Max Amp Input for V3

Hey guys I always run 12V lights and power supplys for my installs and I use a 12V-5V converter for the PB.

I made the mistake of ordering a different DC converter this time than I usually use. I thought it was identical but didn’t realize till I hooked it up that the output Amps is 5A max on these ones and the ones I usually use are 3A max. Apparently this is a problem as none of the new ones are working with my V3s.

I am in a time crunch now after waiting for these converters to ship so is there any workaround for me to be able to use these? I tried using the micro USB on them as well as backfeeding the buck into the 5V and GND screw terminals but nothing worked.

Hi @PB43VER,
The current rating shouldn’t be a problem, but it could be caused by a poor transient response, to use the technical term. That is, how quickly the converter can respond to a fast change in current draw, typically on the sub-millisecond level. For modules, especially if you got a random one from Amazon or something, it can be hard to get that detailed spec (often given as a chart in a data sheet).

You’ll need a converter with at least 600mA (0.6A) of current capability but there’s no upper limit. A converter with 100A of output capability should work as long as it has a good transient response.

The mini-buck converters that I sell are designed using a converter with a very good transient response.

In any event, you might be able to work around the problem by adding a large capacitor to the 5V power (between 5V and GND), which will provide energy while the converter is slow to respond. You will want a fairly large one, 470-1000uF, and a relatively low ESR, and a voltage rating not less than 10V. These can be pretty bulky compared to the other components.

I should add that a capacitor on the input side of the converter can also help, especially if the power supply is far away or overburdened.

Very much appreciated the quick response. Luckily I found a little electronics store locally that I didn’t know about that had a bunch of other bucks and we got one to work for us.

I’ve never actually bought the output expander but that would eliminate the need for a separate buck correct?

The Pro Expander can be ordered in a 12V version that includes a built-in 12V-to-5V-for-Pixelblaze buck converter.

The compact output expander doesn’t. I’ve used it with 12 V LEDs but then I use a separate buck converter to power the Pixelblaze and the expander’s logic at 5V; I then only use the GND and DAT pins on each channel’s outputs.