I am replicating the TP4056 charging circuit on https://www.best-microcontroller-projects.com/tp4056-page2.html and solving the power-sharing problem. The website mentions a Rpull resistor that pulls down the diode but doesn't explain what values to use.

Does anyone have any experience with this? What value of Rpull should be used?

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  • \$\begingroup\$ Can you simulate a good value? Can you do some mental ranging, like would 1 to 100 ohms sound good, or 1k to 100k, or 1 Mohm to 100 Mohm? Then the next question is, does it really matter much which exact value it is, as long as it is not too low or too high? \$\endgroup\$
    – Justme
    Aug 30, 2021 at 19:52
  • \$\begingroup\$ I'd guess that it depends mostly on the reverse-leakage current spec of whatever diode you use for D1. Rpull needs to be low enough that it can sink that amount of current and the Rpull/Q1gate/D1anode net stays low enough to keep Q1 properly turned on. \$\endgroup\$
    – brhans
    Aug 30, 2021 at 19:57

1 Answer 1


Since you are a new contributor: Read Microchips application note AN1149 that is referenced in the link you provided. If you haven't read them before, application notes are like fun datasheets. ;)

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  • \$\begingroup\$ Oh wow thanks @Dejvid_no1! Didn't know these existed. \$\endgroup\$
    – trex98
    Aug 31, 2021 at 18:33

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