BQ24133: 2 Cell battery pack

Fabio Soriano

Part Number: BQ24133
Other Parts Discussed in Thread: BQ24171, BQ24172

Hi Team,

Could you help on this request:

We need to load a battery pack formed by two cells in series, the supplier recommends a charge voltage of 4V / max 4.1V per cell, while I understand that the BQ24133 has a fixed voltage of 4.2V per cell.

Is there any way to adjust this value to lower it as recommended by the battery supplier?

Assuming to load the pack at 4.2V / cell the output voltage must reach 8.4V on the two cells in series.

What is the minimum voltage to which I must supply the BQ (minimum PVCC) for the correct operation of the charger in this condition (max. 1A charge current)?

Regards,

Fabio

over 5 years ago

0 Jeff F over 5 years ago

TI__Guru**** 166576 points

Hi Fabio,

Unfortunately, the BQ24133 is fixed but its higher current siblings, BQ24171 and BQ24172 have resistor adjustable regulation voltage. I recommend one of this devices.

Regards,

Jeff

0 Fabio Soriano over 5 years ago in reply to Jeff F

TI__Expert 4110 points

Hi Jeff,

But assuming to load the pack at 4.2V / cell the output voltage must reach 8.4V on the two cells in series.

What is the minimum voltage to which I must supply the BQ (minimum PVCC) for the correct operation of the charger in this condition (max. 1A charge current)?

Please, let me know!

Regards,

Fabio

0 Jeff F over 5 years ago in reply to Fabio Soriano

TI__Guru**** 166576 points

Fabio,

You need at least PVCC=8.8V for fast charging. As long as PVCC > 8.4/(Dmax=0.97) = 8.7V, the charger will still attempt to charge but much more slowly.

Regards,

Jeff

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BQ24133: 2 Cell battery pack