LEDS Connected to GPIO

Question

How many LEDS can be connected and ON at once to the RPI GPIO without burning out the system?

The question may be a duplicate, **BUT** the answers are **WRONG**. They may have been correct for the Model B, but not for B+ or later. — Milliways, Dec 12 '16 at 23:52

score 2 · Accepted Answer · edited Apr 13 '17 at 12:56

2

There is no documented limit. Each pin can supply up to 16mA, I would suggest limiting total current to 200mA (this is just an educated guess). The limit for older Pi (any without the 40 pin header) is total 50 mA. See Raspberry Pi Power Limitations

If you need to switch more current use MOSFETS or transistors.

edited Apr 13 '17 at 12:56

Community

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answered Dec 12 '16 at 00:55

Milliways

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According to [this page](https://www.raspberrypi.org/documentation/hardware/raspberrypi/bcm2836/README.md) RPi2 chip is identical to RPi zero in most aspects, so I'd stick to 50mA limit. – Dmitry Grigoryev Dec 12 '16 at 11:05
@DmitryGrigoryev This has nothing to do with the chip. The earlier models had a linear regulator on board (which imposed the limit), the newer models have a switch mode regulator. I don't have a Zero, and AFAIKthe circuitry for this is not published. As per the link above, you can draw ~800mA from 5V, which I have tested on B+, Pi2, Pi3. – Milliways Dec 12 '16 at 23:48
@Milliways Pardon me but I think it has everything to do with the SoC as it is GPIO pins and the internal circuitry that sets the limits here - and I would be very surprised if that has changed much between the different Broadcomm devices that form the heart of a RPi. As an Electrical & Electronics Engineer I'd urge RPi users to limit the loading to that 16mA max (I vaguely recall reading somewhere that it might be adjustable in 1 or 2 mA steps up to that limit - possibly from [this](http://www.thebox.myzen.co.uk/Raspberry/Understanding_Outputs.html) article that the linked to Q&A refers to). – SlySven Dec 15 '16 at 02:35
@SlySven I was referring to the 50mA limit, which is widely quoted. This was because the linear regulator was designed to deliver 50mA (as was explained by Gert van Loo who outlined the design parameters) NOT because of any limit of the SOC. He also explained the [drive](http://www.thebox.myzen.co.uk/Raspberry/Understanding_Outputs.html) and also explained that this this was NOT a current limit. Gert's original document is available, but appears to be behind a paywall. – Milliways Dec 15 '16 at 05:47

LEDS Connected to GPIO

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