ESP8266 Community Forum

- Tue Jan 17, 2017 9:10 am #61131 Hello everybody!
I'm searching for this topic on Google since a few days with very poor results so I'm asking here, hoping that this is not a common question.
I am planning to use an ESP12F module to send data via WiFi from a gyroscope/accelerometer, and I need the system to be very light and compact, so I got some 350mAh LiPO battery packs. These output a different voltage (from 4.2 to 2.something) according to their charge level, which is of course not good for the ESP.

Therefore I am looking for a voltage regulator able to step up or down the input voltage while always giving 3.3V as output.
Most of the regulators I found have a ~1V or more droput, so they require at least 4.3V as input which is not good for me..

Does anyone know if there is some component or configuration that can achieve what I am looking for at a decent cost? I will need 5-10 of those, so it would be quite ridiculous to spend 10 times the cost of an ESP

tl;dr: looking for a voltage regulator with stable 3.3V output and from 2 to 5V as input with a suitable output current for an ESP12F module.

Please ask if I was not clear about something, I have decent programming skills but I am an amateur when it comes to electronics.

Thank you!

- Tue Jan 17, 2017 10:43 am #61134 use LiFePO4, mostly "carefree" (not explosive like LiPO) and has acceptable voltage (3.6-3.2V) from 100% to 5% of its capacity ... even charging is no hassle, simply use a current limited 3.6V regulator.

There are several "switched capacity" type regulator chips available., but few as modules.
e.g.: https://www.aliexpress.com/item/5pcs-mi ... 67349.html

regular "coil type" converters usually have very poor efficiency in low power applications.

- Tue Jan 17, 2017 1:04 pm #61146

Hello everybody!
Therefore I am looking for a voltage regulator able to step up or down the input voltage while always giving 3.3V as output.
Most of the regulators I found have a ~1V or more droput, so they require at least 4.3V as input which is not good for me..

I'm currently using a 3.3V supply (actually 3.41V right now, from a raspberry pi) to supply the 5v pin of an RT9013 5V - 3.3V regulator. This is in turn giving me a very stable 3.3V feed (actually 3.28V right now) out of the 3.3V pin of the regulator. I was surprised!

If I read the datasheet right it suggests a typical .25V dropout, with .4V max.

(This isn't something I intend to do long-term - just an effect of some fiddling I'm doing.)

esp8266 otb-iot software - https://github.com/piersfinlayson/otb-iot
esp8266 otb-iot documentation - https://otb-iot.readthedocs.io/
esp8266 related blog - http://www.packom.net/

- Fri Jan 20, 2017 11:46 am #61273 First of all thanks to both of you for answering

@ schufti : I looked for some more info about LiFePO4 batteries, they are too big and heavy for the kind of lightweight system that I am building...
on the other hand the converters are quite interesting, thank you!

@piersfinlayson: I found on the interwebz a RT9013 version (the RICHTEK RT9013-33GB) with fixed 3.3V out and 2~5.5V in, which would be perfect for me if only I could find someone selling them