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Topic: Glitching TLC5940 (Read 4 times) previous topic - next topic

Nick Gammon

The trick with oscilloscopes is to have a pretty good idea of what "normal" is, then you can spot "abnormal".

Also put aside a few hours to getting the hang of it. Otherwise you might just be measuring line hum and thinking that it is part of your project.

Inevitableavoidance

#51
Apr 05, 2012, 12:34 pm Last Edit: Apr 05, 2012, 12:40 pm by Inevitableavoidance Reason: 1
I re-soldered all the LED's in blocks instead of rows, and hooked up the newly wired breadboards, and everything was fine! No glitching or bugs of whatever..

But then I was trying to hook up the spectrum-shield I have, to make a graphic equalizer, and I accidentally shorted my power supply. Then I replaced all the molten wires, and all the TLC's (just to be sure, they were pretty warm) and hooked everything back up to how it was, and the glitching is back!

I however found that when i tightly grip my 7805, the glitching will be gone. My oscilloscope will arrive somewhere today..

Edit:

Also, before shorting the power supply, I hooked up an arduino to the TLC's without connecting the ground, that's probably what caused the TLC's to become very hot, and that's why I replaced them.

Edit:

The glitching seems to be gone for the moment now.. I moved the board from the ground to against the wall.

Grumpy_Mike

Quote
I however found that when i tightly grip my 7805, the glitching will be gone.

That implies the regulator has not got enough high frequency suppression. Put a 0.01uF across the input and output terminals as close to the regulator as you can get.

Inevitableavoidance

Quote
Put a 0.01uF across the input and output terminals as close to the regulator as you can get.


There are already .1uF caps there, should I replace those or add the .01uF?

James C4S


Quote
Put a 0.01uF across the input and output terminals as close to the regulator as you can get.

There are already .1uF caps there, should I replace those or add the .01uF?

Add.

High frequency noise is filtered out by lower value caps.  Having multiple caps in parallel improves the frequency response of the de-coupling.
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