I am using bq25010 to charge my battery 190mAh Li-Polimer cell using USB.
Current meter is connected in series between battery and bq25010.
I am able to detect following states
Fast charge in progress (USB present) - STAT1=ON , STAT2=OFF
Speel mode (USB absent) - STAT1=OFF , STAT2=OFF
But when battery charges fully, Current in meter drops below 1.9mA, but
I am not getting Charge Done - STAT1=OFF, STAT2=ON
Is this feature really supported in the IC?
STAT1 and STAT2 are open drain, so configured for internal pullup. They are working as I am getting "Fast charge in progress" and "Sleep mode".
Need your thoughts that why I am not getting Charge Done. Load is not dis-connected during charging.
Yes, this feature is supported; the IC should terminate at regulation voltage. Can you measure the battery voltage and see if it reaches voltage regulation level (4.2V) and still IC does not terminate?
Yes battery reaches to 4.2V and charging current drops to <1.9mA, it means battery charging terminated.
But that is not reflected on pins STAT1 and STAT2. Why i am not getting these signals as Charge Done?
That's what i am asking, are STAT1 and STAT2 pins reflects Charge Done to micro-processor?
Please see figure 3 in the datasheet. The charger enters a taper detector phase then terminates after the charging currents drops below the termination voltage. Itaper is set using equation 3 in the DS and I termination is set using equation 3 in the DS (what are the Iterm and Itaper in your design?). Please see if these parameters are set correctly. Again, the charge done state should be reported after the termination occurred as shown in table 2 in the DS.
As per my circuit Rset=1.5Kohm
As per specifications on DS
So that Itaper=53mA approx.
and Iterm=3.84mA approx.
So even though my charging current drops below 2mA (read using Current Meter), why STAT1 and STAT2 did not reflect Charge Done?
You may be getting a switching spike via the switcher that is resetting the termination. Disable the swticher with the EN pin.
If this lets the charger terminate, then maybe more capacitance on the input of the switcher will help.
In addition to Charles post, also try to increase the termination & taper currents and see if that makes a difference. Please send me some plot pictures of voltage and current at BAT/OUT.
Now working on it, will need time to come out with results.
Thanks to all.
Found it, now working.
During charging my load was connected. I did not disable the load. That's why was not getting Charge Done.
Now I put whole load into power down mode and I got Charge Done.
Thanks a lot to all.
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