BQ76952: BQ76952-FAQ Related Query

AJAY R

Part Number: BQ76952

Tool/software:

Please help me to understand what will happen if I convert 16 cell to 14 cell bms by shorting cell 15 and 16 (VC15-16). As I have tested on bms, it is not affecting as much.

One more question, what is sink source current for the same part number as I am planning to drive parallel mosfets for both charging and discharging.

over 1 year ago

0 Alexis_H over 1 year ago

TI__Genius 17915 points

Hello AJAY,

Please refer to Table 16-3. Terminating Unused Pins in the BQ76952 Datasheet for the recommended steps for how to terminate unused pins. I do not recommend shorting cells 15 and 16 as cell 16 is important for cell balancing and measurement taking.

Section 7.8 Precharge (PCHG) and Predischarge (PDSG) FET Drive in the datasheet should give you the sink source current for those FETs.

These resources may also be useful is you plan on using Parallel FETs for both charging and discharging.
Multiple FETs with the BQ769x2 Battery Monitors (Section 5 Parallel FET Test Circuits)
Parallel Paths with the BQ76952 Battery Monitor Family

Best Regards,
Alexis

0 AJAY R over 1 year ago in reply to Alexis_H

Prodigy 90 points

Thanks, I understood.

I am using CHG (pin 45) NMOS Charge FET drive output could you please help me to understand sink source current capability of the pin.

0 Alexis_H over 1 year ago in reply to AJAY R

TI__Genius 17915 points

Hello AJAY,

We do not characterize the sink source current there. However, we recommend no more than 40 microamps on the CHG pin.

Best Regards,
Alexis

0 AJAY R over 1 year ago in reply to Alexis_H

Prodigy 90 points

Thanks. Looking to the sink source current, its quiet challenging to drive multiple top side mosfets using afe.Do you recommend driving high side fet with afe, or need to add separate driver. Our total system input gate capacitance is 60nF for charge fets.

0 Max Verboncoeur over 1 year ago in reply to AJAY R

TI__Mastermind 25980 points

Hi Ajay,

I recommend taking a look at this application note. We've tested up to 24 FETs total on the internal driver and seen good results.

https://www.ti.com/lit/an/sluaa09a/sluaa09a.pdf

Regards,

Max Verboncoeur

Power management

Power management forum

BQ76952: BQ76952-FAQ Related Query