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Home > High-brightness LED driver of technology

High-brightness LED driver of technology

 

2008-10-13

 

LED (LED Tester) lighting as a brand-new lighting technology, has been the concern of the world, known as the history of mankind lighting of the third revolution. And a relatively low-voltage halogen lighting the traditional compared with a high-brightness LED interior lights, landscape lighting, automotive lighting has many advantages. High-brightness LED in a smaller power consumption to provide greater brightness (Brightness Meter), with energy saving, environmental protection (Environmental Testing), earthquake resistance, long life and quick access features.

In order to avoid current caused by the change of color bias, pulse (Asymmetric Pulse Tester) width dimming (PWM) is an effective method, PWM-wizard-is just to maintain current unchanged, by controlling the current on-and off-the ratio from 0% ~ 100% of brightness adjustment. For example, to control LED brightness of 33%, in each cycle current 33% open, analog dimming and PWM dimming.

In order to avoid the eye can see the LED's on-and off, PWM dimming the frequency is higher than that of 100 Hz. More than 100 Hz, the eyes will be on-and off-time for the average, only to see the decision by the PWM duty cycle effective brightness. PWM dimming LED are the advantages of being a wizard-has been a constant current, LED color (Colorimeter) will not be the same as the analog dimming will change. PWM dimming can precisely control the brightness of the LED, but also ensure that the LED luminous color. For a certain frequency PWM dimming, dimming the scope depends on the LED current from the shutdown to set the value of time. For example, LED from the current shutdown to setting the time for 20 ms, to 100 Hz of PWM dimming than calculated as follows.

100Hz PWM dimming the minimum duty cycle of 0.2 percent, dimming ratio of 500:1 (0.2% to 100%), if the PWM dimming frequency of 1 kHz, the dimming ratio of 50:1(2% to 100% ).

U.S. market research firm Strategies Unlimited predicts that by 2010, high-brightness LED market will reach 8.3 billion U.S. dollars. Faced with this attractive market, the well-known foreign power management chip makers such as Linear Technology, National Semiconductor, Maxim, Zetex and so launched a series of high-brightness LED Driver. LED driver and the domestic leader Lisun Technology Inc. also launched a series of high-brightness LED driver.

In addition, Lisun Technology Inc. also boost high-brightness LED driver chip PT4108 movements and pressure-type LED driver chip PT4303, the two chips from two AA batteries or a lithium battery-powered drive a 3 W Or 1 W high-brightness LED.

Although LED driver market promising, but there are still some technical challenges, currently facing major challenges: first, to the dimming higher than the efficiency of LED lighting to ensure that high-and low brightness of the same color, while lower The system interference and EMI (EMI Testing); second, with system design, the LED temperature (Temperature Test) for effective detection and control, LED reliable guarantee for the work of his long life and the use of cost advantages.