Author Topic: Help with simple test of CC LED driver current limit?  (Read 805 times)

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Offline carl0sTopic starter

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Help with simple test of CC LED driver current limit?
« on: September 12, 2019, 11:15:00 am »
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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Carl
 


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