APA102 flickering

C

cpedw

Senior Member
I have a pretty rainbow program (based on post 30 here) driving APA102s running on a 20X2. It drives a 48 element string well. If I put a second string of 48 elements in parallel, there's a significant amount of flicker - occasionally, odd elements go dark briefly. The flicker occurs at the same time and location in both strings. Rearranging the string to be 96 elements long, and modifying the program to suit, it all works fine again.

Why would the flicker happen? Could it be avoided by some buffering of the clock and/or data lines?
 
Is you power supply able to deliver enough current for the two Strings of LEDs.
I run up to 24 strings of 24 LEDs in parallel but I only drive then at count 40 not the full 255 and they are plenty bright enough for my Christmas display. I use a 10A 5V power supply. Also I use WS2812 LEDS but not with a Picaxe, I use a raspberry pi pico running MMBasic for these.

Bill
 
I'm fairly confident in the power supply. It's rated 3A and the draw is measured at about 0.6A max. Also, the running all the lights in one series string doesn't lead to flicker.
 
Just in case, I tried a different, 5A power supply and yes, it worked fine. Next I used the original power supply but with 1000μF across the rails and it worked fine again. Problem solved , thanks Bill. Incidentally, I am running the LEDs at half power, count 128.
 
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