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Currently I have a 18650 battery charge and discharge circuit in my Board design as a "Emergency fall-over power. And I have some problems with it.

enter image description here

First problem I see is that while the battery is charging my 5v rail will raise with the battery, instead of keeping it at a constant 5v. Next it seems that if i touch the PCB near the R4 resistor, the charging led will flicker.

Is there a better alternative to the dw01a combo with the tp4056?

Id basically like a constant 5v source reguardless if their is power coming into the board, and a way to tell if the battery is charged/ if the power is plugged in.

Currently the circuit this powers draws somewhere in the neighborhood of 750ma at peak.

And may have an input voltage though a regulator of 4.9 <-> 8.2v

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  • \$\begingroup\$ Why are you connecting a 3.7V battery directly to +5V? \$\endgroup\$ – EE_socal Apr 6 '18 at 0:45
  • \$\begingroup\$ Its what it showed in the datasheet example. \$\endgroup\$ – Steven Venham Apr 6 '18 at 23:07
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    \$\begingroup\$ @StevenVenham What datasheet? You did not include link in your question. Datasheet I have does NOT show battery connected to 5V rail. \$\endgroup\$ – Chupacabras Oct 1 '18 at 9:43
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Firstly, your capacitor C1 should be connected directly to the DW01A Vcc pin, not the battery +ve. It is designed (together with R2) to minimise any ripple from the charging PSU. The output voltage you get will only ever be the battery voltage so whatever that is, that is what you will get. If you want a constant 5 v then you need a boost DC to DC on your board. That way, as your battery voltage drops, you will still get your 5v output. Hope this helps and good luck.

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Your schematic is wrong. Battery is not supposed to be directly connected to 5V rail.
This is schematic from datasheet:
enter image description here

As you can see pin 5 is connected to battery+, 5V rail is connected to R1.

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