How much current should a basic cobra +4.3" screen pull?
Mine hover’s around 400mA is this normal?
This is using a regulated external 5v supply…
Cheers Ian
Yes that is normal. The LCD back light is the reason.
FEZ Cobra itself cosume 180mA to 220mA
[url]http://www.tinyclr.com/compare/[/url]
I don’t mind that sort of consumption but Chris and Brett both say they can run the cobra+ LCD with USB, only they are supposed to be good for 500mA, but my 5v from the USB is dropping past 4.6v…
I think my USB port is very weak
Cheers Ian
The USB spec says that the port can be as low as 4.5V I think so that is within the specifications.
I got curious my usb ports on the asus are pushing 5.6 volts at 800ma. On my touchbook 4.7 volts 400ma. Holy divergence batman but i would guess thats all in spec.
I suppose you are measuring the voltage at FEZ Cobra 5V.
It is dropping because there is a protection Schottky diode in serial with the the power source. the forward voltage for this diode is about 360mV