LED strip drains milliamps of current even while off?

Other Hardware LEDs and Multiplexing
1

Hi guys, I'm using some APA102 for a mobile, battery-powered project. I've noticed that just having the strip plugged in drains current even while displaying nothing. It appears linear in number of LEDs attached, to the tune of ~1 milliamp per LED. This is pretty painful on a battery, because if we have ~50 LEDs, that's 50 milliamps of continuous discharge, even while the microcontroller is in sleep mode and the LEDs are all turned "off".

Has anyone experienced this before, or know what to do about it? Right now I'm considering throwing a MOSFET on the positive voltage line to the strip - I tested and found that disconnecting that wire killed the parasitic drain. However, I'd much prefer to not have to use a transistor, as that uses up another output pin from the board, increases code/BOM/assembly complexity, etc.

2

Tossrock:
Has anyone experienced this before, or know what to do about it?

Yes, and it's completely normal. That's because every LED has a chip in it. And chips don't work for free :wink:

So yeah, if you want to have 0 draw when off you should kill the power. High side mosfet sounds right. Don't forget to pull the data pin LOW before you turn off the mosfet. Not only does it draw current when you don't, it can also kill the first led. Also, don't forget the resistor inline with the first led and the Arduino.