Can PICs Drive White LEDs?

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- 9th August 2004, 15:53
RossW

Can PICs Drive White LEDs?

Just wondering whether anyone knows if PICs can sink enough current to drive a 5mm white LED. These take higher voltages than regular LEDs (around 4.5V, I think) and need more current, too. If they can't, I guess I'll have to hook up an NPN transistor ...

Ross
- 9th August 2004, 16:33
Dwayne

hello RossW

Rossw>>Just wondering whether anyone knows if PICs can sink enough current to drive a 5mm white LED. These take higher voltages than regular LEDs (around 4.5V, I think) and need more current, too. If they can't, I guess I'll have to hook up an NPN transistor ...<<

Yes.. they can drive up to 20mill per pin. they run 5 volts 20mills. I have driven Whites

Dwayne
- 9th August 2004, 18:39
RossW

Thanks Dwayne!
- 11th August 2004, 15:46
actionplus

Bright white LED

I am try to get a Super Bright White Led.
I have tried some from lumex.com. Not bright enough.

Also, will just using the regular High PORTA.1 and Low PORTA.1 do it get to flash the Bright LED's?Trying to build a miniature stobe light(Navigation lights) for my scale model.
- 11th August 2004, 16:28
RossW

I'm using some super bright white LEDs from a local supplier in my test environment, and the HIGH/LOW commands work fine (As will PORTB.0 = 1, for example). I'm not sure about using the super brights in my applications, however, as I'm concerned about the amount of current they draw vs. regular LEDs. You could always hook it up to a PNP transistor, I suppose.
- 11th August 2004, 16:50
CocaColaKid

The TOGGLE command will achieve the same result as well.
- 11th August 2004, 20:47
Dwayne

Hello Ross,

Ross>>I'm using some super bright white LEDs from a local supplier in my test environment, and the HIGH/LOW commands work fine (As will PORTB.0 = 1, for example). I'm not sure about using the super brights in my applications, however, as I'm concerned about the amount of current they draw vs. regular LEDs. You could always hook it up to a PNP transistor, I suppose.<<

I do not know the current that your LED's are drawing. I used the 648 and 675... I seem to remember both are allowed 20 mils per pin, and the 675 had a total current limit (for the whole chip) of something like 120mils. That equated to about 20 mils per pin. Stick a amp meter in there, and measure the mils of your LED. then you have a good idea what you are drawing.

Dwayne