hi,
i have already completed a mainboard - 80C52 mcu, 4 x smartcard interface, mifare interface, serial interface. the board is powered by 7V-20V, as it has a DC-DC regulator on board (both for 5V & 3V3 - peripherals & MCU).
Using adjustable power supply to feed the board, it shows a constant current used by the board, around 260mA (7V-12V) - so I believe it wont be possible to reduce to 4mA - unless I turn OFF all peripherals & put everything into SLEEP mode - but have not try it yet..
btw, let say thermal printer will be using around 1.5A during printing & cutting, which supercap would be sufficient to support its operation?
thanks for any help.