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| Help with simple test of CC LED driver current limit? |
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| carl0s:
Hi. I have these nice tiny boost LED constant current drivers. Perfect for lighting panel backlights from small microcontroller projects. As with most of them, there's a feedback resistor to set the current limit. What is an easy way for me to check what this is actually doing without burning up LEDs? Obviously I will connect my ammeter, but, the question is, can I just stick some big resistors in as the load, or will I not see the correct current thing? Will the current that I observe with a resistor load be the same limit that the driver would set for a series of LEDs ? This is the driver chip: http://pdf.dzsc.com/20090603/200903181710291452.pdf The datasheet seems to suggest that a 1R resistor would set it to 100ma. Which makes sense and tallies with a Diodes Inc driver that I have previously used, where 5R resistor = 20mA. However the supplier of the board itself, say it is set to 300ma, yet there's a 1R resistor fitted. I'm inclined to trust the IC datasheet and say that the board is set for 100mA, but I'd like to test it with a suitable load. Thanks :) |
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