1
\$\begingroup\$

I want to power my ESP32-WROOM-32E module with an 3.7V Li-Po battery. To reduce the voltage to 3.3V I'd like to use LM1117S-3.3 LDO. As far as I know, the most ESP32 developing boards use AM1117 regulator. Is there any differences between AM1117 and LM1117? Is it possible to use LM1117?

\$\endgroup\$
3
  • 3
    \$\begingroup\$ It's not possible to use either of them due to their >= 1 V dropout voltage, it is more than 3.7 - 3.3. \$\endgroup\$
    – MiNiMe
    Sep 18, 2023 at 13:29
  • \$\begingroup\$ You probably mean AMS1117. Details like that are rather important many times. In this case, the answer is 'no' in both cases. They're not really LDOs, more like medium dropout regulators. \$\endgroup\$ Sep 18, 2023 at 14:11
  • \$\begingroup\$ The LM1117 is generally going to be much more reliable than the AMS1117; the latter is a cost-reduced knockoff known for having issues (though I can't recall exactly what issues right now. Something with oscillation?). \$\endgroup\$
    – Hearth
    Sep 18, 2023 at 15:00

1 Answer 1

3
\$\begingroup\$

enter image description here

From: https://www.ti.com/lit/ds/symlink/lm1117.pdf

To generate 3.3V you must provide a battery that is at least 1.3V higher, so this will work as long as your battery is 4.6V or higher. A 3.7V battery will not work.

Depending on how much you care about battery life, a buck-boost converter might make more sense than a linear regulator. It will waste less power and allow you to run the battery to a lower voltage before dropping out.

\$\endgroup\$
3
  • \$\begingroup\$ Will one of this buck-boost converters work. Which is the best to use in my case? \$\endgroup\$ Sep 19, 2023 at 10:06
  • \$\begingroup\$ @AntonTsvayer Yes those look like reasonable choices. I would double check that they can safely handle a dead battery without discharging it below 3v, but otherwise should do what you want. \$\endgroup\$ Sep 19, 2023 at 12:45
  • \$\begingroup\$ Thanks for the answer. For the battery charging management I will use another circuit. \$\endgroup\$ Sep 19, 2023 at 14:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.