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I have the Blinkt! Module for my Raspberry Pi (https://shop.pimoroni.com/products/blinkt) which from what I can tell features 8 APA102C LEDs (Datasheet: https://cpldcpu.files.wordpress.com/2014/08/apa-102c-super-led-specifications-2014-en.pdf)

I realised that even when all LEDs are turned off, the module gets to a temperature of around 30°C when connected to the Raspberry Pi 5V line. The powermeter connected to my Raspberry Pi power unit shows an increase of power consumption by 0.4W when the turned of LED strip is connected to the Pi. When I measured the LED strip current with a multimeter, it was something like 42 mA when off and a maximum of 210 mA when all 8 LEDs are turned on with the color white at maximum brightness. The voltage of the 5V line on the Raspberry Pi was 5.351V last time I measured.

Is this much energy consumption normal for APA102 LEDs that are turned off and should I be concerned that this could damage them overtime, when there is a constant current running through them that raises their "off" temperature to 30°C?

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  • I fail to see your problem, unless the laws of physics are being violated and they are somehow less than the 30 when using 5x the power when on. You have what they are a device that uses power when supposedly off, they will last however long they will doing that as designed to do. Since the Pi always draws power itself when supposedly shutdown unless it is removed from it by terminating the connection they will stay in that condition until they die, the both of them. In short disconnect the power to either them or the Pi itself to see no usage of it.
    – user130167
    Mar 3 at 22:08
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So that datasheet is a little slim on the details, so don't blame yourself too much. The APA102C has internal regulators,and an IC that is processing the serial stream at all times even with the LED is commanded into the "off" state. So that will certainly consume some power. The datasheet shows that power consumption is between 0.2W and 1W so presumable the lower end of that is what the power consumption is near the "off" state. With a 5v input voltage that's 40mA which seems a little high on a per-led basis, but gets you in the ball-park.

As for the temperature, the datasheet does call out a max operating temp of 70c. 30c is a very reasonable temp for electronics to be working at. So any extra power you start dissipating in the LED on top of that baseline power will contribute to a temperature rise ontop of 30c. Since you've got plenty of room between 30c and 70c you should be good.

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