BQ20Z70-V150: BQ20Z75 CHEM ID and PRE CHG

Steel Fang

Part Number: BQ20Z70-V150

Dear TI experts:

we have an old project with BQ20Z75, due to CELL EOL, we need to match the new cell, but we don't intend to change our current HW design.

some questions below that need your answers: (we use BQ evaluation software V0.9.92)

1.How to read the CHEM ID, i can't find it in data flash like other BQ IC?

2.Does PRE CHG setting is valid if we don't use the ZVCHG pin?

3. Does PRE CHG funciton can be set to permanent close? If yes, how to set?

11 months ago

0 Adrian 11 months ago

TI__Mastermind 35361 points

Hey,

The question has been assigned out, we will get back to you by tomorrow.

Regards,

Nick Richards

+1 Dominik Hartl11 11 months ago

TI__Guru 56506 points

#1: Use command Chemistry ID (0x0008). See TRM, A.1.1.6

#2: Yes. See TRM, Table 2-8.

#3: Yes. See TRM, Table 2-8.

TRM: www.ti.com/.../sluu310.pdf

0 Steel Fang 11 months ago in reply to Dominik Hartl11

Intellectual 280 points

Hi Dominik,

after 1st cycle golden sample leaning, the Qmax and update status do not change, can you advise me where the issue is?

0 Dominik Hartl11 11 months ago in reply to Steel Fang

TI__Guru 56506 points

A learning cycle requires a specific sequence. It ideally starts with an almost discharged, relaxed cell at room temperature. The gauge must take an OCV measurement. This is followed by charging until full and relax until the gauge takes another OCV measurement at room temperature. This will update Qmax and be reflected in Update Status. If this doesn't work, then you must check, if the cell was discharged enough and if the passed charge was at least 90% of chemical capacity.

It's not possible to analyze this with a gg file only. This would require a log file of all registers during charge and relax and discharge and relax.

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BQ20Z70-V150: BQ20Z75 CHEM ID and PRE CHG