I want a 3.3v power regulation circuit for esp32 Pico d4 using ams1117 3.3.I will use 18650 batteries for powering. Since esp32 run in 3.3v providing 3.7v will reduce its lifetime.I need a 3.3v power regulator for 3.7v 18650 battery using ams1117 3.3v with charging
Why do you want to use an AMS1117 3.3V, its not suitable for powering a 3.3V device from a single 18650 battery.
Passing the battery current through a regular silicon diode will provide a drop of about 0.6v which is probably sufficient.
iirc the ams1117 has a minimum drop of 1-1.2V. There are regulators with much lower drop-out (and lower maximum input voltage) such as the RT9013. The battery will produce nearly 4.3V when fully charged, dropping to about 3.2V when empty (and that's also when the discharge protection should kick in).
Robin2: Passing the battery current through a regular silicon diode will provide a drop of about 0.6v which is probably sufficient.
maybe but its peak voltage 4.2v
4.2V - 0.6V = 3.6V.
That’s the absolute maximum rating for the ESP32, and with batter voltage dropping quickly in the beginning that shouldn’t be an issue.