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DW01-G Battery Protection IC Issues

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AlfroJang80:
Hi,

I recently got one of my PCBs back from JLCPCB which has a 3.3V microcontroller, a 5V step-up converter (for some sensors) and a 3.3V regulator. It's designed to be operated via a 3.7V < 3000mAh battery LiPo pouch cell. There is no charging circuitry on board.

This is the first time I've made a battery circuit. All parts are from lcsc.com.

ISSUE: On plugging in battery, 3.3V rail doesn't start up.  In this problematic state, OD of the DW01-G is at -3.617V and increasing by 1mV every second almost (becoming more positive). OC at 0.247V constant. (Battery at 3.88V). 3.3V rail at 0V.

What I have noticed:
If I short OD and CS of the DW01+G circuit - everything works - 5V and 3.3V rails both come online. But I have to do this everytime battery is plugged in.
I also noticed that once the circuit is in a good state with stable rails, if I remove the battery and plug it back in again, the 3.3V rail shows approx. 580mV failing rapidly.

I have tried replacing the DW01+G twice - same issue. I tested the FS8205 with a multimeter using online guides - seems just fine in terms of Rons, etc.
I have also tried what is recommended in the DW01+G datasheet which is to short the CSS and VSS pins to get it out of shipping/transport mode.
I also tried replacing the resistor connected to CS with a 2k instead of a 1k (I saw GreatScott did this)

What is causing this? Why do I keep having to short the OD and CS pins?





Thanks!

DATASHEETS:
DW01-G : https://www.ic-fortune.com/upload/Download/DW01-G-DS-10_EN.pdf
FS8205: https://www.ic-fortune.com/upload/Download/FS8205-DS-19_EN.pdf


sleemanj:
> "Shipping Transport Mode"

That's not what that mode is. It is simply that when you connect a cell, the IC was last in over-discharge (because the cell if there was one, suddenly went away at some point looking for all the world like a really rapid overdischarge) and thus power down mode, it needs a kick to get it right again (ie, connect a charger) since it doesn't know that a cell was connected.

Disconnecting a cell will typically get you back into that same "mode" again, needing a kick from a charger (or short) to enliven things again.

AlfroJang80:

--- Quote from: sleemanj on July 02, 2019, 10:28:40 pm ---> "Shipping Transport Mode"

That's not what that mode is. It is simply that when you connect a cell, the IC was last in over-discharge (because the cell if there was one, suddenly went away at some point looking for all the world like a really rapid overdischarge) and thus power down mode, it needs a kick to get it right again (ie, connect a charger) since it doesn't know that a cell was connected.

Disconnecting a cell will typically get you back into that same "mode" again, needing a kick from a charger (or short) to enliven things again.

--- End quote ---

Does that mean that it is intentional that I have to short CS and OD everytime I connect the battery?

sleemanj:
It is "intentional" (better, "expected") that when you connect a battery you have to do something to get the chip into discharge enabled state, in normal applications that would be connecting a charger, in your case it might be shorting the pins.

AlfroJang80:

--- Quote from: sleemanj on July 02, 2019, 10:50:53 pm ---It is "intentional" (better, "expected") that when you connect a battery you have to do something to get the chip into discharge enabled state, in normal applications that would be connecting a charger, in your case it might be shorting the pins.

--- End quote ---

Great! Thanks very much!

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