CN2838200Y - Boosting white LED drive - Google Patents
Boosting white LED drive Download PDFInfo
- Publication number
- CN2838200Y CN2838200Y CN200520036025.3U CN200520036025U CN2838200Y CN 2838200 Y CN2838200 Y CN 2838200Y CN 200520036025 U CN200520036025 U CN 200520036025U CN 2838200 Y CN2838200 Y CN 2838200Y
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Abstract
The utility model discloses a boosting white LED driver, including a driving IC, an electrical inductance, a voltage stabilizing tube, a first filtering capacitance and a second filtering capacitance; the electrical inductance is arranged between an input voltage pin and a switch pin, and the voltage stabilizing tube is arranged between the switch pin and an output voltage pin. The first filtering capacitance is arranged between the input voltage pin and the ground, and the second filtering capacitance is arranged between the output voltage pin and the ground. The utility model also includes a PWM wave generator, whose output is connected with a stop pin of the driving IC. Owing to the installation of the PWM wave generator, the output PWM wave of the utility model can make output of gentle voltage ripple and surge current through the frequency frame measuring of the PWM intensity control, the soft start and an RC filter, and the gentle voltage ripple and surge current can reduce the short-term change delta ia/ delta t of the current of the electric inductance L and the short-term change delta vc/ delta t of the filtering capacitance C2. Thus the noise is reduced, and subsequently the display effect is improved.
Description
Technical field
The utility model relates to a kind of booster type White LED driver.
Background technology
Since lcd technology is succeeded in developing, the little power consumption of low-voltage, flat structure show because it has, the display message amount is big, be easy to colorize, long-life, unique advantage such as radiationless, pollution-free, now have been widely used in fields such as mobile phone, portable computer, video camera.
And the small sized colour LCD display adopt White LED as backlight be optimal, this is that circuit is simple, characteristics little, that efficient is high, price low and the life-span is long take up space because it has.The forward voltage drop of White LED is than general colored led height, be approximately 3 to 4V, and portable type electronic product for example the cell voltage of PDA, GPS, digital camera, mobile phone of new generation etc. generally be lower than 3.6V, therefore need a boost type power supply drive White LED.But the booster type White LED driver that has is because the existence of peripheral electric capacity and inductance can produce audible noise.
As shown in Figure 1, existing booster type White LED driver, coilloading L ' between the input voltage pin VIN ' of drive IC and switch pin SW ', between switch pin SW ' and output voltage pin OVP ', add voltage-stabiliser tube D1 ', add the first filter capacitor C1 ' and the second filter capacitor C2 ' respectively at input voltage pin VIN ' and output voltage pin OVP '.When add the voltage of a 3V to 5V on input voltage pin VIN ', when adding a high level on shutting down pin SHDN ', booster type White LED driver is just started working, and goes up the voltage that produces a 15V at output voltage pin OVP '.
But inductance L ' on the instantaneous variation Δ Ia/ Δ t of electric current and the instantaneous variation Δ Vc/ Δ t of the voltage of the second filter capacitor C2 ' on the output voltage pin can produce vibration noise.
Summary of the invention
The purpose of this utility model is exactly in order to overcome the above problems, and a kind of booster type White LED driver is provided.
The utility model realizes that the above-mentioned purpose scheme is: a kind of booster type White LED driver comprises drive IC, inductance, voltage-stabiliser tube, first filter capacitor and second filter capacitor; Inductance is added between the input voltage pin and switch pin of drive IC; voltage-stabiliser tube is added between the switch pin and output voltage pin of drive IC; first filter capacitor is between the input voltage pin and ground of drive IC; second filter capacitor is added between the output voltage pin and ground of drive IC; also comprise the PWM wave producer; drive IC comprises that the PWM brightness in sequential series frame of adjusting frequency surveys; soft start and RC filter; the PWM brightness input that frame surveys of adjusting frequency links to each other with the shutdown pin of drive IC; the output of RC filter links to each other with the output voltage pin of drive IC, and the output of PWM wave producer links to each other with the shutdown pin of drive IC.
The PWM wave frequency that described PWM wave producer produces is greater than 2KHZ.
The PWM wave frequency that described PWM wave producer produces is greater than 20KHZ.
The PWM wave amplitude that the PWM wave producer produces is between 0.9V to 5V.
Because the PWM wave producer is set, the PWM ripple of its output is brightness mild voltage ripple and the surge current of output behind frame survey, soft start and the RC filter of adjusting frequency through PWM, voltage ripple that this is mild and surge current can reduce the instantaneous variation Δ Ia/ Δ t of the electric current on the inductance L and the instantaneous variation Δ Vc/ Δ t of the voltage on the second filter capacitor C2, thereby the reduction noise, and then improve display effect.
The PWM wave frequency is during greater than 2KHZ, and voltage ripple and surge current that this PWM ripple produces can reduce the noise that people's ear can be heard effectively.
The PWM wave frequency is during greater than 20KHZ, and voltage ripple and surge current that this PWM ripple produces can be eliminated the noise that people's ear can be heard fully.
The PWM wave amplitude can either activate drive IC between 0.9V to 5V, guarantee that again the drive IC operate as normal can not burnt.
Description of drawings
Also in conjunction with the accompanying drawings the utility model is described in further detail below by specific embodiment.
Fig. 1 is the circuit theory schematic diagram of existing booster type White LED driver.
Fig. 2 is a circuit theory schematic diagram of the present utility model.
Fig. 3 is the circuit theory schematic diagram of drive IC inside.
Embodiment
A kind of booster type White LED driver shown in Fig. 2,3, comprises drive IC, inductance L, voltage-stabiliser tube D1, the first filter capacitor C1, the second filter capacitor C2 and PWM wave producer 1.
Wherein, drive IC comprises PWM brightness in sequential series adjust frequency frame survey, soft start and RC filter, PWM brightness adjust frequency input that frame surveys with shut down pin SHDN and link to each other, the output of RC filter links to each other with output voltage pin OVP; Inductance L is added between the input voltage pin VIN and switch pin SW of drive IC; voltage-stabiliser tube D1 is added between the switch pin SW and output voltage pin OVP of drive IC; the first filter capacitor C1 is added between the input voltage pin VIN and ground of drive IC; the second filter capacitor C2 is added between the output voltage pin OVP and ground of drive IC, and the output of PWM wave producer 1 links to each other with the shutdown pin SHDN of drive IC.
The PWM ripple of PWM wave producer 1 output is brightness mild voltage ripple and the surge current of output behind frame survey, soft start and the RC filter of adjusting frequency through PWM, voltage ripple that this is mild and surge current can reduce the instantaneous variation Δ Ia/ Δ t of the electric current on the inductance L and the instantaneous variation Δ Vc/ Δ t of the voltage on the second filter capacitor C2, thereby reduce noise.
Because the frequency range of people's ear sensitivity is: 2KHZ-16KHZ, so the PWM wave frequency that produces of PWM wave producer 1 is during greater than 2KHZ, voltage ripple and surge current that this PWM ripple produces can reduce audible noise effectively.
And since the frequency range that can hear of people's ear be: 20HZ-20KHZ, so the PWM wave frequency that takes place of PWM wave producer 1 is during greater than 20KHZ, voltage ripple and surge current that this PWM ripple produces can be eliminated audible noise fully.
Can activate drive IC because shut down pin SHDN input 0.9V or higher voltage; the following voltage of input 0.25V can be closed drive IC; may burn drive IC when but input voltage is too high, so the PWM wave amplitude that PWM wave producer 1 produces is between 0.9V to 5V.
Claims (4)
1, a kind of booster type White LED driver comprises drive IC, inductance (L), voltage-stabiliser tube (D1), first filter capacitor (C1) and second filter capacitor (C2); Inductance (L) is added between the input voltage pin (VIN) and switch pin (SW) of drive IC; voltage-stabiliser tube (D1) is added between the switch pin (SW) and output voltage pin (0VP) of drive IC; first filter capacitor (C1) is added between the input voltage pin (VIN) and ground of drive IC; second filter capacitor (C2) is added between the output voltage pin (0VP) and ground of drive IC; it is characterized in that: also comprise PWM wave producer (1); drive IC comprises that the PWM brightness in sequential series frame of adjusting frequency surveys; soft start and RC filter; the PWM brightness input that frame surveys of adjusting frequency links to each other with the shutdown pin (SHDN) of drive IC; the output of RC filter links to each other with the output voltage pin (OVP) of drive IC, and the output of PWM wave producer (1) links to each other with the shutdown pin (SHDN) of drive IC.
2, booster type White LED driver according to claim 1 is characterized in that: the PWM wave frequency that described PWM wave producer (1) produces is greater than 2KHZ.
3, booster type White LED driver according to claim 2 is characterized in that: the PWM wave frequency that described PWM wave producer (1) produces is greater than 20KHZ.
4, according to one of them described booster type White LED driver of claim 1-3, it is characterized in that: the PWM wave amplitude that PWM wave producer (1) produces is between 0.9V to 5V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200520036025.3U CN2838200Y (en) | 2005-11-02 | 2005-11-02 | Boosting white LED drive |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200520036025.3U CN2838200Y (en) | 2005-11-02 | 2005-11-02 | Boosting white LED drive |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2838200Y true CN2838200Y (en) | 2006-11-15 |
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ID=37392691
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200520036025.3U Expired - Lifetime CN2838200Y (en) | 2005-11-02 | 2005-11-02 | Boosting white LED drive |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2838200Y (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100538474C (en) * | 2006-11-28 | 2009-09-09 | 立锜科技股份有限公司 | Backlight Control Circuit |
| CN102281670A (en) * | 2011-05-17 | 2011-12-14 | 深圳市富满电子有限公司南山分公司 | Cycle control white light-emitting diode (WLED) driving chip and driving circuit |
| CN102306482A (en) * | 2007-08-10 | 2012-01-04 | 罗姆股份有限公司 | Driving device |
| CN101308628B (en) * | 2007-05-14 | 2012-07-18 | 奇美电子股份有限公司 | Backlight unit, display device and electronic system |
| CN102695343A (en) * | 2012-06-06 | 2012-09-26 | 矽力杰半导体技术(杭州)有限公司 | LED (Light Emitting Diode) driving circuit |
| CN103295537A (en) * | 2013-05-08 | 2013-09-11 | 深圳市华星光电技术有限公司 | LED backlight driving circuit, backlight module and liquid crystal display device |
| US9257078B2 (en) | 2013-05-08 | 2016-02-09 | Shenzhen China Star Optoelectronics Technology Co., Ltd | LED backlight driving circuit having divider units and method for driving the LED backlight driving circuit |
| CN109308870A (en) * | 2018-08-28 | 2019-02-05 | 出门问问信息科技有限公司 | A kind of anti-flicker circuit and LED display |
-
2005
- 2005-11-02 CN CN200520036025.3U patent/CN2838200Y/en not_active Expired - Lifetime
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100538474C (en) * | 2006-11-28 | 2009-09-09 | 立锜科技股份有限公司 | Backlight Control Circuit |
| CN101308628B (en) * | 2007-05-14 | 2012-07-18 | 奇美电子股份有限公司 | Backlight unit, display device and electronic system |
| CN102306482A (en) * | 2007-08-10 | 2012-01-04 | 罗姆股份有限公司 | Driving device |
| CN101785118B (en) * | 2007-08-10 | 2014-12-31 | 罗姆股份有限公司 | Driving device |
| CN102281670A (en) * | 2011-05-17 | 2011-12-14 | 深圳市富满电子有限公司南山分公司 | Cycle control white light-emitting diode (WLED) driving chip and driving circuit |
| CN102695343A (en) * | 2012-06-06 | 2012-09-26 | 矽力杰半导体技术(杭州)有限公司 | LED (Light Emitting Diode) driving circuit |
| CN103295537A (en) * | 2013-05-08 | 2013-09-11 | 深圳市华星光电技术有限公司 | LED backlight driving circuit, backlight module and liquid crystal display device |
| US9257078B2 (en) | 2013-05-08 | 2016-02-09 | Shenzhen China Star Optoelectronics Technology Co., Ltd | LED backlight driving circuit having divider units and method for driving the LED backlight driving circuit |
| CN109308870A (en) * | 2018-08-28 | 2019-02-05 | 出门问问信息科技有限公司 | A kind of anti-flicker circuit and LED display |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20061115 |
|
| EXPY | Termination of patent right or utility model |