BQ79606A-Q1: BQ79606 safety manual SM107 and SM108 implement issues

Hi Zizhen,

Zizhen Yu said:

SM107: when we use this SM, sometimes, the AFE report LP_FILT=Fault, more frequent, but fortunately not continuous report this fault. So, is there any possibility cause for suspicion? Based on your experience.

This can be because of reference voltages used by the device internally or how noisy the input is. If you are not seeing it continuously, I would explore the filtering at the input. 

Zizhen Yu said:

SM108: this SM doesn't have detailed test sequence in safety manual and datasheet, so we do it refer to SM203. but when in inject fault in SM108, AFE still not report the fault, which cause this SM test fail. So can you provide a detailed test sequence for this SM108? Is there anything we should pay special attention to?

I will look into this. Can you outline your process at the LPF_FLT injection? Are there any registers you write to prior to writing 0b1 to LPF_FLT_INJ in the DIAG_CTRL1 register? 

Hi Anthony:

Thank you for your answers.

1. For SM107, we will add more debounce time to filter this fault, maybe it's OK;
2. For SM108, the SM108 and SM203 only execute once at power up, so the general sequence is: wake-up BQ79606 and configure it, then we start execute SM108 and SM203 together according to following picture.

There are two special points to note in execute SM108:

1. we execute SM108 and SM203 at one test sequence, which means we do SM108 and SM203 together. Does it will have any influence?
2. we execyte SM108 at continue conversion mode, not at single conversion mode. Does it will have any influence too?

Best Regards