Voltage Regulators 5 to 3.3v and 3.7v to 5v

Hi all!

I am developing a project which needs to be powered by a 3.7v battery to power 5v ATmega328p-au, as well as 5v to power a 3.3v wifi module. I know this can be achieved with voltage regulators. Can you guys suggest a few voltage regulators to use as well as its schematics?

Also, I would also want to integrate a 3.7v battery charger circuit? Could you also please suggest some circuit to achieve this?

Thanks in advance!

see arduino UNO r3 schematic

3.7V Lipo charger

3.7V Lipo charger circuit

3.7V Lipo charger circuit

Lipo charger post

DIY Lipo charger

fully charged voltage for 1S is 4.2V, not 3.7V.

[ You cannot increase voltage with a voltage regulator - you mean a boost-converter (a kind of DC-DC converter) ]

I think you only need 3.3V? The ATmega328 will run at 3.3V (officially upto about 10MHz, in
practice you can get away with 16MHz at room temperature, but its not guaranteed). If you
use 3.3V throughout you don't need to think about level shifting and you don't need a 5V->3.3V

These days there are probably chips that will regulate 3.7V down to 3.3V and also provide LiPo
charging and protection. Look around.

Take a look at this, for example. It's not cheap, but there are probably other alternatives as well, and then again, if you look at it, you get a charger ànd two voltage regulators ...

Anyway, you'll always need some kind of buck/boost converter or SEPIC (regulators that can have their input higher or lower than their output). The nominal voltage of a Li-Ion is 3.7 volts, but a fully charged one is ~4.2V (which is higher than your target voltage) and most devices turn off at 3.2V or even 3V (which is lower than your target voltage). And as for all voltages in between: even the best LDO (Low DropOut) voltage regulators will struggle to get a stable 3.3V out of 3.7V (or thereabout).

In the link I showed you, they use a boost converter to get the battery voltage to 5V, and then they use a linear voltage regulator to get that 5V down to 3.3V again. (Once you've noticed that, the current ratings seem a bit suspicious though...)

you can use voltage step up module to convert 3.7v-5v,and u can make this simple circuit(at the link) to regulate 5v - 3.3v.