[Circuit design] Use of single-cell lithium battery

Preface

  Recently I have been studying how to use a single lithium battery to power a 3.3V microcontroller.

Found two better tutorials

• How to convert a single lithium battery to 3.3V? Boost or step down?

• If the lithium battery is connected to the protective board, can it be charged directly with five volts?

Among the LDOs mentioned above, here is a model: ME6209

MP2155 Application Example

Analysis of the principle of lithium battery protection board

question

• After testing, it was found that there are certain problems when using TP4056, probably because it cannot be charged and loaded at the same time.

Design details

Other charging chips:

• PW4054
• link
• link2

How to check battery level

  If it is not a very important occasion, you can wait until the battery is fully discharged, that is, trigger the low-voltage protection function of the protection board, and then start charging. But if it is a very important device, that is, if the power cannot be cut off casually, the battery power needs to be tested.

Refer to this article , it is recommended to use the MAX17055 chip