CN202434187U - Adjusting circuit for backlight brightness of LED - Google Patents
Adjusting circuit for backlight brightness of LED Download PDFInfo
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- CN202434187U CN202434187U CN2011204192197U CN201120419219U CN202434187U CN 202434187 U CN202434187 U CN 202434187U CN 2011204192197 U CN2011204192197 U CN 2011204192197U CN 201120419219 U CN201120419219 U CN 201120419219U CN 202434187 U CN202434187 U CN 202434187U
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Abstract
The utility model discloses an adjusting circuit for backlight brightness of LEDs. The adjusting circuit comprises an LED lamp string circuit for providing backlight, a master control IC circuit for adjusting backlight brightness of the LED lamp string circuit based on voltage reference, and a voltage reference precision setting circuit for providing the voltage reference to the master control IC circuit, wherein the voltage reference precision setting circuit further comprises a first switch unit, a second switch unit and a voltage precision setting unit. The adjusting circuit for backlight brightness of LEDs enables the precision of adjusting backlight brightness of LEDs to be improved, enables errors to be minimized and helps to prolong the service life of LEDs.
Description
Technical field
The utility model relates to the LED-backlit technical field, specifically, relates to a kind of regulating circuit of LED-backlit brightness.
Background technology
At present, the LCD TV of LED-backlit has high quality graphic, energy-conservation, long-life, contrast advantages of higher.The market of the LCD TV of LED-backlit enlarges rapidly, is used for LED luminescence efficiency backlight and improves rapidly, and electric current is increasing, and cost descends rapidly.
The brightness regulation of LED-backlit generally is to carry out through electric current, because cost and structural requirement, the LED electric current is increasing, and is therefore higher to the Current Regulation accuracy requirement.
Present LED-backlit solution precision is generally 3% ~ 5%, and when maximum current, the Error Absolute Value of electric current is very big, does not reach the big electric current LED current precision requirement of usefulness backlight, influences the LED life-span.
In view of this, the control method that needs a kind of new LED-backlit brightness.
The utility model content
The purpose of the utility model provides a kind of regulating circuit of LED-backlit brightness, and is low with the precision that solves LED-backlit brightness regulation in the prior art, error is big, thereby influences the LED problem in serviceable life.
For achieving the above object, the technical scheme that the utility model is taked is following:
A kind of regulating circuit of LED-backlit brightness; Comprise the LED lamp string road that provides backlight; Regulate the master control IC circuit of the backlight illumination on LED lamp string road according to reference voltage; The reference voltage precision set circuit of this reference voltage to this master control IC circuit is provided, and wherein, this reference voltage precision set circuit comprises: first switch element, second switch unit and voltage accuracy setup unit;
For providing first switch element of first voltage, this voltage accuracy setup unit comprises: pwm signal input end, dc voltage input end and first electronic switch; This pwm signal input end is electrically connected the control end of this first electronic switch; This dc voltage input end is electrically connected the input end of this first electronic switch, and the voltage signal that this first switch element is imported according to this pwm signal input end and dc voltage input end provides first voltage via the output terminal of this first electronic switch for this voltage accuracy setup unit;
For providing the second switch unit of second voltage, this voltage accuracy setup unit comprises: the DIM signal input part and second electronic switch; This DIM signal input part is electrically connected the control end of this second electronic switch; The input end grounding of this second electronic switch, this second switch unit provides second voltage via the output terminal of this second electronic switch for this voltage accuracy setup unit according to the voltage signal of this DIM signal input part input;
Voltage accuracy setup unit according to this first voltage or this second voltage output reference voltage comprises: according to the votage control switch of first voltage or second voltage output tertiary voltage, with the voltage divider of this tertiary voltage dividing potential drop and with the reference voltage output end of the tertiary voltage after the dividing potential drop as reference voltage output; This votage control switch comprises anode, negative electrode and reference edge; The negative electrode of this votage control switch is electrically connected with the output terminal of first electronic switch, the output terminal of second electronic switch respectively; The plus earth of this votage control switch, reference edge is electrically connected each other with negative electrode and is electrically connected with this reference voltage output end via this voltage divider.
The regulating circuit of described LED-backlit brightness; Wherein, This first switch element also comprises first resistance, second resistance and the 3rd resistance; This pwm signal input end is via the control end of this this first electronic switch of first resistance electrical connection, and this dc voltage input end is via the input end of this first electronic switch of the 3rd resistance electrical connection, and the two ends of this second resistance are electrically connected the control end and the input end of this first electronic switch respectively.
The regulating circuit of described LED-backlit brightness, wherein, this second switch unit also comprises the 4th resistance, this DIM signal input part is electrically connected the control end of this second electronic switch via the 4th resistance.
The regulating circuit of described LED-backlit brightness, wherein, this voltage accuracy setup unit also comprises first filter capacitor and second filter capacitor, this first filter capacitor, one end is electrically connected the reference edge of this votage control switch, other end ground connection; One end of this second filter capacitor is electrically connected this reference voltage output end, other end ground connection.
The regulating circuit of described LED-backlit brightness, wherein, this first electronic switch is a NPN type triode, the control end of this first electronic switch, input end and output terminal are respectively base stage, collector and the emitter of NPN type triode; This second electronic switch is the positive-negative-positive triode, and the control end of this second electronic switch, input end and output terminal are respectively base stage, collector and the emitter of positive-negative-positive triode.
The regulating circuit of described LED-backlit brightness, wherein, this votage control switch is that precision is 1% adjustable shunting reference source TL431.
The regulating circuit of described LED-backlit brightness, wherein, this voltage divider comprises that at least two resistance accuracies are 1% divider resistance.
The regulating circuit of described LED-backlit brightness, wherein, the pwm signal that this pwm signal input end input external circuit provides; The 5V DC voltage that this dc voltage input end input external circuit provides; The DIM direct current dimmer voltage that this DIM signal input part input external circuit provides.
Compared with prior art, the regulating circuit of the LED-backlit brightness that provides of the utility model comprises: provide LED lamp string road backlight, according to reference voltage regulate the backlight illumination on LED lamp string road master control IC circuit, the reference voltage precision set circuit of this reference voltage to this master control IC circuit is provided; Wherein, this reference voltage precision set circuit further comprises: first switch element, second switch unit and voltage accuracy setup unit.The regulating circuit of the LED-backlit brightness through the utility model can improve the precision of LED-backlit brightness regulation, reduces error, prolongs LED serviceable life.
Description of drawings
Fig. 1 is the circuit theory diagrams of regulating circuit of the LED-backlit brightness of the utility model.
Embodiment
The utility model provides a kind of regulating circuit of LED-backlit brightness.For the purpose, technical scheme and the effect that make the utility model is clearer, clear and definite, below with reference to accompanying drawing, the specific embodiment that develops simultaneously is to the utility model further explain.
See also Fig. 1, it is the circuit theory diagrams of regulating circuit of the LED-backlit brightness of the utility model.As shown in the figure, the regulating circuit of this LED-backlit brightness comprises: LED lamp string road 10 backlight is provided; Regulate the master control IC circuit 20 of the backlight illumination on LED lamp string road 10 according to reference voltage; The reference voltage precision set circuit 30 of this reference voltage to this master control IC circuit 20 is provided.
Wherein, this reference voltage precision set circuit 30 comprises: first switch element 32, second switch unit 34 and voltage accuracy setup unit 36.
This first switch element 32 is used to this voltage accuracy setup unit 36 first voltage is provided.Particularly, first switch element 32 comprises: pwm signal input end 321, dc voltage input end 322, first electronic switch 323 (like NPN type triode), first resistance 324, second resistance 325 and the 3rd resistance 326.This pwm signal input end 321 is electrically connected the control end b1 (being the base stage of NPN type triode) of this first electronic switch 323 via this first resistance 324.This dc voltage input end 322 is electrically connected the input end c1 (being the collector of NPN type triode) of this first electronic switch 323 via the 3rd resistance 326.The two ends of this second resistance 325 are electrically connected the control end b1 and the input end c1 of this first electronic switch 323 respectively.This first switch element 32 provides first voltage via the output terminal e1 (being the emitter of NPN type triode) of this first electronic switch 323 for this voltage accuracy setup unit 36 according to the voltage signal of this pwm signal input end 321 and dc voltage input end 322 inputs.
This second switch unit 34 is used to this voltage accuracy setup unit 36 second voltage is provided.Particularly, this second switch unit 34 comprises: DIM signal input part 341, the 4th resistance 342 and second electronic switch 343 (like the positive-negative-positive triode).This DIM signal input part 341 is via the control end b2 (being the base stage of triode) of the 4th resistance 342 these second electronic switches 343 of electrical connection, the input end c2 of this second electronic switch 343 (like the collector of positive-negative-positive triode) ground connection.This second switch unit 34 provides second voltage via the output terminal e2 (like the emitter of positive-negative-positive triode) of this second electronic switch 343 for this voltage accuracy setup unit 36 according to the voltage signal of this DIM signal input part input.
This voltage accuracy setup unit 36 is used for according to first voltage or the second voltage output reference voltage to this master control IC circuit 20.Particularly, this voltage accuracy setup unit 36 comprises: according to the votage control switch 361 of first voltage or second voltage output tertiary voltage, with the voltage divider 362 of this tertiary voltage dividing potential drop and with the reference voltage output end 363 of the tertiary voltage after the dividing potential drop as reference voltage output.Wherein, this voltage divider 362 comprises presses end Vin1, Vin2 and dividing potential drop end Vout first, second year, and in the present embodiment, this voltage divider 362 can be and comprises that at least two resistance accuracies are the voltage divider of 1% divider resistance.It is 1% adjustable shunting reference source TL431 that this votage control switch can be precision, and this votage control switch 361 comprises anode K, negative electrode A and reference edge R.The negative electrode A of this votage control switch 361 is electrically connected with the output terminal e1 of first electronic switch 323, the output terminal e2 of second electronic switch 343 respectively.The anode K ground connection of this votage control switch 361, reference edge R is electrically connected each other with negative electrode A and is electrically connected with first year pressure end Vin1 of this voltage divider 362.Pressed end Vin2 ground connection in second year of this voltage divider 362, the dividing potential drop end Vout of this voltage divider 362 is electrically connected with this reference voltage output end 363.
Further; When the regulating circuit of the LED-backlit brightness of present embodiment adopts the PWM dimming mode; This pwm signal input end 321 of this first switch element 32 can be imported the pwm signal that external circuit (figure does not show) provides; The 5V DC voltage that this dc voltage input end 322 input external circuits (figure does not show) provide, this second open the light this DIM signal input part 341 of unit 34 is unsettled.
When the regulating circuit of the LED-backlit brightness of present embodiment adopts the simulation dimming mode; This DIM signal input part 341 of this second switch unit 34 can be imported the DIM direct current dimmer voltage that external circuit (figure does not show) provides, and this pwm signal input end 321 of this first switch element 32 is unsettled.Wherein, this external circuit (figure do not show) can be the machine core board circuit of the LCD TV of LED-backlit.
Further; In the preferred embodiment of the regulating circuit of the LED-backlit brightness of the utility model; Said first resistance 324 is 2K Europe; Said second resistance 325 is 100K Europe, and said the 3rd resistance 326 and the 4th resistance 342 are 1K Europe, and two resistance accuracies that said voltage divider 362 comprises are that the resistance of 1% divider resistance is respectively 5K Europe and 7.5K Europe.
In addition; Can also be provided with and play first electric capacity 364 of considering the ripple pressure stabilization function and second electric capacity 365 of the assorted letter effect of filtering; The two ends of said first electric capacity 364 connect first year respectively presses end Vin1 and ground; The two ends of said second electric capacity 365 connect reference voltage output end 363 respectively and pressed end Vin2 in second year, and in the present embodiment, said first electric capacity 364 and second electric capacity 365 can be selected the electric capacity of 100nF/50V for use.
Introduce the principle of work of regulating circuit of the LED-backlit brightness of the utility model below.
When the regulating circuit of the LED-backlit brightness of present embodiment adopts the PWM dimming mode, these pwm signal input end 321 input pwm signals of this first switch element 32, this second open the light this DIM signal input part 341 of unit 34 is unsettled.Pwm signal is imported the control end b1 of first electronic switch 323 after first resistance, 324 current limlitings, make 323 conductings of first electronic switch.The 5V DC voltage of dc voltage input end 322 inputs is after the step-down of the 3rd resistance 326, and the negative electrode A to votage control switch 361 supplies power through first electronic switch 323.At this moment, votage control switch 361 is 1% 2.5V voltage through reference edge R output accuracy.Because DIM signal input part 341 is unsettled, the 343 not conductings of second electronic switch.The precision of votage control switch 361 output be 1% 2.5V voltage after above-mentioned voltage divider dividing potential drop, to obtain a precision be 1% reference voltage, and export master control IC circuit 20 to via reference voltage output end 363.Master control IC circuit 20 is that 1% reference voltage output light modulation electric current is to LED lamp string road 10, with the backlight illumination of adjusting LED lamp string according to this precision.
When the regulating circuit of the LED-backlit brightness of present embodiment adopts the simulation dimming mode, these DIM signal input part 341 input DIM direct current dimmer voltage of this second switch unit 34, this pwm signal input end 321 of this first switch element 32 is unsettled.After the step-down of DIM direct current dimmer voltage signal that DIM signal input part 341 is introduced through the 4th resistance 342; The voltage (the big 0.6V of output terminal e2 voltage ratio DIM direct current dimmer voltage) of its output terminal of control end b2 control e2 through second electronic switch 343 is with to the negative electrode A of votage control switch 361 power supply.Because pwm signal input end 321 is unsettled, the 323 not conductings of first electronic switch.At this moment, votage control switch 361 is 1% 2.5V voltage through reference edge R output accuracy, makes the ceiling voltage of the output terminal e2 of second electronic switch 343 be set at 2.5V.The output terminal e2 voltage of second electronic switch 343 obtains a precision after voltage divider 362 dividing potential drops be 1% reference voltage, and export master control IC circuit 20 to via reference voltage output end 363.Master control IC circuit 20 is that 1% reference voltage output light modulation electric current is to LED lamp string road 10, with the backlight illumination of adjusting LED lamp string according to this precision.
In sum, the regulating circuit of LED-backlit brightness comprises: provide LED lamp string road backlight, according to reference voltage regulate the backlight illumination on LED lamp string road master control IC circuit, the reference voltage precision set circuit of this reference voltage to this master control IC circuit is provided; Wherein, this reference voltage precision set circuit further comprises: first switch element, second switch unit and voltage accuracy setup unit.The regulating circuit of the LED-backlit brightness through the utility model can improve the precision of LED-backlit brightness regulation, reduces error, prolongs LED serviceable life.
It is understandable that; Concerning those of ordinary skills; Can be equal to replacement or change according to the technical scheme and the utility model design thereof of the utility model, and all these changes or replacement all should belong to the protection domain of the appended claim of the utility model.
Claims (8)
1. the regulating circuit of a LED-backlit brightness; Comprise the LED lamp string road that provides backlight; Regulate the master control IC circuit of the backlight illumination on LED lamp string road according to reference voltage; The reference voltage precision set circuit of this reference voltage to this master control IC circuit is provided, it is characterized in that, this reference voltage precision set circuit comprises: first switch element, second switch unit and voltage accuracy setup unit;
For providing first switch element of first voltage, this voltage accuracy setup unit comprises: pwm signal input end, dc voltage input end and first electronic switch; This pwm signal input end is electrically connected the control end of this first electronic switch; This dc voltage input end is electrically connected the input end of this first electronic switch, and the voltage signal that this first switch element is imported according to this pwm signal input end and dc voltage input end provides first voltage via the output terminal of this first electronic switch for this voltage accuracy setup unit;
For providing the second switch unit of second voltage, this voltage accuracy setup unit comprises: the DIM signal input part and second electronic switch; This DIM signal input part is electrically connected the control end of this second electronic switch; The input end grounding of this second electronic switch, this second switch unit provides second voltage via the output terminal of this second electronic switch for this voltage accuracy setup unit according to the voltage signal of this DIM signal input part input;
Voltage accuracy setup unit according to this first voltage or this second voltage output reference voltage comprises: according to the votage control switch of first voltage or second voltage output tertiary voltage, with the voltage divider of this tertiary voltage dividing potential drop and with the reference voltage output end of the tertiary voltage after the dividing potential drop as reference voltage output; This votage control switch comprises anode, negative electrode and reference edge; The negative electrode of this votage control switch is electrically connected with the output terminal of first electronic switch, the output terminal of second electronic switch respectively; The plus earth of this votage control switch, reference edge is electrically connected each other with negative electrode and is electrically connected with this reference voltage output end via this voltage divider.
2. the regulating circuit of LED-backlit brightness according to claim 1; It is characterized in that; This first switch element also comprises first resistance, second resistance and the 3rd resistance; This pwm signal input end is via the control end of this this first electronic switch of first resistance electrical connection, and this dc voltage input end is via the input end of this first electronic switch of the 3rd resistance electrical connection, and the two ends of this second resistance are electrically connected the control end and the input end of this first electronic switch respectively.
3. the regulating circuit of LED-backlit brightness according to claim 1 is characterized in that, this second switch unit also comprises the 4th resistance, and this DIM signal input part is electrically connected the control end of this second electronic switch via the 4th resistance.
4. the regulating circuit of LED-backlit brightness according to claim 1; It is characterized in that; This voltage accuracy setup unit also comprises first filter capacitor and second filter capacitor, and this first filter capacitor, one end is electrically connected the reference edge of this votage control switch, other end ground connection; One end of this second filter capacitor is electrically connected this reference voltage output end, other end ground connection.
5. the regulating circuit of LED-backlit brightness according to claim 1; It is characterized in that; This first electronic switch is a NPN type triode, and the control end of this first electronic switch, input end and output terminal are respectively base stage, collector and the emitter of NPN type triode; This second electronic switch is the positive-negative-positive triode, and the control end of this second electronic switch, input end and output terminal are respectively base stage, collector and the emitter of positive-negative-positive triode.
6. the regulating circuit of LED-backlit brightness according to claim 1 is characterized in that, this votage control switch is that precision is 1% adjustable shunting reference source TL431.
7. the regulating circuit of LED-backlit brightness according to claim 1 is characterized in that, this voltage divider comprises that at least two resistance accuracies are 1% divider resistance.
8. the regulating circuit of LED-backlit brightness according to claim 1 is characterized in that, the pwm signal that this pwm signal input end input external circuit provides; The 5V DC voltage that this dc voltage input end input external circuit provides; The DIM direct current dimmer voltage that this DIM signal input part input external circuit provides.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204192197U CN202434187U (en) | 2011-10-28 | 2011-10-28 | Adjusting circuit for backlight brightness of LED |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204192197U CN202434187U (en) | 2011-10-28 | 2011-10-28 | Adjusting circuit for backlight brightness of LED |
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| CN202434187U true CN202434187U (en) | 2012-09-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011204192197U Expired - Fee Related CN202434187U (en) | 2011-10-28 | 2011-10-28 | Adjusting circuit for backlight brightness of LED |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102855849A (en) * | 2012-09-20 | 2013-01-02 | 青岛海信电器股份有限公司 | Liquid crystal backlight driving current control device |
| CN102982770A (en) * | 2012-11-23 | 2013-03-20 | 四川长虹欣锐科技有限公司 | Flat panel light emitting diode (LED) backlight drive output short circuit protective circuit |
| WO2016061845A1 (en) * | 2014-10-20 | 2016-04-28 | 深圳市华星光电技术有限公司 | Analog dimming conversion circuit and display device |
| US9408260B2 (en) | 2014-10-20 | 2016-08-02 | Shenzhen China Star Optoelectronics Technology Co., Ltd. | Analog dimming conversion circuit and display device |
-
2011
- 2011-10-28 CN CN2011204192197U patent/CN202434187U/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102855849A (en) * | 2012-09-20 | 2013-01-02 | 青岛海信电器股份有限公司 | Liquid crystal backlight driving current control device |
| CN102855849B (en) * | 2012-09-20 | 2015-05-06 | 青岛海信电器股份有限公司 | Liquid crystal backlight driving current control device |
| CN102982770A (en) * | 2012-11-23 | 2013-03-20 | 四川长虹欣锐科技有限公司 | Flat panel light emitting diode (LED) backlight drive output short circuit protective circuit |
| WO2016061845A1 (en) * | 2014-10-20 | 2016-04-28 | 深圳市华星光电技术有限公司 | Analog dimming conversion circuit and display device |
| US9408260B2 (en) | 2014-10-20 | 2016-08-02 | Shenzhen China Star Optoelectronics Technology Co., Ltd. | Analog dimming conversion circuit and display device |
| GB2547356A (en) * | 2014-10-20 | 2017-08-16 | Shenzhen China Star Optoelect | Analog dimming conversion circuit and display device |
| GB2547356B (en) * | 2014-10-20 | 2021-01-13 | Shenzhen China Star Optoelect | Analog dimming conversion circuit and display device |
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| C14 | Grant of patent or utility model | ||
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120912 Termination date: 20151028 |
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| EXPY | Termination of patent right or utility model |