BQ34Z100: Learning Config Register Max Res Factor / Mas Res Factor Scale

Steve Butler1

Part Number: BQ34Z100

Hello TI,

I understand from the BQ34 data sheet page 52 that Max Res Factor controls how much large of increments that IT data can be updated. I also see the Max Res Scale value.

Questions:

1. Is Max Res Factor a percentage ratio of the Ra stored impedance value? If so, does 255 = 100%

2. Is Max Res Scale is set to 32000, does this mean that the Max Res response is 32000 x the Max Res Factor value? If so, this would mean that the Ra impedance value is allowed to change over a 100x its starting number.

Context: My company has recently changed its setting for Max Res Scale and the IT Track performance now seems unstable and erratic. I am trying to better understand this situation.

Thanks,

Steve

over 4 years ago

0 Wyatt Keller over 4 years ago

TI__Guru** 105760 points

Hello Steve,

This parameter shouldn't need changed from the default unless you're seeing resistance update issues.

It is used to scale the old and new Ra values. Here's another thread that discusses it more: e2e.ti.com/.../581803

Sincerely,

Wyatt Keller

0 Steve Butler1 over 4 years ago in reply to Wyatt Keller

Prodigy 200 points

Hi Wyatt,

Thanks for the link to the thread. Pleases clarify the relationship between Max Res Factor and Max Res Scale...is Max Res Scale a simple multiplier of Max Res Factor?

Thanks,

Steve

0 Wyatt Keller over 4 years ago in reply to Steve Butler1

TI__Guru** 105760 points

Hello Steve,

No it's not a multiplier, the max/min scale factor are used to clamp the Ra scale used internally, these values don't need to be edited for normal operation. The res factor is the multiplier.

Sincerely,

Wyatt Keller

0 Steve Butler1 over 4 years ago in reply to Wyatt Keller

Prodigy 200 points

Hi Wyatt,

Thanks for your response. Just to clarify my understanding.

1. Max/min Res Factor determines how much the RA table can change in one learn update.

2. Max/min Res Scale determines the maximum value that the RA table can learn regardless of the number of updates.

Thanks,

Steve

0 Wyatt Keller over 4 years ago in reply to Steve Butler1

TI__Guru** 105760 points

Hello Steve,

The Res Factor is explained in the TRM and can be toggled:

RFACTSTEP: Enables Ra step up/down to Max/Min Res Factor before disabling Ra updates. Default is 1.

Res Scale clamps the min and max.

Sincerely,

Wyatt Keller

0 Steve Butler1 over 4 years ago in reply to Wyatt Keller

Prodigy 200 points

Thanks Wyatt

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BQ34Z100: Learning Config Register Max Res Factor / Mas Res Factor Scale