BQ40Z50: the tolerance of delay time

Cheer Hsu1

Part Number: BQ40Z50

For BQ40Z50, how to calculate the tolerance of delay time of AOLD, SCD and SCC?

e.g.1) If AOLD delay time setting is 31ms, how about the tolerance of delay time?

e.g.2) If SCD delay time setting is 915us, how about the tolerance of delay time?

e.g.3) If SCC delay time setting is 915s, how about the tolerance of delay time?

0 Batt over 4 years ago

Hi Cheer,

These parameters are by design and have been characterized. AFE actions based on these are by the timer table in the TRM appendix A.

We provide nominal values as they are the step values in addition to fault detect time.

0 Cheer Hsu1 over 4 years ago in reply to Batt

Hi Batt,

I know that the delay time of HW current protection is based on appendix A to set.

But I would know the tolerance of every step delay time how to define?

e.g. If AOLD delay time setting is 31ms, it will be guarantee 31ms+/-??

e.g. If SCD delay time setting is 915us, it will be guarantee 915us+/-??

e.g. If SCC delay time setting is 915us, it will be guarantee 915us+/-??

0 Batt over 4 years ago in reply to Cheer Hsu1

Hi Cheer,

That is defined by the hw and in the DS, so you can work with that.

0 Cheer Hsu1 over 4 years ago in reply to Batt

Hi Batt,

Sorry to bother you again, please help me to confirm below:

HW delay time tolerance is based on “t_DETECT (Current fault detect time)” and “t_ACC (Current fault

delay time accuracy)”, right? Does the following example correct for BQ40Z50?

e.g. If AOLD delay time setting is 31ms, it will be guarantee 31ms+/-??

The tolerance is 31ms+/-10% and +160us for Max, so it's 27.9ms~34.26ms

e.g. If SCD delay time setting is 915us, it will be guarantee 915us+/-??

The tolerance is 915us+/-10% and +160us for Max, so it's 823.5us~1166.5us

0 Batt over 4 years ago in reply to Cheer Hsu1

Hi Cheer,

Your example is correct.

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