The LEGO EV3 Hardware developer kit says that the fourth pin of input or output port provides a voltage of 5 volts but doesn't give the the maximum current that can be drawn from the pin.
What is the max current that can be drained from the VCC pin (pin 4 at 5V)?
As seen in the schematics, pin 4 of all of the input and output ports plus the 5V on the USB host port is connected to VCC5V/VCC5VIGEN, which is supplied by U23 (the analog/digital converter is also connected to this, but current draw for that is negligible). U23 is a TPS2041BDBVR which limits the current to 1A and has a continuous current of 500mA.
So all ports and USB need to be considered at the same time and must not exceed 500mA on average or 1A peak.
