I've got a power supply that is suposed to provide 5V of DC voltage, I use it for powering an LED Strip (WS2812B) and I've measured the voltage right after turning it on and it's about 7V (for no more than half a second) and then it normalizes to a stable 5,1V.

I wanted to know if this could be a problem, or is this scenario just normal and nothing will happen to my LED Strip

  • 1
    \$\begingroup\$ It's not normal but with some load it may shorten in duration or stop doing this. No load can be a problem for some* designs. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Apr 5 '17 at 22:46

That's called a voltage surge.

As always, the truth is the datasheet. In this case, in the Absolute Maximum Ratings section:

WS2812B Absolute Maximum Ratings section

Apparently, your LED strip can withstand voltage surges of 7V. Although it seems OK, you'll be already on the limit each time a surge happens and that can be dangerous.

So you might want to consider using either:

  1. A better power supply with no surges, or
  2. A transient voltage suppressor (TVS, aka tranZorbs).
  • \$\begingroup\$ The TVS is a viable option for me I guess. Could you please let me know which should I buy? I am searching on google tvs 5v but I get no model of diode or something. And also in order to use it I just need to connect it to the VCC rail of the led strip? Thanks \$\endgroup\$ – Fjallbacka Apr 6 '17 at 0:56
  • \$\begingroup\$ I've done some more research. I need to provide a current of about 9A and the peak voltage surge I've read was 7,7V aprox (as I said it is really fast that I can't even read the number on the voltimeter). Can I use a DO-204AC (DO-15) SAC5.0 on this scenario? Thanks \$\endgroup\$ – Fjallbacka Apr 6 '17 at 11:46

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