CN201946273U - Backlight source control circuit and led display screen - Google Patents
Backlight source control circuit and led display screen Download PDFInfo
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- CN201946273U CN201946273U CN2011200766811U CN201120076681U CN201946273U CN 201946273 U CN201946273 U CN 201946273U CN 2011200766811 U CN2011200766811 U CN 2011200766811U CN 201120076681 U CN201120076681 U CN 201120076681U CN 201946273 U CN201946273 U CN 201946273U
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Abstract
The embodiment of the utility model discloses a backlight source control circuit and an LED display screen and belongs to the technical field of LED display. The technical problem that the backlight source control circuit in the prior art has a complicated structure is solved. The backlight source control circuit comprises a control chip, a triode and at least two branch circuits connected with a collector of the triode; the control chip comprises at least two groups of current feedback pins, voltage sampling pins and comparators, corresponding to each branch circuit; a base of the triode is used for receiving control signals and the emitter of the triode is grounded; each branch circuit comprises a feedback resistor, a first divider resistor, a second divider resistor; one end of the feedback resistor is grounded and the other end of the divider resistor is connected with the current feedback pin of the control chip; the first divider resistor is serially connected between the voltage sampling pin and the current feedback pin of the control chip; the second divider resistor is serially connected between the voltage sampling pin and the collector of the triode; and the voltage sampling pin is connected with the comparator. The backlight source control circuit provided by the utility model is applied to the LED display screen.
Description
Technical field
The utility model belongs to LED display technique field, is specifically related to a kind of backlight control circuit and LED display.
Background technology
Continuous development along with electronic technology, light emitting diode (LED) display screen has two kinds of display modes of two and three dimensions (2D and 3D), the conversion of 2D/3D realizes by the size of current of adjusting backlight, promptly requires control chip must export the steady current of two kinds of different sizes to backlight.Conventional at present control chip can only be exported a kind of steady current, so need the outer circuit that adds to realize two kinds of conversions between the electric current.
As shown in Figure 1, there is the multichannel output current in present LED-backlit source, is example with the OZ9967 chip, and it provides six road output currents for backlight.The additional circuit that is used for switching current also is divided into six branch roads, with the first via is example, the end ground connection of feedback resistance R11, the other end links to each other with the current feedback pin IFB1 of control chip, produce feedback voltage, wherein IFB1 connects with the first via output current of backlight, and promptly first via output current is flowed through and flowed back to IFB1 after the backlight, so IFB1 has reflected the size of first via output current.Voltage sample pin ISEN1 on the control chip is used to gather feedback voltage, and links to each other with the comparer of control chip inside.When LED display need be when 2D shows that convert 3D to shows, can be by the base stage output high level (STD control signal) of digital circuit board to triode V1, make collector and the emitter conducting of triode V1, it is in parallel with R12 afterwards jointly as feedback resistance just to be equivalent to former feedback resistance R11 this moment, and the resistance of feedback resistance is diminished.The reducing of feedback resistance resistance causes feedback voltage to reduce, when comparer detects voltage that voltage sample pin ISEN1 collects less than reference voltage, will increase output current, thus the rising feedback voltage, and the feedback voltage that collects up to ISEN1 equates with reference voltage.
If show that from 3D convert 2D to shows that then by the base stage output low level of digital circuit board to triode V1, its process is opposite with said process, and other five the tunnel and the first via identical.The output current of backlight was 60mA when 2D showed usually, and the output current of backlight was 120mA when 3D showed, R11 is chosen for 5.1 Ω, and the feedback voltage (reference voltage) when then 2D shows is 0.3V; If R12 equates that with the R11 resistance feedback voltage when then 3D shows also is 0.3V, equates with reference voltage.
In realizing process of the present utility model, the inventor finds that there are the following problems at least in the prior art: adopt the method that reduces feedback resistance to reduce feedback voltage, make the electric current big (60mA) that flows through triode, so can't control six branch roads by a triode, and a triode can only all be set on each branch road.Six triodes of STD control signal conducting simultaneously in order to allow digital circuit board send also need increase the one-level amplifying circuit on digital circuit board, amplify control signal.Existing backlight control circuit will all be provided with a triode on each branch road, and will increase amplifying circuit, causes the baroque technical matters of backlight control circuit.
The utility model content
The utility model embodiment provides more simple backlight control circuit of a kind of structure and LED display.
For achieving the above object, embodiment of the present utility model adopts following technical scheme:
This backlight control circuit comprises a control chip, a triode, and at least two branch roads that link to each other with the collector of described triode; Described control chip comprises and the corresponding two group current feedback pin of each described branch road, voltage sample pin and comparer at least; The base stage of wherein said triode is used to receive control signal, its grounded emitter; Each described branch road comprises feedback resistance, first divider resistance and second divider resistance; One end ground connection of described feedback resistance, the other end links to each other with the current feedback pin of described control chip; Described first divider resistance is series between the voltage sample pin and described current feedback pin of control chip; Described second divider resistance is series between the collector of described voltage sample pin and described triode, perhaps is series between the emitter and ground wire of described triode; Described voltage sample pin links to each other with described comparer.
This LED display comprises backlight control circuit, and described backlight control circuit comprises a control chip, a triode, and at least two branch roads that link to each other with the collector of described triode; Described control chip comprises and the corresponding two group current feedback pin of each described branch road, voltage sample pin and comparer at least; The base stage of wherein said triode is used to receive control signal, its grounded emitter; Each described branch road comprises feedback resistance, first divider resistance and second divider resistance; One end ground connection of described feedback resistance, the other end links to each other with the current feedback pin of described control chip; Described first divider resistance is series between the voltage sample pin and described current feedback pin of control chip; Described second divider resistance is series between the collector of described voltage sample pin and described triode, perhaps is series between the emitter and ground wire of described triode; Described voltage sample pin links to each other with described comparer.
Each branch road adopts the mode dividing potential drop of resistance in series among the utility model embodiment, reduces the voltage that the voltage sample pin is gathered.Be specially, the current feedback pin produces feedback voltage by feedback resistance, and gathers feedback voltage by the voltage sample pin by first divider resistance.When LED display 2D showed, the not conducting of the collector of triode and emitter was not gathered feedback voltage so first divider resistance can not influence the voltage sample pin.When LED display need be when 2D shows that convert 3D to shows, control end by digital circuit board is exported high level to the base stage of triode, make the collector and the emitter conducting of triode, this moment, two divider resistances just were series between current feedback pin and the ground wire, feedback voltage then is split on two divider resistances, can only collect part feedback voltage on second divider resistance so be connected in two voltage sample pin between the divider resistance.
Compared with prior art, technique scheme that the utility model provides has following advantage: because the utility model embodiment adopts the mode of string resistance dividing potential drop to reduce the voltage that the voltage sample pin is gathered, the dividing potential drop effect is only relevant with the ratio of two divider resistances, so can use the very big resistance of resistance as divider resistance, the electric current that flows through triode and two divider resistances like this is just very little, a plurality of branch roads just can be by a triode control, need not increases amplifying circuit on digital circuit board, so solved the baroque technical matters of existing control circuit.
Description of drawings
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, to do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below, apparently, accompanying drawing in describing below only is embodiment more of the present utility model, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the synoptic diagram of existing backlight control circuit;
The synoptic diagram of the backlight control circuit that Fig. 2 is provided for embodiment 1 of the present utility model;
The synoptic diagram of the backlight control circuit that Fig. 3 is provided for embodiment 2 of the present utility model.
Embodiment
Below in conjunction with the accompanying drawing among the utility model embodiment, the technical scheme among the utility model embodiment is clearly and completely described, obviously, described embodiment only is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, the every other embodiment that those of ordinary skills are obtained under the prerequisite of not paying creative work belongs to the scope that the utility model is protected.
The utility model embodiment provides a kind of backlight control circuit and LED display.
Embodiment 1:
As shown in Figure 2, the backlight control circuit that the utility model embodiment is provided comprises a control chip, a triode, and at least two branch roads that link to each other with the collector of triode V1; Control chip comprises and the corresponding two group current feedback pin of each branch road, voltage sample pin and comparer at least; Wherein the base stage of triode V1 links to each other with digital circuit board, is used to receive control signal, its grounded emitter; Each branch road comprises feedback resistance, first divider resistance and second divider resistance; One end ground connection of feedback resistance, the other end links to each other with the current feedback pin of control chip; First divider resistance is series between the voltage sample pin and current feedback pin of control chip; Second divider resistance is series between the collector of voltage sample pin and triode V1; The voltage sample pin links to each other with comparer.
As a preferred version, the current-limiting resistance R01 that connects between the base stage of triode V1 and digital circuit board prevents that the electric current of control signal is excessive, damages triode V1; And between triode V1 and current-limiting resistance R01, filter capacitor C01 is set, be used to filter undesired signal, and divider resistance R02, be used to prevent that the voltage of control signal is excessive, damage triode V1.
Each branch road adopts the mode dividing potential drop of resistance in series among the utility model embodiment, reduces the voltage that the voltage sample pin is gathered.With first branch road is example, and current feedback pin IFB1 produces feedback voltage by feedback resistance R1, and gathers feedback voltage by voltage sample pin ISEN1 by the first divider resistance R13.When LED display 2D showed, the not conducting of the collector of triode V1 and emitter was not gathered feedback voltage so the first divider resistance R13 can not influence voltage sample pin ISEN1.When LED display need be when 2D shows that convert 3D to shows, control end by digital circuit board is exported high level to the base stage of triode V1, make collector and the emitter conducting of triode V1, this moment, two divider resistances just were series between current feedback pin and the ground wire, feedback voltage then is split on two divider resistances, can only collect part feedback voltage on the second divider resistance R14 so be connected in two voltage sample pin between the divider resistance.
Compared with prior art, technique scheme that the utility model provides has following advantage: because the utility model embodiment adopts the mode of string resistance dividing potential drop to reduce the voltage that the voltage sample pin is gathered, the dividing potential drop effect is only relevant with the ratio of two divider resistances, so can use the very big resistance of resistance as divider resistance, the electric current that flows through triode and two divider resistances like this is just very little, a plurality of branch roads just can be by a triode control, need not increases amplifying circuit on digital circuit board, so solved the baroque technical matters of existing control circuit.
In addition, because six branch roads of existing backlight control circuit are regulated respectively by six triodes, so if six triode consistance are bad, be easy to cause the electric current on every road all different, promptly six road current imbalances cause brightness of image inhomogeneous.The backlight control circuit that the utility model embodiment provides has also been avoided the problem of above-mentioned current unevenness weighing apparatus by six branch roads of a triode control.
Among the utility model embodiment, the resistance of first divider resistance and second divider resistance is far longer than feedback resistance.With first branch road is example, after the collector of triode V1 and the emitter conducting, is actually after the first divider resistance R13 and the second divider resistance R14 series connection, in parallel with feedback resistance R11 again, also can reduce the resistance of feedback resistance, causes feedback voltage to reduce.If the resistance of the first divider resistance R13 and the second divider resistance R14 is far longer than feedback resistance R11, promptly than the first divider resistance R13 and the second divider resistance R14, the resistance of feedback resistance R11 can be ignored, the variable quantity of feedback resistance resistance also can be ignored before and after then in parallel, also just can not influence feedback voltage.
Among the utility model embodiment, the resistance of first divider resistance and second divider resistance equates.With the OZ9967 chip is example, and the output current of backlight was 60mA when 2D showed, the output current of backlight was 120mA when 3D showed, the output current of backlight was the twice that 2D shows when promptly 3D showed.If the resistance of the first divider resistance R13 and the second divider resistance R14 equates, then the voltage that collects of voltage sample pin ISEN1 just in time is half of feedback voltage (reference voltage), adjusting by comparer, during twice when the output current of backlight is increased to 2D and shows, the voltage that voltage sample pin ISEN1 collects also just in time equals reference voltage.
Among the utility model embodiment, the resistance of first divider resistance and second divider resistance is 1K, and the resistance of feedback resistance is 5.1 Ω.With the OZ9967 chip is example, and the output current of backlight was 60mA when 2D showed, the output current of backlight was 120mA when 3D showed, then feedback voltage is 0.3V.The first divider resistance R13 and the second divider resistance R14 elect 1K as, and the output current of backlight was 120mA when 3D was shown, and was far longer than 5.1 Ω of feedback resistance R11, can not influence feedback voltage.
Among the utility model embodiment, the quantity of branch road is six.The OZ9967 chip is a control chip relatively more commonly used, and it provides six road output currents for backlight, so the backlight control circuit that adds also has six branch roads.Certainly, the quantity of branch road is not limited to six the tunnel by the number of pins decision of control chip.
Embodiment 2:
Present embodiment is substantially the same manner as Example 1, and its difference is: as shown in Figure 3, in the present embodiment, the second divider resistance R03 is series between the emitter and ground wire of triode.After the collector and emitter conducting of triode V1, still two divider resistance series connection, effect is identical with embodiment 1.Six second divider resistances on each branch road are become one second divider resistance on the main road, further simplify the structure of backlight control circuit.
Embodiment 3:
As shown in Figure 2, the LED display that the utility model embodiment is provided comprises backlight control circuit, and this backlight control circuit comprises a control chip, a triode, and at least two branch roads that link to each other with the collector of triode V1; Control chip comprises and the corresponding two group current feedback pin of each branch road, voltage sample pin and comparer at least; Wherein the base stage of triode V1 links to each other with digital circuit board, is used to receive control signal, its grounded emitter; Each branch road comprises feedback resistance, first divider resistance and second divider resistance; One end ground connection of feedback resistance, the other end links to each other with the current feedback pin of control chip; First divider resistance is series between the voltage sample pin and current feedback pin of control chip; Second divider resistance is series between the collector of voltage sample pin and triode V1; The voltage sample pin links to each other with comparer.
As a preferred version, the current-limiting resistance R01 that connects between the base stage of triode V1 and digital circuit board prevents that the electric current of control signal is excessive, damages triode V1; And between triode V1 and current-limiting resistance R01, filter capacitor C01 is set, be used to filter undesired signal, and divider resistance R02, be used to prevent that the voltage of control signal is excessive, damage triode V1.
Each branch road adopts the mode dividing potential drop of resistance in series among the utility model embodiment, reduces the voltage that the voltage sample pin is gathered.With first branch road is example, and current feedback pin IFB1 produces feedback voltage by feedback resistance R1, and gathers feedback voltage by voltage sample pin ISEN1 by the first divider resistance R13.When LED display 2D showed, the not conducting of the collector of triode V1 and emitter was not gathered feedback voltage so the first divider resistance R13 can not influence voltage sample pin ISEN1.When LED display need be when 2D shows that convert 3D to shows, control end by digital circuit board is exported high level to the base stage of triode V1, make collector and the emitter conducting of triode V1, this moment, two divider resistances just were series between current feedback pin and the ground wire, feedback voltage then is split on two divider resistances, can only collect part feedback voltage on the second divider resistance R14 so be connected in two voltage sample pin between the divider resistance.
Compared with prior art, technique scheme that the utility model provides has following advantage: because the utility model embodiment adopts the mode of string resistance dividing potential drop to reduce the voltage that the voltage sample pin is gathered, the dividing potential drop effect is only relevant with the ratio of two divider resistances, so can use the very big resistance of resistance as divider resistance, the electric current that flows through triode and two divider resistances like this is just very little, a plurality of branch roads just can be by a triode control, need not increases amplifying circuit on digital circuit board, so solved the baroque technical matters of existing control circuit.
In addition, because six branch roads of existing backlight control circuit are regulated respectively by six triodes, so if six triode consistance are bad, be easy to cause the electric current on every road all different, promptly six road current imbalances cause brightness of image inhomogeneous.The backlight control circuit that the utility model embodiment provides has also been avoided the problem of above-mentioned current unevenness weighing apparatus by six branch roads of a triode control.
Among the utility model embodiment, the resistance of first divider resistance and second divider resistance is far longer than feedback resistance.
Among the utility model embodiment, the resistance of first divider resistance and second divider resistance equates.
Among the utility model embodiment, the resistance of first divider resistance and second divider resistance is 1K, and the resistance of feedback resistance is 5.1 Ω.
Among the utility model embodiment, the quantity of branch road is six.
Because the utility model embodiment has identical technical characterictic with the Handling device that above-mentioned the utility model embodiment is provided, so also can produce identical technique effect, solves identical technical matters.
Embodiment 4:
Present embodiment is substantially the same manner as Example 3, and its difference is: in the present embodiment, second divider resistance is series between the emitter and ground wire of triode.After the collector and emitter conducting of triode, still two divider resistance series connection, effect is identical with embodiment 3.Six second divider resistances on each branch road are become one second divider resistance on the main road, further simplify the structure of backlight control circuit.
The above; it only is embodiment of the present utility model; but protection domain of the present utility model is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the utility model discloses; the variation that can expect easily or replacement all should be encompassed within the protection domain of the present utility model.Therefore, protection domain of the present utility model should be as the criterion with the protection domain of claim.
Claims (8)
1. backlight control circuit is characterized in that: comprise a control chip, a triode, and at least two branch roads that link to each other with the collector of described triode;
Described control chip comprises and the corresponding two group current feedback pin of each described branch road, voltage sample pin and comparer at least; Wherein
The base stage of described triode is used to receive control signal, its grounded emitter;
Each described branch road comprises feedback resistance, first divider resistance and second divider resistance; One end ground connection of described feedback resistance, the other end links to each other with the current feedback pin of described control chip; Described first divider resistance is series between the voltage sample pin and described current feedback pin of control chip; Described second divider resistance is series between the collector of described voltage sample pin and described triode, perhaps is series between the emitter and ground wire of described triode; Described voltage sample pin links to each other with described comparer.
2. backlight control circuit according to claim 1 is characterized in that: the resistance of described first divider resistance and described second divider resistance is far longer than described feedback resistance.
3. backlight control circuit according to claim 1 is characterized in that: the resistance of described first divider resistance and described second divider resistance equates.
4. backlight control circuit according to claim 1 is characterized in that: the quantity of described branch road is six.
5. LED display, it is characterized in that: comprise backlight control circuit, described backlight control circuit comprises a control chip, a triode, and at least two branch roads that link to each other with the collector of described triode;
Described control chip comprises and the corresponding two group current feedback pin of each described branch road, voltage sample pin and comparer at least; Wherein
The base stage of described triode is used to receive control signal, its grounded emitter;
Each described branch road comprises feedback resistance, first divider resistance and second divider resistance; One end ground connection of described feedback resistance, the other end links to each other with the current feedback pin of described control chip; Described first divider resistance is series between the voltage sample pin and described current feedback pin of control chip; Described second divider resistance is series between the collector of described voltage sample pin and described triode, perhaps is series between the emitter and ground wire of described triode; Described voltage sample pin links to each other with described comparer.
6. LED display according to claim 5 is characterized in that: the resistance of described first divider resistance and described second divider resistance is far longer than described feedback resistance.
7. LED display according to claim 5 is characterized in that: the resistance of described first divider resistance and described second divider resistance equates.
8. LED display according to claim 5 is characterized in that: the quantity of described branch road is six.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200766811U CN201946273U (en) | 2011-03-22 | 2011-03-22 | Backlight source control circuit and led display screen |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200766811U CN201946273U (en) | 2011-03-22 | 2011-03-22 | Backlight source control circuit and led display screen |
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| CN201946273U true CN201946273U (en) | 2011-08-24 |
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| CN2011200766811U Expired - Fee Related CN201946273U (en) | 2011-03-22 | 2011-03-22 | Backlight source control circuit and led display screen |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103927959A (en) * | 2013-12-30 | 2014-07-16 | 上海中航光电子有限公司 | Voltage adjusting circuit of display device, and display device |
| CN106710531A (en) * | 2017-01-19 | 2017-05-24 | 深圳市华星光电技术有限公司 | Backlight control circuit and electronic device |
-
2011
- 2011-03-22 CN CN2011200766811U patent/CN201946273U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103927959A (en) * | 2013-12-30 | 2014-07-16 | 上海中航光电子有限公司 | Voltage adjusting circuit of display device, and display device |
| CN103927959B (en) * | 2013-12-30 | 2016-12-07 | 上海中航光电子有限公司 | The voltage regulator circuit of display device, display device |
| CN106710531A (en) * | 2017-01-19 | 2017-05-24 | 深圳市华星光电技术有限公司 | Backlight control circuit and electronic device |
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