BQ4050: BQ4050 to support one cell setting

Eric Lai

Part Number: BQ4050
Other Parts Discussed in Thread: BQSTUDIO, BQ34Z100-G1, BQ40Z50

Hi Expert,

Will need your support to know how to design the BQ4050 to support one cell setting.

Condition:

--System only connect to One individual 12.8V battery directly (4 cells in series inside).System not connect to individual 4 cell separately

--LiFePo4

--Consider the BQ4050 for system side gauge

Now We connect this individual 12.8V battery to BQ4050 EVM directly at VC1,then short the VC1~VC4 together. Since we think this is one cell for BQ4050.And system can not connect to individual 4 cell separately.

Then using the bqstudio to communicate with EVM and this individual 12.8V battery.

But now we see the voltage of CELL 1 show 0V from bqstudio.

But use one 4V battery to instead of the 12.8V battery with same configuration.The cell1 reported the voltage correctly.

We try to increase the Safety Cell Overvoltage and Safety Cell Overvoltage setting to 15V in case the OVP is triggered, but still not work.

So will need you to advise us how to configure the EVM and setting the bqstudio.

If possible, can you also run the bqstudio with this conditions and forward the log files to us.

Then we follow your setting directly.

Thanks

Best regards,

Eric Lai

Field Application Engineer

Texas Instruments Taiwan Limited

O: +886-2-2175-2582

M: +886-909-262-582

E-Mail:Eric.Lai@ti.com

over 5 years ago

0 Wyatt Keller over 5 years ago

TI__Guru** 105590 points

Hello Eric,

I don't believe there is a way to use the bq4050 without access to the individual cells, you will need to use a top of stack gauge like the bq34z100-g1 to gauge the pack without the cell voltages.

It is also mentioned in this thread for the bq40z50: https://e2e.ti.com/support/power-management/f/196/p/911535/3368628?tisearch=e2e-quicksearch&keymatch=bq40z50%20pack#3368628

Sincerely,

Wyatt Keller

0 Eric Lai over 5 years ago in reply to Wyatt Keller

TI__Expert 4940 points

Hi Expert,

Thanks for you support.

May we know why BQ4050 not supported to work for one cell (12.8V) setting.

The datasheet mentioned it support the 1 series to 4 series and max voltage on VC pin is 30V,

The used guide also suggested to A short should be placed across unused voltage sense inputs.

Will need to explain these items to the engineers.Pls advice.

Thanks

Best regards,

Eric Lai

Field Application Engineer

Texas Instruments Taiwan Limited

O: +886-2-2175-2582

M: +886-909-262-582

E-Mail:Eric.Lai@ti.com

0 Wyatt Keller over 5 years ago in reply to Eric Lai

TI__Guru** 105590 points

Hello Eric,

This wouldn't be a 1 cell application because the pack contains multiple cells. Trying to use a multi cell gauge that usually measures each cell voltage could cause protections to trigger and other errors.

Using a top of stack gauge would be the easiest gauge to implement because it is designed for you application.

Sincerely,

Wyatt Keller

0 user1869450 over 5 years ago in reply to Eric Lai

TI__Prodigy 30 points

bq4050 EVM contains BQ296103DSGR (hardware OVP protector). BQ296103DSGR will be trigger if the VC higher than 4.5V and turn off FETs. bq4050 will receive FUSE below from BQ296103DSGR. please refer to bq34z100-g1 for such application.

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SungYi Chen

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BQ4050: BQ4050 to support one cell setting