I'm trying to make a battery powered arduino, so I bought a pro mini, that can be powered by 3.3V. I'll be using rechargeable batteries and found that AA Ni-MH are the most efficient / cost-effective / easy-to-use. All of my research made me realize that a voltage upscale is not that easy (if you prove me wrong on this, I'll thank you eternally), so I'll be using 3 of them. That makes a theoretical 3.6V with a range of 3.24V when depleted and 3.96V when fully charged.
I want the voltage output to be constant at about 3.3V, so my best results lead me to this voltage regulator. I understand that it will reduce the voltage to 3.3V and the rest of the input will be wasted as heat, so my 3 battery plan had the least energy waste.
The problem became obvious when the batteries dropped to just 3.8V: the voltage regulator dropped its output to 3.0V.
Now, keeping in mind that the power requirements will differ by the time, since there will be two tiny motors that won't be running constantly, is there any way for me to provide a constant 3.3V from the least amount of batteries and without spending a fortune on the regulator (that is up to 3€, else I just add one more battery)?
Best Answer
Unfortunately an LD33V (real name LD1117V33) is a lowish dropout regulator, not a low dropout regulator. It's advertised as being better than a 7805, which it is, 1v dropout plays 3v, but the 7805 bar is pretty easy to get under. You can get down to 150mV dropout if you look, certainly beat 1v. Go onto CPC, RS or Mouser, and do a parametric search. MIC5205, ADP1752, BU33TD3, the list isn't endless, but goes on and on.