BQ35100: INITCOMP

Hello Kagawa,

INITCOMP only has to do with initial startup. It should stay set after the gauge is active and initialized.

Are you seeing the INITCOMP bit toggling during normal operation?

Sincerely,

Wyatt Keller

Hi Wyatt-san,

After GE=H, there is a timing where INITCOMP goes high 1.2s later, followed by INITCOMP going low 1s later. The reproduction rate is low, but it is occurring at arbitrary times.
Is there any possible cause for this?

Regards,
Kagawa

Hello Kagawa,

What is the occurrence rate for this behavior? The only time the bit should be reset is during some type of reset event. What exactly is happening in the system (commands too) when the bit is cleared?

Sincerely,

Wyatt Keller

Hello Wyatt-san,

The waveforms were measured by creating a program to check that INITCOMP=H at 100ms intervals during the first 10s after startup.
The success waveform (Figure 1) takes slightly longer to return an ACK, while the failure waveform (Figure 2) is shorter, with a response value of 00.

1. What is the estimatied cause of the following phenomena?

Figure 1 Successful waveform (INITCOM = H)



Figure 2 Failure Waveform (INITCOMP = L)


2. Answer to your question
> What exactly is happening in the system (commands too) when the bit is cleared?
-->
The incidence at room temperature is roughly 1%, which is very low. The waveform at startup recognizes that no reset has occurred. The command is shown above.

Regards,
Kagawa

Hello Kagawa-san,

It may be best to reset the gauge when this occurs so it re-initializes. It seems something during the initialization process fails, or possibly the gauge has some type of momentary brownout which would cause the gauge to re-initialize.

Sincerely,

Wyatt Keller

Hello Wyatt-san,

I understand that Figure 2 in the previous thread is the waveform when quenched with an icer, so it needs to be reset and re-initialized under those conditions.
(No measurable level of brownout has occurred under these conditions.)

Figure 3 shows the measurement results under normal temperature environment (24°C room temperature), where the same phenomenon occurs in 100ms units (no more than this).
(Even under the conditions shown in Figure 3, there is no measurable level of brownout.)
If possible, we would like to initialize the Coulomb counter by retrying without putting in a reset.
(It is difficult to reset each time a brownout occurs due to equipment limitations.)
Also, is there any suspicion of IC failure?

Figure 2 in the previous thread shows the waveform when quenched with an icer, so I understand that it is necessary to reset and reinitialize the IC under those conditions.
(No measurable level of brownout has occurred under these conditions.)

Figure 3 shows the measurement results under normal temperature environment (24°C room temperature), where the same phenomenon occurs in 100ms units (no more than this).
(Even under the conditions shown in Figure 3, there is no measurable level of brownout.)

If possible, we would like to initialize the Coulomb counter by retrying without putting in a reset.
(It is difficult to reset each time a brownout occurs due to equipment limitations.)

Also, is there any suspicion of IC failure?

Figure 3

TP: Outputs "H" when INITCOMP = "H"; remains "L" when INITCOMP = "L".

Regards,
Kagawa

Hello Kagawa-san,

I will need to look into this further, I will respond tomorrow.

Sincerely,

Wyatt Keller

Hello Wyatt-san,

Customer said:
I have rewritten the FW multiple times and checked it again, but the result is the same as the last time and has not changed.

Should the customer request an IC analysis?

Regards,
Kagawa

Hello Kagawa-san,

I think it is very unlikely that anything would be found from IC analysis at TI, the code shows the exact behavior of this bit. It seems there may be some poor timing of events that is causing some type of reset to occur. This can be from brownout, I2C communication too quick causing a WDT reset, etc. This is happening to 1% of the gauges and is reproducible only with the 1% that have failed before.

Sincerely,

Wyatt Keller