I would like to power my Arduino DUE using a 4 cell li-poly battery (volt is higher than the maximum of DUE tolerance). I'm a tenderfoot and has made a LM317 regulation circuit ... My question is how can I still power the DUE together with this regulator in between , even though the LM317 needs a minimum maintaining regulation current of 3.5 mA?
I think I have done all of things according to those datasheets, and there is no short circuit, but the voltage of a fully charged 3 cell li-poly battery will drop very soon, after about only 10 min usage , from 11v to 8v for example...
COULD ANY ONE SHARE YOUR BRILLIANT IDEA?
Any help will be appreciated .
The Due can be powered by a source between 6 and 20 volts; recommended value is between 7 and 12 volts. The 5V regulator on the Due is a switching type rather than a linear. This means that it will not get as hot if the voltage is a little higher than 12V. In addition, the regulator shuts down if it gets too hot.
but what if I must use battery with a LM317? Its not so finger-burning, but the voltage of battery will drop rapidly … Could anywhere be wrong?
You don't need a 317 regulator as long as your battery voltage is less than 20V. The drooping battery voltage does not matter until it goes below 7V. A great advantage of a switching regulator is the high efficiency. For instance, if the Due needs 160 ma and your supply voltage is 12V, the draw on the battery will only be 80 ma or less. The regulator on the Due is an LM2734Y (or LM2736Y). Section 7.3 of the LM2734 data sheet lists the various protections built in. A 317 regulator is linear and would just turn some of your precious battery supply into heat with no gain.
Thank you, it's really help.