BQ40Z60: Protection delay time accuracy

K. Sasaki14

Part Number: BQ40Z60
Other Parts Discussed in Thread: BQ40Z50

bq40z60 has many protection functions.

There are voltage , current, temperature and so on protection functions. And they have detection delay and recovery delay setting.

I would like to know these delay time accuracy.

Datasheet has only tACC(current fault delay time accuracy) specification +/-10%, but the other delay accuracy parameters are not on the datasheet.

Furthermore there are Hardware based protection (AOLD, ASCC and ASCD) and Software based protection, and I think the delay time accuracy is different between Hardware based protection and Software based protection.

So please let me know about the following.
- Can we use +/-10% as the all software based current fault protection delay time accuracy?

- What is the Hardware based protection delay time accuracy?

- I think the delay time of voltage, temperature and so on protection is software based. Thus can we use +/-10% as these fault protection delay time accuracy?

I don't require guaranteed value, reference vale is OK.

Best Regards,
Kohei Sasaki

over 3 years ago

0 Andy Liu (BMS) over 3 years ago

TI__Guru 52115 points

I see a similar question about bq40z50 was asked a few days ago.

See our reply in the following thread.

https://e2e.ti.com/support/power-management/f/196/t/915653

Andy

0 K. Sasaki14 over 3 years ago in reply to Andy Liu (BMS)

Guru 10200 points

Do you have no more information about protection delay time accuracy?

I think protection delay time accuracy is important information for the device which has protection function.

Must I allow no matter how long the delay time becomes?

Best Regards,
Kohei Sasaki

0 K. Sasaki14 over 3 years ago in reply to K. Sasaki14

Guru 10200 points

Hi team,

Is there no additional information?

Best Regards,
Kohei Sasaki

0 Andy Liu (BMS) over 3 years ago in reply to K. Sasaki14

TI__Guru 52115 points

I have found some answers in one old thread.

See the following thread.

Andy

0 K. Sasaki14 over 3 years ago in reply to Andy Liu (BMS)

Guru 10200 points

Andy-san,

Thank you for your reply.

Doesn't protection FETs turn off by OC or SC etc?

Is the situation that protection FETs become OFF only Hardware based protection and Permanent Fail?

I understand Firmware based protection detection delay time is added max 2s to setting value.
How about the Hardware based protection and permanent fail delay time tolerance?

Best Regards,
Kohei Sasaki

0 Andy Liu (BMS) over 3 years ago in reply to K. Sasaki14

TI__Guru 52115 points

I would need to check internally and then get back to you.

Andy

0 Andy Liu (BMS) over 3 years ago in reply to Andy Liu (BMS)

TI__Guru 52115 points

Here is some feedback I have got.

a) The AFE based protections are covered by tACC in the datasheet.

b) The Permanent Fail timing is a little different as it is firmware-based and therefore I think its delay time accuracy should be up to +2 seconds.

Andy

0 K. Sasaki14 over 3 years ago in reply to Andy Liu (BMS)

Guru 10200 points

Andy-san,

What are the AFE based protections? Is it not included Hardware based protection such as OC and SC etc..?

I think OC, SC, OV and UV etc are firmware based protection.

What is difference between AFE based protection and Firmware based protection? I would like to know the protection items.

Best Regards,
Kohei Sasaki

0 Andy Liu (BMS) over 3 years ago in reply to K. Sasaki14

TI__Guru 52115 points

The AFE based protections mean the three hardware-based protections: AOLD, ASCC, and ASCD1,2.

What do you mean by OC, SC, OV, and UV?

Andy

0 K. Sasaki14 over 3 years ago in reply to Andy Liu (BMS)

Guru 10200 points

Andy-san,

I mean OC, SC, OV and UV are cell over and under voltage, over current and short circuit protection.

I understand as the following from your answer,

Hardware based protections, AOLD, ASCC and ASCD1,2 delay time tolerance is covered by tACC in the datasheet.

The other detection delay time tolerance is added max 2s because primary and secondary safety features are firmware based protections.

Datasheet has current protection timing requirement, and it is described as OCD, SCC and SCD1,2.
are these error? I thought AOLD, ASCC and ASCD1, 2 are correct description.

Best Regards,
Kohei Sasaki

0 Andy Liu (BMS) over 3 years ago in reply to K. Sasaki14

TI__Guru 52115 points

I don't think these are typos. My understanding is that they just follow a slightly different naming convention. I assume the first letter A probably means AFE.

Andy

0 K. Sasaki14 over 3 years ago in reply to Andy Liu (BMS)

Guru 10200 points

Andy-san,

If your opinion is correct, I think OCD should be changed OLD.

However I understood that datasheet timing specification is about hardware based protection, and the other protections delay time is added max 2s.

Best Regards,
Kohei Sasaki

0 Andy Liu (BMS) over 3 years ago in reply to K. Sasaki14

TI__Guru 52115 points

I only see OLD in Section 2.8.1 of BQ40z60 TRM.

Andy

0 K. Sasaki14 over 3 years ago in reply to Andy Liu (BMS)

Guru 10200 points

Andy-san,

I think it is better to match the protection feature name between datasheet and TRM.

Best Regards,
Kohei Sasaki

0 Andy Liu (BMS) over 3 years ago in reply to K. Sasaki14

TI__Guru 52115 points

I agree.

Let me check internally again and will let you know if I get some good explanations.

Andy

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BQ40Z60: Protection delay time accuracy