Just received my Pibrella through the post. However I can’t find any details on your site or on Cyntech’s of the technical specifications of the board?
When you say the following:
Can drive bigger loads than the Pi GPIO can handle (motors, relays, solenoids, etc.)
4 high-power outputs
Then you need to follow this up with details! Also - can I drive both the RPi and the Pibrella from just the Pibrella USB power socket, or are they both needed (especially in the case of larger loads)?
As Jon says, it’s 500mA per channel, but note that it’s also 500mA for the whole chip! So one channel at 500mA, or 5 at 100mA, etc.
It’s also more dependant on the PSU you use too - make sure it can handle it - and if using a Model B, then you only have some 200mA spare via the GPIO connector, so use a PSU plugged directly into the Pibrella for heavier loads. (And yes,the Pibrella will power the Pi via the GPIO connector, so only one PSU needed - just make sure it’s got enough capacity. One of the Pimoroni 2 amp ones would be perfect.
Just a follow-up - looks like the device on the Pibrella is a higher power variant, so > 500mA in total ought to be fine…
Just make sure the power supply can handle it if you go that high! Small 5v relays ought to be under 100mA though, just be aware of your total current draw.