Hi Tricia,

    This occurs when improper board/system design results in too much impedance between where the BQ24610 senses the battery voltage, and the actual battery. BQ24610 cycling between termination and recharge threshold is not normal operating condition. When battery is near full, it should enter CV (constant voltage phase) and charge current will taper down till termination is hit, and charge is complete. There is no issue with BQ24610 operation, however in that specific customer design they had too much impedance, as well as a visual indicator to customer regarding charge status, which led the user for their specific application to believe there is an error.. For true BQ24610 operation you can evaluate using the BQ24610EVM.

It does not have significance on battery detection algorithm, but with the portion of device operation flowchart, indicating the next step is battery detection. Currently I do not have an estimate on a timeline, but if you let me know how this affects your design, I can work with you to debug further.

Hi Kedar,

Thank-you for your response.

1. I am seeing a charge state from  STAT1/STAT2 = ON/OFF to ON/ON then OFF/ON on one battery pack. Have you heard of this occurring?

2. I have also seen a charge state from ON/OFF to OFF/OFF to ON/OFF when the VFB < VREF after the IDISCHG occurs on another battery pack which seems reasonable since the flowchart show "Indicate battery absent" ?

2. In Figure 19, In the Turn off charge box, there is "Indicate Charge in Progress" - I thought in the other post that this was not correct in the documentation? Sorry if I misunderstood.

Thanks again for any clarifications,

Tricia

Hi Tricia,

   Thanks for providing insight into what is occurring. To better visualize the timings, can you take a scope capture showing the STAT transitional events? Please capture:

• Capture SRN, STAT1, STAT2, Charge current
• SRN, STAT1, STAT2, PH

The inaccuracy is showing charge in progress (STAT1 low) when in Idischg

I will see if we can capture the data you are asking for.

With regards to the Idischg state: if I look at the STAT1 STAT2 at this time - will I see OFF/OFF (per Table 2 STAT Pin Definition)?

I do not see an entry for ON/ON, so assume this case should not occur?

Thank-you for your help Kedar.

Hi Tricia,

    Yes the STAT1 STAT2 should not be low simultaneously (ON/ON). STAT1 and STAT2 high (OFF/OFF) indicate a fault condition.

 With regards to the Idischg state: if I look at the STAT1 STAT2 at this time - will I see OFF/OFF (per Table 2 STAT Pin Definition)? 

This seems like an error condition but it shouldn't be? I only see it once before it changes to OFF/ON indicating fully charged.

Thanks

Hi Tricia,

   Yes you will see STAT1 OFF and STAT2 OFF in the Idischg period (1sec), when STAT1 has been turned off to indicate charging has stopped, and before STAT2 turns ON to indicate termination. The deglitch period for STAT2 to turn on to indicate termination is the brief instant when STAT1 and STAT2 will be off.

Thanks - this explains why in our code we temporarily see STAT1/STAT2  lines go from  ON/OFF to OFF/OFF before full charge OFF/ON and in the test case when goes from  charging to Idischg and see VFB< VRECH (we observe these states: ON/OFF to OFF/OFF back to ON/OFF.

So to recap:

Figure 19 (Idischg box needs updating),

Figure 17( Vfb < Vlowv change to Vfb>Vlowv or change YES/NO), and

Table 2 (add OFF/OFF Idischg for 1 second) will all be updated to reflect these cases?

Thanks again,

Tricia