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(Easy eda's personal project image)

I'm trying to create this battery charger circuit,and I have a doubt whit this TP4056 with protection circuit: what happens if I short the bat ground whit the com ground (out-)? The load would have the battery voltage plus the TP4056 voltage so it would be overvoltage? Is the out- separated from bat- in the original circuit for this reason, to make a switch between TP4056 voltage when battery is low and battery voltage when battery charge is full?

toolic
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elettronicamp
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  • If you short OUT- to B- you may as well leave out the DW01 and FS8205 because you're bypassing them and your battery will have no protection. – brhans Sep 28 '23 at 18:30

1 Answers1

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No, you shouldn't connect both negative outputs together. Look at the same schematic from this site :

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OUT+ and B+ are connected together, but the battery protection IC (DW01A) cuts the negative side (B-) with the two mosfets below when the protection conditions are met.

But it cuts only B- isolating the battery. If you connect OUT- with B- you are bypassing the protection.

Gos
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  • thanks man, and should not the drain of the mosfets be connected with somethings? why are they floating? i can’t figure it out the flux of the circuit. – elettronicamp Sep 29 '23 at 18:42
  • They are not floating, they are connected together. They form a rail. As they are connected in the opposite directions, one blocks the current in case of overcharging and the other one blocks in case of over-discharging. So, when the current flows to the battery (charging) and when the current flows from the battery (discharging). – Gos Oct 01 '23 at 07:16