kkyip Posted March 31, 2005 Report Share Posted March 31, 2005 Hi guys out there,My name is yip, jus registered in this forum.I was wondering how come we need a LED driver to drive the LEDs, cant we jus do it with simple circuitry? Pls enlighten me, thank you very much Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted March 31, 2005 Report Share Posted March 31, 2005 V is the supply voltage.Vf is the LED forward voltage drop found on the datasheet.I is the forard current - it must be high enough to give reasonable light output but bellow the maximum value listed on the datasheet.In this example:I = 10.4mAVf = 1.9VV = 9VNow you can check that I've used the correct resistor if you want. Quote Link to comment Share on other sites More sharing options...
japroach Posted April 2, 2005 Report Share Posted April 2, 2005 V is the supply voltage.Vf is the LED forward voltage drop found on the datasheet.I is the forard current - it must be high enough to give reasonable light output but bellow the maximum value listed on the datasheet.I dont think thats what hes asking. What hes saying is why use a LED driver chip.Main reason is to have constant current output to a bunch of LEDs.Most of it explained here:http://www.siliconchip.com.au/cms/A_100966/article.html Quote Link to comment Share on other sites More sharing options...
audioguru Posted April 2, 2005 Report Share Posted April 2, 2005 You can see and download the entire article for free if you enter in a Google search, Silicon Chip Online-white LED driver. Quote Link to comment Share on other sites More sharing options...
MP Posted April 2, 2005 Report Share Posted April 2, 2005 kkyip,Welcome to the forum. To answer your original question: YES, you can use discrete components instead of a driver chip. The purpose of a driver chip is so that you save space and money when building the circuit.MP Quote Link to comment Share on other sites More sharing options...
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