CN201673655U - Backlight LED brightness regulating circuit for liquid crystal screen - Google Patents
Backlight LED brightness regulating circuit for liquid crystal screen Download PDFInfo
- Publication number
- CN201673655U CN201673655U CN2010201787990U CN201020178799U CN201673655U CN 201673655 U CN201673655 U CN 201673655U CN 2010201787990 U CN2010201787990 U CN 2010201787990U CN 201020178799 U CN201020178799 U CN 201020178799U CN 201673655 U CN201673655 U CN 201673655U
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- triode
- led
- liquid crystal
- control chip
- regulating circuit
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Abstract
The utility model discloses a backlight LED brightness regulating circuit for a liquid crystal screen, which comprises a triode, an LED and a control chip, wherein PWM can be generated by the control chip; the collector of the triode is connected with a power supply, the base electrode of the triode is divided into two paths after being connected with a second resistor, the signal of the control chip is received by the first path through a first resistor, the second path is grounded through a first capacitor, the emitter of the triode is connected with the anode of the LED, the cathode of the LED is grounded, and the emitter of the triode is grounded through a filter capacitor. The utility model controls the duty ratio of power supply impulse waves by using the control chip to achieve the purposes of controlling power supply current and further controlling the brightness of the LED.
Description
Technical field
The utility model relates to electronic circuit field, particularly a kind of circuit that is used for small size liquid crystal display LED brightness regulation backlight.
Background technology
The LCD liquid crystal display is the passive type display device, and oneself can't be luminous, can only throw light on to display image by the irradiation that adds light source.Present most LCD adopts cold cathode fluorescent tube (CCFL) as back light, but cathode fluorescent tube also has a lot of deficiencies, at first, the colour gamut that cold cathode fluorescent tube can reach is less, common cold cathode fluorescent tube generally is merely able to reach 72% of NTSC colour gamut, and secondly, cold cathode fluorescent tube belongs to pipe dress light source, even for the brightness that makes the screen zones of different, need a large amount of annexes; Contain mercury in the cold cathode fluorescent tube once more, do not meet environmental protection requirement.
Therefore, now replace the back light of cold cathode fluorescent tube with long service life, environment friendly and pollution-free LED gradually as LCD.And the display brightness of display devices such as LED-backlit LCD need be done adaptive adjustment usually, watches to make things convenient for human eye.The method of now general LED brightness regulation is to regulate the supply current of LED, and the mode of regulating supply current generally is that the control circuit that adds special more complicated is regulated, such as regulating power supply pulse wave frequency.
The utility model content
For this reason, the purpose of this utility model is to provide a kind of liquid crystal display LED brightness regulating circuit backlight that is used for, and this circuit is controlled the dutycycle of power supply pulsating wave by control chip, thereby reaches the purpose of control supply current and the further LED of control brightness.
For achieving the above object, the technical solution of the utility model is as follows:
A kind of liquid crystal display LED brightness regulating circuit backlight that is used for is characterized in that, comprises a triode and LED, also comprises the control chip that can produce PWM; The collector of described triode is connected with power supply, the base stage of described triode is divided into two-way after connecting second resistance, first resistance of leading up to receives the signal of described control chip, the second the tunnel by first capacity earth, the emission of triode is the positive pole of LED very, ground is the LED negative pole, and the emitter of triode is also by filtering circuit ground connection.
Further being characterized as described triode is NPN type triode, and described first electric capacity is the tantalum electrochemical capacitor.
Characteristics of the present utility model are: the dutycycle of control power supply pulsating wave, thus the average voltage of control transistor base power supply utilizes the amplification characteristic of triode, thus reach the purpose of control supply current and then control LED brightness.
Advantage of the present utility model is: the control chip of generally controlling the LCD displaying contents, the function that all has the adjustable pulsating wave of output duty cycle, so can in the control displaying contents, utilize the vacant function of control chip to carry out the adjusting of LED brightness, save the current regulating circuit that much adds.
Description of drawings
Fig. 1 is a circuit structure diagram of the present utility model.
Embodiment
For technological means, creation characteristic that the utility model is realized, reach purpose and effect is easy to understand, below in conjunction with concrete diagram, further set forth the utility model.
As shown in Figure 1, comprise a triode Q1, also comprise the control chip 1 that can produce PWM; The collector of described triode Q1 is connected with power supply VCC, the base stage of triode Q1 is divided into two-way after connecting second resistance R 2, first resistance R 1 of leading up to receives the pwm signal of described control chip 1, the second the tunnel by first capacitor C, 1 ground connection, the emission of triode Q1 is the positive pole of LED very, ground is the LED negative pole, and the emitter of triode Q1 is also by filtering circuit 2 ground connection.
Principle of work of the present utility model is as follows:
Pwm pulse ripple from an EDM Generator of Adjustable Duty Ratio of control chip 1 output, under the effect of capacitor C 1, this pulsating wave is shaped as a height and changes adjustable level, and then the control voltage of control triode Q1 base stage, again by its enlarging function, the supply current of control LED lamp feeder ear (+) and (-), thus reach the purpose of controlling LED brightness.Because the pwm pulse wave frequency is certain, can realize the adjusting of its dutycycle by software.
Triode Q1 in the utility model is a NPN type triode, and first capacitor C 1 is for there being the tantalum electrochemical capacitor of polarity.
More than show and described ultimate principle of the present utility model and principal character and advantage of the present utility model.The technician of the industry should understand; the utility model is not restricted to the described embodiments; that describes in the foregoing description and the instructions just illustrates principle of the present utility model; under the prerequisite that does not break away from the utility model spirit and scope; the utility model also has various changes and modifications; these changes and improvements all fall in claimed the utility model scope, and the claimed scope of the utility model is defined by appending claims and equivalent thereof.
Claims (3)
1. be used for liquid crystal display LED brightness regulating circuit backlight, it is characterized in that, comprise a triode and LED, also comprise the control chip that can produce PWM; The collector of described triode is connected with power supply, the base stage of described triode is divided into two-way after connecting second resistance, first resistance of leading up to receives the signal of described control chip, the second the tunnel by first capacity earth, the emitter of described triode connects the positive pole of LED, the LED minus earth, the emitter of triode is by filtering circuit ground connection.
2. the liquid crystal display LED brightness regulating circuit backlight that is used for according to claim 1 is characterized in that described triode is a NPN type triode.
3. the liquid crystal display LED brightness regulating circuit backlight that is used for according to claim 1 is characterized in that described first electric capacity is the tantalum electrochemical capacitor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010201787990U CN201673655U (en) | 2010-04-28 | 2010-04-28 | Backlight LED brightness regulating circuit for liquid crystal screen |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010201787990U CN201673655U (en) | 2010-04-28 | 2010-04-28 | Backlight LED brightness regulating circuit for liquid crystal screen |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201673655U true CN201673655U (en) | 2010-12-15 |
Family
ID=43331064
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010201787990U Expired - Fee Related CN201673655U (en) | 2010-04-28 | 2010-04-28 | Backlight LED brightness regulating circuit for liquid crystal screen |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201673655U (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102280088A (en) * | 2011-07-26 | 2011-12-14 | 深圳市华星光电技术有限公司 | Light-emitting diode (LED) dimming method and LED dimming system |
| CN102306485A (en) * | 2011-09-06 | 2012-01-04 | 深圳市华星光电技术有限公司 | Light emitting diode (LED) driving circuit, liquid crystal display device and LED driving method |
| CN102842279A (en) * | 2012-08-17 | 2012-12-26 | 上海华兴数字科技有限公司 | Display screen and backlight drive method thereof |
| US8686661B2 (en) | 2011-07-26 | 2014-04-01 | Shenzhen China Star Optoelectronics Technology Co., Ltd. | LED dimming method and LED dimming system |
| CN106332421A (en) * | 2016-09-05 | 2017-01-11 | 深圳市科陆电子科技股份有限公司 | Method and system for controlling electric energy meter backlight |
| CN108490716A (en) * | 2018-03-21 | 2018-09-04 | 上海艾为电子技术股份有限公司 | A kind of screen light filling circuit and electronic equipment |
| CN114267305A (en) * | 2021-12-31 | 2022-04-01 | 广东美的厨房电器制造有限公司 | Integrated control chip and electronic device |
-
2010
- 2010-04-28 CN CN2010201787990U patent/CN201673655U/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102280088A (en) * | 2011-07-26 | 2011-12-14 | 深圳市华星光电技术有限公司 | Light-emitting diode (LED) dimming method and LED dimming system |
| US8686661B2 (en) | 2011-07-26 | 2014-04-01 | Shenzhen China Star Optoelectronics Technology Co., Ltd. | LED dimming method and LED dimming system |
| CN102306485A (en) * | 2011-09-06 | 2012-01-04 | 深圳市华星光电技术有限公司 | Light emitting diode (LED) driving circuit, liquid crystal display device and LED driving method |
| CN102842279A (en) * | 2012-08-17 | 2012-12-26 | 上海华兴数字科技有限公司 | Display screen and backlight drive method thereof |
| CN106332421A (en) * | 2016-09-05 | 2017-01-11 | 深圳市科陆电子科技股份有限公司 | Method and system for controlling electric energy meter backlight |
| CN108490716A (en) * | 2018-03-21 | 2018-09-04 | 上海艾为电子技术股份有限公司 | A kind of screen light filling circuit and electronic equipment |
| CN114267305A (en) * | 2021-12-31 | 2022-04-01 | 广东美的厨房电器制造有限公司 | Integrated control chip and electronic device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20101215 Termination date: 20190428 |