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Topic: How is LED power dissipation calculated when multiplexed? (Read 645 times) previous topic - next topic

magagna

Hi,

I've got a 24x16 LED array and I'm switching rows @ 10Khz (0.1ms duty cycle). If I give an LED 100mA @ 2v that's 200mW.

The spec sheet says max dissipation is 60mW but I can't find anything that says if that's an average or a pulse maximum, so am I overdriving these LEDs or am I really just driving them at 12.5mW (200 /16) ?

Thanks
http://en.wiktionary.org/wiki/magagna <-- My last name.  Pretty apt.

retrolefty

Quote
The spec sheet says max dissipation is 60mW but I can't find anything that says if that's an average or a pulse maximum, so am I overdriving these LEDs or am I really just driving them at 12.5mW (200 /16) ?


  It would be at the 12.5mW value. Keep in mind that even when multiplexing the current should be maintained at or below the maximum peak current rating from the datasheet. So in this case you should verify that the datasheet rates the device for 100ma peak current, most do I think.

Lefty

magagna

http://en.wiktionary.org/wiki/magagna <-- My last name.  Pretty apt.

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