to backlight lamp bar.MCU controls current constant control chip I W7027 by spi bus, by IW7027
Output signal controls switch MOSFETQ1 ~ Q16 of backlight LED light negative terminal, turns it on or closes, while passes through FB foot control systems
DC-DC booster circuit makes it be met the requirements to backlight lamp bar supply voltage.
Further as shown in Fig. 2, IW7027 with IW7038 integral frames are similar, IW7038 is by the switch of backlight lamp bar negative terminal
MOSFET pipes are integrated into chip interior, and for workflow then as IW7027, both frameworks are all using relatively independent
DC turns DC booster circuits, in practical applications, because power is larger, the earth loop and IW7027/7038 of DC-DC booster circuit
Line loop has crosstalk, causes backlight LED light electric current unstable, and screen is led to problems such as to have screen flash or water ripples interference.
Thus the prior art could be improved and improve.
Invention content
Part in view of above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide a kind of local dimming current constant control electricity
Road, driving power and television set, it is effectively excellent by using built-in boost control circuit and the constant-current driven module of dimmer switch pipe
Change the framework of local dimming light source, reduce the problem of earth loop crosstalk causes electric current unstable, while effectively reduce pcb board
Area achievees the purpose that reduce cost.
In order to achieve the above object, this invention takes following technical schemes：
A kind of local dimming constant-current control circuit, connect with AC-DC conversion circuits, mainboard and backlight lamp bar, including light modulation
The constant-current driven module of control module and built-in boost control circuit and multichannel dimmer switch pipe；It is connect by dimming controlling module
The drive signal and dim signal of receipts mainboard output are simultaneously transmitted to constant-current driven module, and the constant-current driven module is according to the drive
Dynamic signal is exported to backlight lamp bar, and after the first voltage that AC-DC conversion circuits export is boosted to predeterminated voltage according to described
Dim signal adjusts the grid duty ratio of corresponding channel dimmer switch pipe, and then adjusts the size of current of corresponding channel.
In the local dimming constant-current control circuit, the constant-current driven module includes boosting unit and built-in boosting control
The constant-current control unit of circuit and multichannel dimmer switch pipe processed；It is exported by the constant-current control unit according to the drive signal
Driving pulse drives the boosting unit to start to work to boosting unit；The boosting unit exports AC-DC conversion circuits
First voltage is exported after boosting to predeterminated voltage to backlight lamp bar；The constant-current control unit is adjusted also according to the dim signal
The grid duty ratio of corresponding channel dimmer switch pipe, and then adjust the size of current of corresponding channel.
In the local dimming constant-current control circuit, the constant-current control unit is also according to the real work of backlight lamp bar
Voltage generation detection voltage, whether the real work voltage that current backlight lamp bar is judged according to the detection voltage is default electricity
Pressure, and according to the duty ratio of the judging result adjusting driving pulse.
In the local dimming constant-current control circuit, the dimming controlling module includes dimming control unit and data pass
Defeated unit, the drive signal and dim signal of mainboard output are received by the dimming control unit, and pass through the data transmission
Unit exports the drive signal and dim signal to constant-current driven module.
In the local dimming constant-current control circuit, the constant-current control unit includes current constant control chip, the perseverance
1st foot of flow control chip connects the boosting unit, and the 5th foot, the 6th foot and the 7th foot of the current constant control chip are all connected with
The dimming controlling module, the 14th foot to the 20th foot of the current constant control chip are all connected with backlight lamp bar.
In the local dimming constant-current control circuit, the boosting unit include inductance, first resistor, second resistance,
3rd resistor, the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, the 9th resistance, the tenth resistance, first
Capacitance, the second capacitance, third capacitance, the 4th capacitance, the first diode, the second diode, the first zener diode, the second voltage stabilizing
Diode and metal-oxide-semiconductor；
The first voltage output terminal of one end connection AC-DC conversion circuits of the inductance, the other end connection second of the inductance
The drain electrode of the anode, metal-oxide-semiconductor of diode and one end of the 8th resistance；The cathode of second diode connects the one of the second capacitance
End, the anode and backlight lamp bar of the anode of third capacitance, the 4th capacitance；The cathode of the third capacitance and the cathode of the 4th capacitance
It is grounded；The other end of second capacitance connects the other end of the 8th resistance and one end of the 9th resistance；Described 9th
The other end of resistance connects one end of the 8th resistance and one end of the first capacitance；The other end connection second of first capacitance is steady
Press one end, one end of the 7th resistance and the source electrode of metal-oxide-semiconductor of the cathode of diode, one end of the 5th resistance, the 6th resistance；It is described
The anode of second zener diode, the other end of the 5th resistance, the other end of the 6th resistance and the other end of the 7th resistance connect
Ground；The metal-oxide-semiconductor grid connection the cathode of the first zener diode, the anode of the first diode, second resistance one end and
One end of 3rd resistor；One end of anode the 5th resistance of connection of first zener diode, the volume other end of 3rd resistor
With one end of the 4th resistance；One end of the cathode connection first resistor of first diode；The other end of the first resistor
Connect the other end of second resistance and one end of the tenth resistance；The other end of 4th resistance connects the current constant control chip
The 22nd foot；The other end of tenth resistance connects the 1st foot of the current constant control chip.
In the local dimming constant-current control circuit, the dimming control unit includes microcontroller, the microcontroller
The 7th foot, the 12nd foot and the 15th foot of device are connect with mainboard, and the 2nd foot, the 3rd foot and the 19th foot of the microcontroller are all connected with institute
State constant-current driven module.
In the local dimming constant-current control circuit, the data transmission unit includes the 11st resistance and the 12nd electricity
Resistance；2nd foot of one end connection microcontroller of the 11st resistance, the other end of the 11st resistance connect the constant current
Drive module；3rd foot of one end connection microcontroller of the 12nd resistance, the other end connection institute of the 12nd resistance
State constant-current driven module.
A kind of driving power including shell, is provided with pcb board in the shell, be provided on the pcb board as described above
Local dimming constant-current control circuit.
A kind of television set, including driving power as described above.
Compared to the prior art, in local dimming constant-current control circuit provided by the invention, driving power and television set, institute
Local dimming constant-current control circuit is stated to connect with AC-DC conversion circuits, mainboard and backlight lamp bar, including dimming controlling module with
And the constant-current driven module of built-in boost control circuit and multichannel dimmer switch pipe；Mainboard output is received by dimming controlling module
Drive signal and dim signal and be transmitted to constant-current driven module, the constant-current driven module will according to the drive signal
The first voltage of AC-DC conversion circuits output is exported to backlight lamp bar, and after boosting to predeterminated voltage according to the dim signal
The grid duty ratio of corresponding channel dimmer switch pipe is adjusted, and then adjusts the size of current of corresponding channel.By using built-in liter
The constant-current driven module of control circuit and dimmer switch pipe is pressed, effectively optimizes the framework of local dimming light source, ground wire is reduced and returns
The problem of road crosstalk causes electric current unstable, while pcb board area is effectively reduced, achieve the purpose that reduce cost.
Description of the drawings
Fig. 1 is the power supply structure block diagram of IW7027 chips in the prior art；
Fig. 2 is the power supply structure block diagram of IW7028 chips in the prior art；
Fig. 3 is the structure diagram of local dimming constant-current control circuit provided by the invention；
Fig. 4 is the circuit diagram of local dimming constant-current control circuit provided by the invention.
Specific embodiment
The present invention provides a kind of local dimming constant-current control circuit, driving power and television set, by using built-in boosting
The constant-current driven module of control circuit and dimmer switch pipe effectively optimizes the framework of local dimming light source, reduces earth loop
The problem of crosstalk causes electric current unstable, while pcb board area is effectively reduced, achieve the purpose that reduce cost.
To make the purpose of the present invention, technical solution and effect clearer, clear and definite, develop simultaneously embodiment pair referring to the drawings
The present invention is further described.It should be appreciated that specific embodiment described herein is not used to only to explain the present invention
Limit the present invention.
Referring to Fig. 3, local dimming constant-current control circuit 10 provided by the invention and AC-DC conversion circuits 20, mainboard 30
Connected with backlight lamp bar 40, input AC electricity exported respectively after AC-DC conversion circuits 20 are converted to direct current first voltage and
Second voltage is to local dimming constant-current control circuit 10 and mainboard 30, and for the two power supply, mainboard 30 exports control signal after working
To the local dimming constant-current control circuit 10, provided accordingly for backlight lamp bar 40 by the local dimming constant-current control circuit 10
Operating voltage, and according to control signal adjustment corresponding channel lamp bar size of current, realize local dimming.Specifically, it is described
Local dimming constant-current control circuit 10 includes dimming controlling module 11 and built-in boost control circuit and multichannel dimmer switch
The constant-current driven module 12 of pipe is received drive signal and dim signal that mainboard 30 exports by the dimming controlling module 11 and is passed
Constant-current driven module 12 is transported to, what the constant-current driven module 12 exported AC-DC conversion circuits 20 according to the drive signal
Output is to backlight lamp bar 40 after first voltage boosts to predeterminated voltage, and adjusts corresponding channel light modulation according to the dim signal and open
The grid duty ratio of pipe is closed, and then adjusts the size of current of corresponding channel.When needing explanatorily, the AC-DC conversion circuits 20 are
The prior art is not herein described further its connection relation.
In the present invention, as a result of built-in boost control circuit and the constant-current driven module of multichannel dimmer switch pipe
12, therefore the local dimming constant-current control circuit 10 is only made of two circuit modules, i.e. constant-current driven module 12 and light modulation
Control module 11, built-in boost control circuit so that earth loop is more succinct, can effectively reduce screen caused by ground wire crosstalk
Curtain has the problems such as screen flash or water ripples are interfered, and effectively optimizes the framework of local dimming light source, and also may be used when pcb board connects up
Area is effectively reduced, reduces the design and debugging difficulty of production cost and local dimming power supply.
Specifically, also referring to Fig. 4, the dimming controlling module 11 includes dimming control unit 111 and data transmission
Unit 112, the dimming control unit 111 connects mainboard 30 and data transmission unit 112, the data transmission unit 112 connect
Connect the constant-current driven module 12；In the present embodiment, the drive signal that mainboard 30 exports is received by the dimming control unit 111
And dim signal, and the I2C data transmissions between constant-current driven module 12 are realized by the data transmission unit 112, it will
The drive signal and dim signal are exported to constant-current driven module 12, it is ensured that digital controlled signal stablizes transmission, provides perseverance
The reliability of flow control.
Further, the constant-current driven module 12 includes boosting unit 121 and built-in boost control circuit and multichannel
The constant-current control unit 122 of dimmer switch pipe, the boosting unit 121 connect the constant-current control unit 122 and backlight lamp bar
40, the constant-current control unit 122 is also connected with the dimming controlling module 11；When driving the work of backlight lamp bar 40, by the perseverance
Flow control unit 122 drives the boosting unit 121 to open according to the drive signal output driving pulse to boosting unit 121
Beginning work；Output is extremely carried on the back after the first voltage that AC-DC conversion circuits 20 export is boosted to predeterminated voltage by the boosting unit 121
Light lamp bar 40；The grid that the constant-current control unit 122 adjusts corresponding channel dimmer switch pipe also according to the dim signal accounts for
Empty ratio, and then adjust the size of current of corresponding channel.In local dimming constant-current control circuit 10 i.e. provided by the invention, it will boost
Control circuit and multichannel dimmer switch pipe are built in constant-current control unit 122, and cooperation boosting unit 121 realizes Boost liters
Pressure, the first voltage that AC-DC conversion circuits 20 are exported are exported after saving compacting predeterminated voltage to backlight lamp bar 40, realize backlight
The normal work of item 40.
Preferably, to ensure the steady operation of backlight lamp bar 40, the constant-current control unit 122 is also according to backlight lamp bar 40
Real work voltage generation detection voltage, according to it is described detection voltage judge that the real work voltage of current backlight lamp bar 40 is
No is predeterminated voltage, and the duty ratio of the driving pulse is adjusted according to judging result.I.e. described constant-current control unit 122 can root
The operating voltage fed back according to backlight lamp bar 40 judges whether current operating voltage meets lamp bar specification, and voluntarily adjustment exports extremely
The voltage of backlight lamp bar 40, specifically, when boosting unit 121 is exported to the overtension of backlight lamp bar 40, i.e. current backlight
When the real work voltage of lamp bar 40 is more than predeterminated voltage, then reduce the duty ratio of driving pulse so that the output of boost voltage
Voltage reduces, until exporting predeterminated voltage to backlight lamp bar 40, and when boosting unit 121 is exported to the voltage mistake of backlight lamp bar 40
When low, i.e., when the real work voltage of current backlight lamp bar 40 is less than predeterminated voltage, then increase the duty ratio of driving pulse so that
The output voltage raising of boost voltage, until exporting predeterminated voltage backlight lamp bar 40, guarantee backlight lamp bar 40 is stablized, the work of safety
Make, improve the stability and reliability of driving power.
Specifically, please continue to refer to Fig. 4, the constant-current control unit 122 includes current constant control chip U1, the constant current
The 1st foot of chip U1 is controlled to connect the boosting unit 121, for controlling the working condition of the boosting unit 121, the perseverance
The 5th foot, the 6th foot and the 7th foot of flow control chip U1 is all connected with the dimming controlling module 11, is used to implement and brightness adjustment control mould
Data communication connection between block 11, the 14th foot to the 20th foot of the current constant control chip U1 are all connected with backlight lamp bar 40,
For 40 negative terminal input terminal of backlight lamp bar, in the present embodiment, the current constant control chip U1 using concave-convex producer model OZ556
Constant-current driven chip, be internally integrated DC-DC boosting rectifier controls end line and multichannel dimmer switch pipe, can realize it is permanent
Simplify power supply structure while flow control, reduce earth loop crosstalk, certainly in other embodiments, other, which can also be used, has
The current constant control chip U1 of identical function, this is not limited by the present invention.
Further, the boosting unit 121 includes fuse F1, inductance L1, first resistor R1, second resistance R2, the
Three resistance R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9,
Ten resistance R10, the first capacitance C1, the second capacitance C2, third capacitance C3, the 4th capacitance C4, the first diode D1, the second diode
D2, the first zener diode ZD1, the second zener diode ZD2 and metal-oxide-semiconductor Q18.
One end of the inductance L1 is described by the first voltage output terminals of fuse F1 connection AC-DC conversion circuits 20
The other end connection drain electrode of anode, metal-oxide-semiconductor Q18 of the second diode D2 of inductance L1 and one end of the 8th resistance R8；Described
Two diode D2 cathode connection one end of the second capacitance C2, the anode of third capacitance C3, the 4th capacitance C4 anode and backlight
Lamp bar 40；The cathode of the third capacitance C3 and the cathode of the 4th capacitance C4 are grounded；The other end of the second capacitance C2 connects
Connect the other end of the 8th resistance R8 and one end of the 9th resistance R9；The other end of the 9th resistance R9 connects the 8th resistance
One end of R8 and one end of the first capacitance C1；The cathode of the second zener diode ZD2 of other end connection of the first capacitance C1,
One end of 5th resistance R5, one end, one end of the 7th resistance R7 and the source electrode of metal-oxide-semiconductor Q18 of the 6th resistance R6；Described second is steady
The other end for pressing the anode of diode ZD2, the other end of the 5th resistance R5, the other end of the 6th resistance R6 and the 7th resistance R7 is equal
Ground connection；The grid of the metal-oxide-semiconductor Q18 connects the cathode of the first zener diode ZD1, the anode of the first diode D1, the second electricity
Hinder one end of R2 and one end of 3rd resistor R3；One end of the 5th resistance R5 of anode connection of the first zener diode ZD1,
The volume other end of 3rd resistor R3 and one end of the 4th resistance R4；The cathode connection first resistor R1's of the first diode D1
One end；The other end of other end connection second resistance R2 of the first resistor R1 and one end of the tenth resistance R10；Described 4th
The other end of resistance R4 connects the 22nd foot of the current constant control chip U1；Described in the other end connection of the tenth resistance R10
The 1st foot of current constant control chip U1.After mainboard 30 works, current constant control chip U1 is according to the drive signal output driving received
Pulse DRV is to the metal-oxide-semiconductor Q18 of boosting unit 121, and boosting unit 121 starts to work, and inductance L1 starts charge and discharge, and energy is through
By the first voltage of AC-DC conversion voltage outputs after two diode D2 and the 4th capacitance C4 rectifying and wave-filterings（It is in the present embodiment
48V）Boost to predeterminated voltage（It is 80V in the present embodiment）, powered by lamp bar socket CN1 to backlight lamp bar 40, after through lamp
Negative terminal is returned inside current constant control chip U1.
Further, the dimming control unit 111 includes microcontroller U2, the 7th foot of the microcontroller U2, the 12nd
Foot and the 15th foot are connect with mainboard 30, described for receiving the control signal such as ON/OFF, ENA, SCK, CSB of the output of mainboard 30
The 2nd foot, the 3rd foot and the 19th foot of microcontroller U2 is all connected with the constant-current driven module 12, is used to implement and drives mould with constant current
I2C data transmissions between block 12 ensure the stability of signal transmission.In the present embodiment, the microcontroller U2 uses model
For the MCU of MSP430G2433IPW20R, certainly in other embodiments, other microcontrollers with identical function can also be used
Device U2, this is not limited by the present invention.
Further, the data transmission unit 112 includes the 11st resistance R11 and the 12nd resistance R12；Described
The 2nd foot of one end connection microcontroller U2 of 11 resistance R11, the other end of the 11st resistance R11 connect the constant current
Drive module 12 specifically connects the 6th foot of the current constant control chip U1；One end connection micro-control of the 12nd resistance R12
The 3rd foot of device U2 processed, the other end of the 12nd resistance R12 connect the constant-current driven module 12, specifically connect the perseverance
The 7th foot of flow control chip U1；The 11st resistance R11 and the 12nd resistance R12 constitutes I2C data transmission circuits, real
Now the spi bus with current constant control chip U1 communicates.
Preferably, to advanced optimize the performance of local dimming constant-current control circuit 10, the constant-current driven module 12 is also
Including the 13rd resistance R13, the 14th resistance R14, the 15th resistance R15, the 16th resistance R16, the 17th resistance R17,
18 resistance R18, the 19th resistance R19, the 20th resistance R20, the 21st resistance R21, the 22nd resistance R22, second
13 resistance R23, the 24th resistance R24, the 25th resistance R25, the 5th capacitance C5, the 6th capacitance C6, the 7th capacitance C7,
8th capacitance C8, the 9th capacitance C9, the tenth capacitance C10 and the 11st capacitance C11.
One end of the 13rd resistance R13 connects the cathode of the second diode D2, and the 13rd resistance R13's is another
One end of the 14th resistance R14 of end connection and the 20th foot of current constant control chip U1 and one end of the 5th capacitance C5, the described tenth
The other end of four resistance R14 is grounded by the 15th resistance R15；The other end ground connection of the 5th capacitance C5；Described 16th
One end connection ENA signal ends of resistance R16, one end of the 17th resistance R17 of other end connection of the 16th resistance R16,
One end of 6th capacitance C6 and the 3rd foot of current constant control chip U1；The other end and the 6th capacitance C6 of the 17th resistance R17
The other end be grounded；One end connection 12V feeder ears, one end of the 8th capacitance C8 and the current constant control core of the 7th capacitance C7
The 4th foot of piece U1, the other end of the 7th capacitance C7 and the other end of the 8th capacitance C8 are grounded；18th resistance
The 5th foot of one end connection current constant control chip U1 of R18, the other end connection microcontroller U2's of the 18th resistance R18
19th foot；One end of the 20th resistance of one end connection of 19th resistance and the 8th foot of current constant control chip U1, the described 19th
The 13rd foot of the other end connection microcontroller U2 of resistance R19；The other end connection 3.3V feeder ears of the 20th resistance R20
With the 9th foot of current constant control chip U1；The 10th foot of one end connection current constant control chip U1 of the 21st resistance R21；
The 11st foot of one end connection current constant control chip U1 of the 22nd resistance R22；One end of the 23rd resistance R23
The 12nd foot of current constant control chip U1 is connected, the other end of the 23rd resistance R23 is grounded by the 9th capacitance C9；It is described
One end of 24th resistance R24 and one end of the 25th resistance R25 are all connected with the 13rd foot of current constant control chip U1；It is described
The 22nd foot of one end connection current constant control chip U1 of tenth capacitance C10；One end connection constant current control of the 11st capacitance C11
The 2nd foot of coremaking piece U1, the other end of the 21st resistance R21, the other end of the 22nd resistance R22, the 24th
The other end of resistance R24, the other end of the 25th resistance R25, the other end of the tenth capacitance C10 and the 11st capacitance C11
The other end is grounded；.
Wherein, the 13rd resistance R13, the 14th resistance R14, the 15th resistance R15 and the 5th capacitance C5 are overvoltage protection
Circuit provides overvoltage protection for backlight lamp bar 40 and improves circuit job security；16th resistance R16, the 17th resistance R17 and
6th capacitance C6 is backlight switch circuit, receives ENA enable signals and is started to work with driving chip, realizes opening for backlight lamp bar 40
It opens and closes；7th capacitance C7 and the 8th capacitance C8 is power supply filter circuit, the first voltage exported to AC-DC conversion circuits 20
For chip power supply after being filtered, filtering clutter ensures the stability of chip power supply；The 18th resistance R18 is mainly used for
The input of synchronizing signal；The 19th resistance R19 and the 20th resistance R20 is mainly used for judging identification input；Described second
11 resistance R21 and the 22nd resistance R22 are mainly used for setting the working frequency of chip；The 23rd resistance R23 and
9th capacitance C9 is mainly used for loop compensation, to realize that voltage is adjusted and feedback protection acts on；The 24th resistance R24
It is mainly used for setting lamp bar electric current with the 25th resistance R25, to realize that light modulation acts on；The 11st capacitance C11 is used for
Current constant control chip U1 provides reference voltage, and the tenth capacitance C10 is mainly used for over-current detection, ensures driving current in safety
In the range of, improve circuit safety.
Further, the dimming controlling module 11 further includes the 26th resistance R26, the 27th resistance R27, second
18 resistance R28, the 29th resistance R29, the 30th resistance R30, the 12nd capacitance C12, the 13rd capacitance C13, the 14th
Capacitance C14, the 15th capacitance C15, Light-emitting diode LED 1 and burn-in receptacle CN2；One end of the 26th resistance R26 connects
3.3V feeder ears are connect, the other end of the 26th resistance R26 connects one end of the 12nd capacitance C12, the 13rd capacitance C13
One end, one end of the 14th capacitance C14 and the 1st foot of microcontroller U2；The other end of the 12nd capacitance C12, the tenth
The other end of three capacitance C13 and the other end of the 14th capacitance C14 are grounded；One end connection of the 27th resistance R27
The 4th foot of burn-in receptacle CN2, the other end of the 27th resistance R27 connect one end and the 3.3V of the 28th resistance R28
Feeder ear；The 2nd foot of the other end connection burn-in receptacle CN2 of the 28th resistance R28 and the one of the 29th resistance R29
End；The 16th foot of other end connection microcontroller U2 of the 29th resistance R29 and one end of the 15th capacitance C15；Institute
State the 3rd foot of one end connection burn-in receptacle CN2 of the 30th resistance R30, the other end connection micro-control of the 30th resistance R30
The 17th foot of device U2 processed；The 1st foot ground connection of the burn-in receptacle CN2；The anode connection microcontroller of the Light-emitting diode LED 1
The 10th foot of device U2, the cathode ground connection of the Light-emitting diode LED 1.
Wherein, the 26th resistance R26, the 12nd capacitance C12, the 13rd capacitance C13 and the 14th capacitance C14 are
The power supply circuit of microcontroller U2 provides stable operating voltage for microcontroller U2；The Light-emitting diode LED 1 is micro-control
The work light of device U2 processed is exported the work state information of Current microcontrollers U2 by the Light-emitting diode LED 1, made
User can quickly judge the service condition of Current microcontrollers U2, such as be always on and represent its normal work, often go out and represent its stopping
Work, flicker represent its operation irregularity etc.；The 27th resistance R27, the 28th resistance R28, the 29th resistance
R29, the 30th resistance R30, the 15th capacitance C15 and burn-in receptacle CN2 are burn recording software circuit, realize the burning of software program
Erasable operation improves the flexibility of microcontroller U2 applications.
It should be noted, remaining component of non-label in figure, such as resistance, capacitance and zener diode, be micro-control
The conventional component of device U2 and current constant control chip U1 peripheries processed operating circuit, is the prior art, connects pass to it herein
System does not repeat.
Constant-current control circuit 10 is dimmed based on above-mentioned zone, the present invention correspondingly provides a kind of driving power, including shell,
Pcb board is provided in the shell, local dimming constant-current control circuit 10 as described above is provided on the pcb board, due to
The local dimming constant-current control circuit 10 has been described in detail above, has not been described further herein.
The present invention correspondingly provides a kind of television set, including driving power as described above, due to above to the drive
Dynamic power supply is described in detail, and is not described further herein.
To more fully understand the control process of local dimming constant-current control circuit 10 provided by the invention, below in conjunction with Fig. 3
And Fig. 4, it lifts Application Example and the course of work of the local dimming constant-current control circuit 10 is illustrated：
AC-input voltage provides 48V and 12V voltages, wherein 12V is to mainboard 30 and perseverance after AD-DC conversion circuits after booting
Flow control chip U1 powers, and 12V obtains 3.3V through three terminal regulator and powers to microcontroller U2.After mainboard 30 works, ON/ is provided
OFF, ENA, SCK, CSB, etc. control signal, microcontroller U2 start to work, give constant current control by SCL, SDA, VSYNC data line
To the metal-oxide-semiconductor Q18 in boosting unit 121, boosting unit 121 is opened by coremaking piece U1, current constant control chip U1 output driving pulse DRV
Beginning work, energy storage inductor L1 start charge and discharge, and energy exports perseverance after the second diode D2 and the 4th capacitance C4 rectifying and wave-filterings
Fixed DC voltage is powered to backlight lamp bar 40, after through lamp bar negative terminal return current constant control chip U1, current constant control chip
U1 detects builtin voltage, i.e. generation detection voltage, judges current boost according to the detection voltage according to the control signal received
Whether the voltage that unit 121 exports meets lamp bar specification, if the brownout that boosting unit 121 exports, current constant control chip
U1 increases the duty ratio of driving pulse, the voltage raising for exporting it, if the overtension that boosting unit 121 exports, constant current
It chip U1 is controlled to reduce the duty ratio of big driving pulse, reduces its voltage exported, 40 specification of backlight lamp bar is met with this,
When needing local dimming, dimming commands are occurred by VSYNC by mainboard 30 and give microcontroller U2, after microcontroller U2 conversions
It is exported by SCL, SDA, VSYNC data line and gives current constant control chip U1, corresponding channel is controlled by current constant control chip U1, is adjusted
The grid duty ratio of corresponding channel dimmer switch pipe inside whole current constant control chip U1 changes the size of current of the channel, meets
The requirement of local dimming.
In conclusion in local dimming constant-current control circuit provided by the invention, driving power and television set, the region
Light modulation constant-current control circuit is connect with AC-DC conversion circuits, mainboard and backlight lamp bar, including dimming controlling module and built-in
The constant-current driven module of boost control circuit and multichannel dimmer switch pipe；The driving of mainboard output is received by dimming controlling module
Signal and dim signal are simultaneously transmitted to constant-current driven module, and the constant-current driven module turns AC-DC according to the drive signal
The first voltage for changing circuit output boosts to after predeterminated voltage output to backlight lamp bar, and adjust and correspond to according to the dim signal
The grid duty ratio of channel dimmer switch pipe, and then adjust the size of current of corresponding channel.By using built-in boosting rectifier control electricity
Road and the constant-current driven module of dimmer switch pipe effectively optimize the framework of local dimming light source, reduce earth loop crosstalk and draw
The problem of electric current is unstable is played, while effectively reduces pcb board area, achievees the purpose that reduce cost.
It, can according to the technique and scheme of the present invention and its hair it is understood that for those of ordinary skills
Bright design is subject to equivalent substitution or change, and all these changes or replacement should all belong to the guarantor of appended claims of the invention
Protect range.
Claims (10)
1. a kind of local dimming constant-current control circuit, connect, feature exists with AC-DC conversion circuits, mainboard and backlight lamp bar
In the constant-current driven module including dimming controlling module and built-in boost control circuit and multichannel dimmer switch pipe；By adjusting
The drive signal and dim signal of the reception mainboard output of photocontrol module are simultaneously transmitted to constant-current driven module, and the constant current drives mould
Root tuber is exported after the first voltage that AC-DC conversion circuits export is boosted to predeterminated voltage according to the drive signal to backlight
Item, and according to the grid duty ratio of dim signal adjusting corresponding channel dimmer switch pipe, and then adjust the electricity of corresponding channel
Flow size.
2. local dimming constant-current control circuit according to claim 1, which is characterized in that the constant-current driven module includes
The constant-current control unit of boosting unit and built-in boost control circuit and multichannel dimmer switch pipe；By the constant-current control unit
According to the drive signal output driving pulse to boosting unit, the boosting unit is driven to start to work；The boosting unit
It is exported after the first voltage that AC-DC conversion circuits export is boosted to predeterminated voltage to backlight lamp bar；The constant-current control unit
The grid duty ratio of corresponding channel dimmer switch pipe is adjusted also according to the dim signal, and then the electric current for adjusting corresponding channel is big
It is small.
3. local dimming constant-current control circuit according to claim 2, which is characterized in that the constant-current control unit also root
According to the real work voltage generation detection voltage of backlight lamp bar, the practical work of current backlight lamp bar is judged according to the detection voltage
Make whether voltage is predeterminated voltage, and the duty ratio of the driving pulse is adjusted according to judging result.
4. local dimming constant-current control circuit according to claim 1, which is characterized in that the dimming controlling module includes
Dimming control unit and data transmission unit receive the drive signal of mainboard output by the dimming control unit and light modulation are believed
Number, and pass through the data transmission unit and export the drive signal and dim signal to constant-current driven module.
5. local dimming constant-current control circuit according to claim 2, which is characterized in that the constant-current control unit includes
Current constant control chip, the 1st foot connection boosting unit of the current constant control chip, the 5th foot of the current constant control chip,
6th foot and the 7th foot are all connected with the dimming controlling module, and the 14th foot to the 20th foot of the current constant control chip is all connected with backlight
Lamp bar.
6. local dimming constant-current control circuit according to claim 5, which is characterized in that the boosting unit includes electricity
Sense, first resistor, second resistance, 3rd resistor, the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance,
Nine resistance, the tenth resistance, the first capacitance, the second capacitance, third capacitance, the 4th capacitance, the first diode, the second diode,
One zener diode, the second zener diode and metal-oxide-semiconductor；
The first voltage output terminal of one end connection AC-DC conversion circuits of the inductance, the other end connection second of the inductance
The drain electrode of the anode, metal-oxide-semiconductor of diode and one end of the 8th resistance；The cathode of second diode connects the one of the second capacitance
End, the anode and backlight lamp bar of the anode of third capacitance, the 4th capacitance；The cathode of the third capacitance and the cathode of the 4th capacitance
It is grounded；The other end of second capacitance connects the other end of the 8th resistance and one end of the 9th resistance；Described 9th
The other end of resistance connects one end of the 8th resistance and one end of the first capacitance；The other end connection second of first capacitance is steady
Press one end, one end of the 7th resistance and the source electrode of metal-oxide-semiconductor of the cathode of diode, one end of the 5th resistance, the 6th resistance；It is described
The anode of second zener diode, the other end of the 5th resistance, the other end of the 6th resistance and the other end of the 7th resistance connect
Ground；The metal-oxide-semiconductor grid connection the cathode of the first zener diode, the anode of the first diode, second resistance one end and
One end of 3rd resistor；One end of anode the 5th resistance of connection of first zener diode, the volume other end of 3rd resistor
With one end of the 4th resistance；One end of the cathode connection first resistor of first diode；The other end of the first resistor
Connect the other end of second resistance and one end of the tenth resistance；The other end of 4th resistance connects the current constant control chip
The 22nd foot；The other end of tenth resistance connects the 1st foot of the current constant control chip.
7. local dimming constant-current control circuit according to claim 4, which is characterized in that the dimming control unit includes
Microcontroller, the 7th foot, the 12nd foot and the 15th foot of the microcontroller are connect with mainboard, the 2nd foot of the microcontroller, the 3rd
Foot and the 19th foot are all connected with the constant-current driven module.
8. local dimming constant-current control circuit according to claim 7, which is characterized in that the data transmission unit includes
11st resistance and the 12nd resistance；2nd foot of one end connection microcontroller of the 11st resistance, the 11st resistance
The other end connect the constant-current driven module；3rd foot of one end connection microcontroller of the 12nd resistance, the described tenth
The other end of two resistance connects the constant-current driven module.
9. a kind of driving power including shell, pcb board is provided in the shell, which is characterized in that set on the pcb board
Just like the local dimming constant-current control circuit described in claim 1-8 any one.
10. a kind of television set, which is characterized in that including driving power as claimed in claim 9.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810126819.0A CN108231014B (en) | 2018-02-08 | 2018-02-08 | Regional dimming constant current control circuit, driving power supply and television |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810126819.0A CN108231014B (en) | 2018-02-08 | 2018-02-08 | Regional dimming constant current control circuit, driving power supply and television |
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| CN108231014B CN108231014B (en) | 2020-08-04 |
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| CN201810126819.0A Active CN108231014B (en) | 2018-02-08 | 2018-02-08 | Regional dimming constant current control circuit, driving power supply and television |
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| CN109949753A (en) * | 2019-04-24 | 2019-06-28 | 深圳创维－Rgb电子有限公司 | A kind of power supply unit of backlight |
| CN112216245A (en) * | 2020-10-09 | 2021-01-12 | 深圳创维－Rgb电子有限公司 | Adjusting circuit and method for module backlight lamp bar of television |
| CN112333889A (en) * | 2020-11-25 | 2021-02-05 | 深圳创维－Rgb电子有限公司 | Double-direct-drive LED power circuit and television |
| CN112584573A (en) * | 2020-12-11 | 2021-03-30 | 浙江金缘光电有限公司 | Seven-primary-color LED mixed light source and drive control circuit thereof |
| CN114023273A (en) * | 2021-11-22 | 2022-02-08 | 深圳创维－Rgb电子有限公司 | Local dimming driving circuit, method and system and electronic equipment |
| CN114420054A (en) * | 2021-12-23 | 2022-04-29 | 深圳创维－Rgb电子有限公司 | Backlight constant-current driving circuit, switching power supply and display device |
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