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I wonder what's wrong with my circuit. Voltage between VIN and GND is 0.5V instead supposed 3.3V.

Is there design issue? Assembly was maded by JLCPCB

VIN voltage: stable 3.3V from PSU (VIN - B_GND) (testing purposes) VIN: Battery plus pin B_GND: Battery ground pin GND: Circuit ground

Schema: enter image description here

PCB: enter image description here

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    \$\begingroup\$ "Voltage between VIN and GND is 0.5V" and "VIN voltage: stable 3.3V from PSU (testing purposes)" is contradictory. Which is it? \$\endgroup\$
    – winny
    Nov 5 '20 at 15:26
  • \$\begingroup\$ @winny thanks for point! Edited. Output pins of PSU are VIN and B_GND. \$\endgroup\$
    – oflfo2
    Nov 5 '20 at 15:35
  • \$\begingroup\$ How are GND and B_GND connected? Your OD signal will have no say since G1 is referenced to B_GND. I suspect you have built a source follower. Can you draw your Q2 as two MOSFETs instead? What are you trying to accomplish by separating the grounds? \$\endgroup\$
    – winny
    Nov 5 '20 at 15:52
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    \$\begingroup\$ Most battery protection ICs disconnect ground instead of power for some reason. See BQxxxxx series from TI and the DW01a used here that is super popular. In this instance, I don't think OP has a choice as to whether to switch power or ground without changing IC. \$\endgroup\$
    – crossroad
    Nov 5 '20 at 16:27
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    \$\begingroup\$ @winny I guess like said Justme. If I merge B_GND to GND then red layer is merged aswell and battery will be connected. Perhaps its just editor issue that forces me to name it something else than "GND" (using Easyeda) \$\endgroup\$
    – oflfo2
    Nov 5 '20 at 16:54
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Trick to enable circuit based on NOTE inside different datasheet page 8/14 second red note:

Note: When a battery is connected to DW01-G for the first time, it may not enter the normal condition (dischargeable may not be enabled). In this case, short the CS and VSS pins or connect to a charger to restore to the normal condition

This trick enables circuit to work properly. However it's disappointing you have to short it every time battery is plugged-in.

I wonder how to avoid shorting VSS x CS every time I plug battery? Important note: Circuit is not charging battery! DW01 is used as overdischarge protection.

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