Author：Date：2015-10-30
Why LED Driver is needed in LED lighting?
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Convert AC power into DC, or from one DC level into higher/lower DC.
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Maintain Constant current control of LED.
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Perform various of protection to LED, such as over voltage, over load, and over temperatures shutdown and etc
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Perform dimming function for the LED:
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Front end dimming
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PWM dimming
Typical Topology in LED driver
• Buck (Step Down) –when VIN > VOUT
– Driving a single 1W LED from a 12V supply
• Boost (Step-Up) - when VIN < VOUT
– Driving 6 LEDs in series from a 5Vsupply
•Buck-Boost – When VIN > VOUT and VIN ≤ VOUT
– Driving 4 LEDs from a 12 V car battery
•AC/DC – PFC boost, Flyback, Forward, LLC, etc
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