Maximum current drawn from 3.3 V pin on Spark Core?

That’s most of it, actually.
I am using a Spark Core and I need to power up some leds. I made a PWM driven transistor circuit so that I don’t have to power them up directly with the current drawn from the pins (as far as I understand, they support approx. 40 mA max, so I definitely don’t want to burn them). The energy source for my PWM driven circuit, however, is the 3.3 V pin on the Spark itself, which should be directly connected to the power supply and not go through the most delicate parts of the chip.

  • Am I right about that? Is it safe to use the 3.3 V pin to power up my leds?
  • What is the maximum current that that pin can provide?

Thanks a lot!

These are probably the ones you’re looking for:

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@matteo_monti, the STM32 pins can only sink 20ma and the 3V3 pin can supply a max of 500ma required for both the Core and any user-powered devices. I would not draw more than 150ma from the 3V3 pin. All the info you need is in the Core documentation.

@peekay123, same mistake :stuck_out_tongue: he needed for Core and we gave Photon :smiley:

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