I have a 10A 5v power supply.

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1

I have a 10A 5v power supply. Unlike my other, less portable power supply, it has +V and -V outputs (my reliable one has +V and COM/GND)

Connecting this new power supply up causes my LEDs to flicker. I can sort of see patterns working, but the all flicker wildly across the colors.

I’ve tested just the +V against the input earth, and it’s in the millivolts range.

Connecting the -V to the Earth just causes the bulbs to stay on, but no color changes take place.

To confirm, they work fine against my old supply and I’ve checked this again and again.

Does anyone know how I can get the -V to work like a GND, or just how to get this working?

Thanks

2

I use switch mode psu’s all the time. If yours isn’t working, it’s probably faulty. Your other supplies COM/GND is another way of saying V-

3

How may LEDs are you powering?

4

I bought two, I’ll try the other. It’s 100 LEDs but is 10A.

5

More than enough power. You might find it’s just a faulty cap in the PSU causing a flutter. If it was cheap enough, just sideline it, if its worth it, it will be cheap to fix. Unless you are experienced with AC, I wouldn’t try and fix it, you can hurt yourself with those switch mode jobbies if you aren’t careful.

6

Thanks. Tried the other (a pain to wire up to the mains safely) and it’s exactly the same. Is there a way to clean /even out the DC, so I don’t have to mess about in dangerous AC?

7

Check your voltage - if it is over 5.2v and you are using an MCU with 3.3v outputs (eg teensy 3.x or due) you will need a level shifter (74HCT245) on your data lines.

8

I can swap with another PSU, and it’s fine. Both meter at 5.25. There’s a little pot - I’ll try turning it down for good measure…