Pwrng a 1064nm Diode/Laser Pointer w/Voltage Regulation

[artis]

@DaveE can you explain what is PIA?
Oh and also is that a LM317 in your hand drawn schematic?

The project takes two 3.7 Nominal Voltage lithium-ion rechargeable batteries in parallel (4.2 charging voltage cut-off and 2.5 discharging voltage cut-off) and will need to regulate the voltage to three different voltages which are 12V, 5V, and 3.3V. What will be the best set up?

I was thinking of two ways. One being boosting the voltage from 3.7V to 12V and then using that 12V to step down to 5V. After that using the 5V and step down the voltage to 3.3V.

The other way is boosting the voltage to 12V and 5V from the 3.7V battery, and use a boost-buck converter for the 3.3V because of the battery range of 4.2 to 2.5V

Or you can use a low power half bridge topology with a small traffo, then you could get every voltage you need by simply making a winding for it and then using a zener or a linear regulator to trim it precisely to the exact specification

Oh and by the way the voltages you are talking about are the exact voltage found in a PC power supply, every PC power supply has 12 volts for fans etc 5 volts and 3.3 for the CPU.
The 3.3 volt line is very stable, why don;t use a PC power supply, they are cheap come it all sorts of power outputs and readily available

 

[DaveE]

can you explain what is PIA?

An inconvenience.

is that a LM317 in your hand drawn schematic?

No. It's an LM1117T, a better version. He doesn't have enough head room for the original. I'm sure there are several other variants that would also work.

 

[DaveE]

you could get every voltage you need

It's not about voltage, it's a current regulator.