CN101197115A - Automatic brightness regulation circuit of display equipment - Google Patents
Automatic brightness regulation circuit of display equipment Download PDFInfo
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- CN101197115A CN101197115A CNA2006102012278A CN200610201227A CN101197115A CN 101197115 A CN101197115 A CN 101197115A CN A2006102012278 A CNA2006102012278 A CN A2006102012278A CN 200610201227 A CN200610201227 A CN 200610201227A CN 101197115 A CN101197115 A CN 101197115A
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Abstract
The invention relates to an displayer illumination automatic adjusting circuit for adjusting the illumination of the displayer automatically, which comprises the following parts: a voltage adjusting circuit with a light source detecting element which detects the illumination of outer environment and outputs a voltage signal changing with the outer environment illumination through the light source detecting element; and a pulse width modulating signal generating circuit which is used for receiving the voltage signal and outputting the pulse width modulating signal changing with the voltage signal to the illumination control circuit of the displayer for controlling the illumination of the displayer. The illumination automatic adjusting circuit of displayer can automatically adjust the illumination of the displayer with the change of the environment illumination.
Description
Technical field
The present invention relates to a kind of circuit of regulating display brightness.
Background technology
Universal day by day along with LCD makes the application of LCD become more and more widely.When using LCD, human eye is responsive to the brightness ratio of display surrounding environment, and especially the sudden change meeting of brightness produces harmful effect to people's vision, and this point is particularly outstanding concerning the notebook computer user.In order to reach the visual effect of the most comfortable, the user need regulate the variation of brightness to conform of display.
Existing LCD brightness regulating circuit is arranged in the LCD and its shell is provided with some adjusting buttons, the user need regulate the brightness of display with the described button of manual manipulation, not very convenient, particularly for the user who uses notebook computer on the road, because ambient brightness constantly changes, adjusting brightness just seems and more bothers.
Summary of the invention
In view of above content, be necessary to provide a kind of automatic brightness regulation circuit of display equipment to regulate the brightness of display automatically.
A kind of automatic brightness regulation circuit of display equipment, be used for regulating automatically the brightness of a display, it comprises that one has the voltage regulator circuit of light source detecing element, and it is by described light source detecing element detecting external environment brightness and export a voltage signal with external environment brightness variation; And a pulse width modulating signal produces circuit, is used to receive described voltage signal and exports a pulse width modulating signal that changes with described voltage signal and give the intednsity circuit of described display to control the brightness of described display.
Compared to prior art, described automatic brightness regulation circuit of display equipment utilizes described light source detecing element detecting external light source, and the external light source signal is converted into a voltage signal, the pulse width modulating signal that more described voltage signal is transformed the described display brightness of a may command is given the intednsity circuit of described display, thereby make described display and regulate brightness automatically with the ambient brightness variation, very convenient.
Description of drawings
The present invention is further illustrated in conjunction with embodiment below with reference to accompanying drawing.
Fig. 1 is the schematic block circuit diagram of the better embodiment of automatic brightness regulation circuit of display equipment of the present invention.
Fig. 2 is the circuit diagram of voltage regulator circuit and pwm signal generation circuit among Fig. 1.
Fig. 3 is the waveform voltage signal figure of integrating circuit output terminal among Fig. 2.
Fig. 4 is the waveform voltage signal figure of comparator circuit output terminal among Fig. 2.
Embodiment
Please common reference Fig. 1 and Fig. 2, automatic brightness regulation circuit of display equipment of the present invention is used for regulating automatically the brightness of a display, its better embodiment comprises a voltage regulator circuit 10 and a PWM (Pulse Width Modulation, pulse-length modulation) signal generating circuit 20.Described pwm signal generation circuit 20 comprises an integrating circuit 22, a comparator circuit 24 and an on-off circuit 26.
Described voltage regulator circuit 10 comprises a light source detecing element (as a photoresistance 11), one first resistance 12, one second resistance 13, one the 3rd resistance 14, one first electric capacity 15 and one first dc power supply terminal Vcc.The described first dc power supply terminal Vcc connects described photoresistance 11 and described first resistance, 12 back ground connection successively, described first electric capacity 15 is connected in parallel with described first resistance 12, and described photoresistance 11 is connected described second resistance 13 and the 3rd resistance 14 back ground connection successively with the node of described first resistance 12.Described photoresistance 11 is located on the housing of described display, and in order to gather the external light source signal and to change self resistance value according to the variation of external light source brightness, promptly when external light source brightened, the resistance value of described photoresistance 11 diminished; When the external light source deepening, it is big that the resistance value of described photoresistance 11 becomes.Other elements all are located on the internal circuit board of described display.
Described integrating circuit 22 comprises one first operational amplifier A 1, one the 4th resistance 222 and one second electric capacity 224, described comparator circuit 24 comprises one second operational amplifier A 2, one the 5th resistance 242, one the 6th resistance 244, one the 3rd electric capacity 246 and one second dc power supply terminal Vdd, and described on-off circuit 26 comprises one the 7th resistance 262, one the 8th resistance 264 and a transistor Q.The negative electrode input end of described first operational amplifier A 1 is connected on the node of described photoresistance 11 and described first resistance 12 by described the 4th resistance 222, described second electric capacity 224 is connected between the negative electrode input end and output terminal of described first operational amplifier A 1, and the anode input end of described first operational amplifier A 1 is connected on the node between described second resistance 13 and the 3rd resistance 14.The output terminal of described first operational amplifier A 1 is connected in the negative electrode input end of described second operational amplifier A 2, the described second dc power supply terminal Vdd connects described the 3rd electric capacity 246 back ground connection, the described second dc power supply terminal Vdd also is connected in the anode input end of described second operational amplifier A 2 by described the 6th resistance 244, the anode input end of described second operational amplifier A 2 is connected in the output terminal of described second operational amplifier A 2 by described the 5th resistance 242, the output terminal of described second operational amplifier A 2 is connected in the base stage of described transistor Q by described the 7th resistance 262, the grounded emitter of described transistor Q, the collector of described transistor Q are connected in the negative electrode input end of described first operational amplifier A 1 by described the 8th resistance 264.The described first dc power supply terminal Vcc and the second dc power supply terminal Vdd can be directly connected on the direct supply of described display interior.
Described pwm signal generation circuit 20 also is located on the internal circuit board of described display, and be connected in the pwm signal input end of inverter in the described display interior intednsity circuit by the output terminal of described second operational amplifier A 2, described inverter can change the variation of its output current according to the change that is input to pwm signal on its pwm signal input end, the variation of the described display brightness of the corresponding control of the change of described inverter output current.
If the resistance value of described photoresistance 11 is R0, node and the resistance value between the ground between described photoresistance 11 and described first resistance 12 are R1, the resistance value of described second resistance 13 is R2, the resistance value of described the 3rd resistance 14 is R3, node voltage between described first resistance 12 and the described photoresistance 11 is Vi, node voltage between described second resistance 13 and the 3rd resistance 14 is Vp, and the DC voltage that the described first dc power supply terminal Vcc is connect is V, and following relational expression is then arranged:
Vi＝V*R1/(R0+R1)；Vp＝Vi*R3/(R2+R3)；
Can derive: Vp=[V*R1/ (R0+R1)] * R3/ (R2+R3)
Here R1, R2, R3, V are definite value, and the resistance value R0 of described photoresistance 11 and the external environment brightness relation of being inversely proportional to, then when external environment brightened, the resistance value R0 value of described photoresistance 11 diminished, and was that the value of Vp becomes big thereby cause described node voltage; When the external environment deepening, it is big that the resistance value R0 value of described photoresistance 11 becomes, and is that the value of Vp diminishes thereby cause described node voltage.
Described integrating circuit 22 produces a triangle wave voltage signal and makes it export a PWM voltage signal for described comparator circuit 24, described on-off circuit 26 is used for described PWM voltage signal is fed back to described integrating circuit 22, and the conducting of controlling described transistor Q by described PWM voltage signal with end, make 224 chargings capable of circulation of described second electric capacity, discharge, thereby make described integrating circuit 22 produce the described triangle wave voltage signal of sustainable generations.
Please continue with reference to figure 3, the oscillogram of the triangle wave voltage signal that produces for described integrating circuit 22, the initial voltage of described triangle wave voltage signal is described node voltage Vp, and from the above: when external environment brightened, it is big that the initial voltage of described triangle wave voltage signal becomes; When the external environment deepening, the initial voltage of described triangle wave voltage signal diminishes.
Please continue with reference to figure 4 oscillogram of the described comparator circuit 24 corresponding PWM voltage signals that produce when equaling the voltage of anode input end of described first operational amplifier A 1 for voltage as described node voltage Vp.Yi Zhi, when the voltage of described node voltage Vp during greater than the voltage of the anode input end of described first operational amplifier A 1, the dutycycle of described PWM voltage signal will be big to strain, otherwise when the voltage of described node voltage Vp during less than the voltage of the anode input end of described first operational amplifier A 1, the dutycycle of described PWM voltage signal diminishes correspondence, the dutycycle and the described node voltage Vp that are described PWM voltage signal are proportional, can release according to aforementioned content: when external environment brightened, it is big that the dutycycle of described PWM voltage signal becomes; When the external environment deepening, the dutycycle of described PWM voltage signal diminishes.
Because the output terminal of described second operational amplifier A 2 is connected in the pwm signal input end of inverter in the described display interior intednsity circuit, the dutycycle that is the output current of described inverter and described PWM voltage signal is proportional, and then the brightness of described display can change with the change of external environment brightness as can be known.Concrete change situation is: when external environment brightened, the resistance value of described photoresistance 11 diminished, and it is big that described node voltage Vp becomes, and is big thereby the dutycycle of described PWM voltage signal becomes, and then makes described inverter output current become big, so described display brightens.Otherwise when the external environment deepening, described display is with deepening.The degree that described display brightness changes can be by selecting the suitable resistance value and the parameter of other each element to regulate to described photoresistance 11.
When described display was worked, by the control of described automatic brightness regulation circuit of display equipment, described display can be regulated automatically along with the variation of external environment brightness, so that the user can adapt to the light of display, thereby has well protected eyes.Described display is generally LCD, also can be LCD TV or liquid crystal DVD player etc.
Claims (10)
1. automatic brightness regulation circuit of display equipment, be used for regulating automatically the brightness of a display, it comprises that one has the voltage regulator circuit of light source detecing element, and it is by described light source detecing element detecting external environment brightness and export a voltage signal with external environment brightness variation; And a pulse width modulating signal produces circuit, is used to receive described voltage signal and exports a pulse width modulating signal that changes with described voltage signal and give the intednsity circuit of described display to control the brightness of described display.
2. automatic brightness regulation circuit of display equipment as claimed in claim 1, it is characterized in that: described voltage regulator circuit also comprises one first resistance, one second resistance, one the 3rd resistance and one first dc power supply terminal, described first dc power supply terminal connects ground connection behind described light source detecing element and described first resistance successively, described light source detecing element and ground connection after the node of described first resistance is connected described second resistance and the 3rd resistance successively.
3. automatic brightness regulation circuit of display equipment as claimed in claim 2 is characterized in that: described first resistance one first electric capacity also in parallel.
4. automatic brightness regulation circuit of display equipment as claimed in claim 1 is characterized in that: described pulse width modulating signal produces circuit and comprises an integrating circuit, is used to receive the voltage signal of described voltage regulator circuit output and produce a triangle wave voltage signal; One comparator circuit is used to receive described triangle wave voltage signal and produces described pulse width modulating signal; And an on-off circuit, be used for described pulse width modulating signal being fed back to described integrating circuit and making it continue to produce described triangle wave voltage signal.
5. automatic brightness regulation circuit of display equipment as claimed in claim 4, it is characterized in that: described integrating circuit comprises one first operational amplifier, one the 4th resistance and one second electric capacity, the anode of described first operational amplifier and negative electrode input end are used to receive the voltage signal of described voltage regulator circuit output, described second electric capacity is connected between the negative electrode input end and output terminal of described first operational amplifier, and the output terminal of described first operational amplifier is connected in the input end of described comparator circuit.
6. automatic brightness regulation circuit of display equipment as claimed in claim 4, it is characterized in that: described comparator circuit comprises one second operational amplifier, one the 5th resistance, one the 6th resistance and one second dc power supply terminal, the negative electrode input end of described second operational amplifier is used to receive the triangle wave voltage signal of described integrating circuit output, the anode input end of described second operational amplifier is connected in the output terminal of described second operational amplifier by described the 5th resistance, described second dc power supply terminal is connected in the anode input end of described second operational amplifier by described the 6th resistance, and the output terminal of described second operational amplifier connects the intednsity circuit of described on-off circuit and described display.
7. automatic brightness regulation circuit of display equipment as claimed in claim 6 is characterized in that: described comparator circuit also comprises one the 3rd electric capacity, and described second dc power supply terminal connects ground connection behind described the 3rd electric capacity.
8. automatic brightness regulation circuit of display equipment as claimed in claim 5, it is characterized in that: described on-off circuit comprises one the 7th resistance, one the 8th resistance and a transistor, the described pulse width modulating signal that described comparator circuit produces exports described transistorized base stage to by described the 7th resistance, described transistorized grounded emitter, described transistorized collector are connected in the negative electrode input end of first operational amplifier of described integrating circuit by described the 8th resistance.
9. automatic brightness regulation circuit of display equipment as claimed in claim 1 is characterized in that: described light source detecing element is a photoresistance.
10. automatic brightness regulation circuit of display equipment as claimed in claim 1 is characterized in that: described display is a LCD.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2006102012278A CN101197115A (en) | 2006-12-07 | 2006-12-07 | Automatic brightness regulation circuit of display equipment |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2006102012278A CN101197115A (en) | 2006-12-07 | 2006-12-07 | Automatic brightness regulation circuit of display equipment |
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| CN101197115A true CN101197115A (en) | 2008-06-11 |
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| CNA2006102012278A Pending CN101197115A (en) | 2006-12-07 | 2006-12-07 | Automatic brightness regulation circuit of display equipment |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102045916A (en) * | 2009-10-15 | 2011-05-04 | 富准精密工业(深圳)有限公司 | Light emitting diode lamp and control circuit thereof |
| CN104361880A (en) * | 2014-11-06 | 2015-02-18 | 河南机电高等专科学校 | Automatic laptop screen dimming system |
| CN104579170A (en) * | 2013-10-25 | 2015-04-29 | 普诚科技股份有限公司 | Relaxation oscillator |
| CN105094356A (en) * | 2014-04-30 | 2015-11-25 | 鸿富锦精密工业(武汉)有限公司 | Computer monitor adjusting system and method |
| CN105352593A (en) * | 2015-11-06 | 2016-02-24 | 南京天易合芯电子有限公司 | Ambient light sensor circuit using high-precision incremental ADC |
| CN105761672A (en) * | 2016-04-25 | 2016-07-13 | 广东欧珀移动通信有限公司 | Method and apparatus for adjusting drive voltage and terminal |
| CN109192180A (en) * | 2018-09-05 | 2019-01-11 | 珠海格力电器股份有限公司 | Display device with automatic brightness adjustment function and control method and electric appliance thereof |
| CN110060628A (en) * | 2019-04-17 | 2019-07-26 | 上海天马微电子有限公司 | Display driving method and device, driving chip and display device |
| CN110120208A (en) * | 2019-04-30 | 2019-08-13 | 努比亚技术有限公司 | A kind of method, wearable device and storage medium that automatic adjustment screen is shown |
| CN110648634A (en) * | 2018-06-26 | 2020-01-03 | 青岛海信医疗设备股份有限公司 | Backlight brightness determining and adjusting method and device, storage medium and electronic equipment |
-
2006
- 2006-12-07 CN CNA2006102012278A patent/CN101197115A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102045916A (en) * | 2009-10-15 | 2011-05-04 | 富准精密工业(深圳)有限公司 | Light emitting diode lamp and control circuit thereof |
| CN104579170A (en) * | 2013-10-25 | 2015-04-29 | 普诚科技股份有限公司 | Relaxation oscillator |
| CN104579170B (en) * | 2013-10-25 | 2017-10-13 | 普诚科技股份有限公司 | relaxation oscillator |
| CN105094356A (en) * | 2014-04-30 | 2015-11-25 | 鸿富锦精密工业(武汉)有限公司 | Computer monitor adjusting system and method |
| CN104361880A (en) * | 2014-11-06 | 2015-02-18 | 河南机电高等专科学校 | Automatic laptop screen dimming system |
| CN105352593A (en) * | 2015-11-06 | 2016-02-24 | 南京天易合芯电子有限公司 | Ambient light sensor circuit using high-precision incremental ADC |
| CN105352593B (en) * | 2015-11-06 | 2018-01-02 | 南京天易合芯电子有限公司 | A kind of circuit of ambient light sensor using high-precision increment type ADC |
| CN105761672A (en) * | 2016-04-25 | 2016-07-13 | 广东欧珀移动通信有限公司 | Method and apparatus for adjusting drive voltage and terminal |
| CN110648634A (en) * | 2018-06-26 | 2020-01-03 | 青岛海信医疗设备股份有限公司 | Backlight brightness determining and adjusting method and device, storage medium and electronic equipment |
| CN109192180A (en) * | 2018-09-05 | 2019-01-11 | 珠海格力电器股份有限公司 | Display device with automatic brightness adjustment function and control method and electric appliance thereof |
| CN110060628A (en) * | 2019-04-17 | 2019-07-26 | 上海天马微电子有限公司 | Display driving method and device, driving chip and display device |
| CN110120208A (en) * | 2019-04-30 | 2019-08-13 | 努比亚技术有限公司 | A kind of method, wearable device and storage medium that automatic adjustment screen is shown |
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Open date: 20080611 |