Volt-ampere characteristics of LED

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To choose a good LED driver design, you must first understand the electrical characteristics of the LED itself.

As shown in the figure below, the volt-ampere characteristic curve of the LED with a rated current of 20 mA and a forward voltage of 3.3 V; it can be seen that the LED current has a large variation with voltage. Since the LED current directly determines the output of the luminance, it is necessary to use a driving chip whose control current is constant, and the forward conduction voltage is determined by the current.

Take the LED constant current control chip 029967 of the US company 02MICro, which is the leading company in the field of CCFL fnverter control chip and LED driver chip, as an example, design a liquid crystal TV LED driver solution for 32" LEO backlight. 32" LED backlight LCD The TV uses a 6-channel 120mA white LED with 25 LEDs in series for a total of 150 LEDs.