I'm an arduino hobbyist since about 4/5 years now, I generally build directly piling shields and modules, but this time, I will need to do my own circuit board, because of space limitation. Since I never had until now to "design" my own circuit at least with that level of "complexity" (and since I do electronics as a hobby for fun and don't work in electronics, it becomes complex really quickly for me ).
The project I'm working on needs to be powered all the time, and power might be going on and off quite frequently, therefore I've been working on some schematics, that would power up the rest of the electronics, while charging a lithium battery, and, if power would go off, it would then use the battery while without main power.
The battery will be a 18650 style lithium battery, so I decided to use a MP73837 chip, for managing the charging of the battery, a LM2940CS-6.0 for main voltage regulation (since I'll have arround 12V input), and a CPC1017N (a solid state relay normally open with MOSFET) for switch power source.
After searching a lot over the net, reading forums and datasheets, I came up with the following schematics :
I think that it might be correct, so I would like some advices arround this schematics.
The "arduino" and related "modules" (in quotes because I'll put an atmega linked directly to the difference needed sensor chips on the board) part will be on the 3.3V side (after the LF33_TO252), It will draw about .5A to 1A in normal, and 2A peak but really short and casual (@3.3V).
So if some good soul comes by this topic and could give some good advice on this, I would be really thankful ^^'.
Thanks a lot in advance,
UPDATE: it seems that the LM2940CS is NOT available in 6V ... so I'll have to use a 5V one (LM2940CS-5.0) but I think the rest still valid.