(07-27-2017, 03:45 AM)dkryder Wrote: there is a reason that the rock64 power supply units in the store are 3Amp with barrel jacks while the pine64 board power supply are 2Amp with micro usb plug. rock64 uses considerable current compared to many other sbc.
No, not the case dkryder
The reason for the 3A power supply is because that pine64 is standardising on the 3.5x1.35mm (IEC type H) barrel jacks instead of microUSB for two main reasons. The first is that the microUSB connector is only spec'd to handle 1.7 or 1.8A (think it's the latter). So a 2A or more power supply would be stupid in that case. The second it because of crappy microUSB leads with power lines about as thick and as useful as a human hair. Resulting it massive voltage sag when the power is needed, causing instability and data corruption.
So, they have moved the the 3.5x1.35mm connector and a single PSU (with a USB to DC cable as an option also). Which is used by the pinebook, rock64, sopine base board, and the upcoming LTS version of the pine64, plus any other boards they come out with. Why 3A? Because whilst the pine64 and rock64 on their own don't need that, if you have pheripherals pulling power from the rock64/pine64, it obviously needs a bit more. And whilst the pinebook only draws around 1.8A, that just means the power supply isn't being run flat out, so doesn't get seriously hot like a lot of others do.
To give you an idea of actual power requirements of the rock64, here are two quick (and crap quality - I'll re-upload them later in HQ instead of SD) videos of the rock64 booting, and the rock64 running a cpuburn-A53 processor load test. You can see from the USB power meter that it uses under 1A when the CPU is loaded. This is with it running up at 1.3Ghz...