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BQ28Z610-R1: System Side Gauge IC for 2S application...

SelvaKumaran R
Expert 3015 points
Part Number: BQ28Z610-R1
Other Parts Discussed in Thread: BQ24610, PMP9769, BQ34Z100, BQ27220, BQ34Z100-G1

Hi Team,

One of my customer wanted to use BQ28Z610-R1 on system side gauge along with BQ24610 charger for 2S application. Battery has inbuilt protections and doesn't need the protections of BQ28Z610-R1. Can we use this device for such application? How to connect unused connections like VC1, VC2 etc.. Battery capacity to be monitored is 16000mAH. Also, please let me know how to interface the battery thermistor with BQ24610 & BQ28Z610-R1.

-Selva

  • 0
    TI__Mastermind 24870 points

    This should be a pack side gauge. It has connections to individual pins. I would recommend taking a look at the reference schematic first.

  • 0 in reply to Kang Kang
    TI__Expert 3015 points

    Hi Kang,

    Yes. I am aware of the same. Would like to know if we can use on System side and can we bypass some unwanted circuit like the way done in PMP9769. if so, what would be the limitations. Do you have any better option for System side 2S gauge?

    -Selva

  • 0 in reply to SelvaKumaran R
    TI__Expert 3015 points

    Hi Kang,

    Just to clarify, connecting the VC1/VC2 to VBAT/2 and leave the DSG/CHG OPEN while operating on system side. Customer is looking for a simpler solution for 2S and cheaper. We have some competition to compete. your suggestion would help.

    -Selva

  • 0 in reply to SelvaKumaran R
    TI__Mastermind 24870 points

    Hello Selva,

    We have a bq34z100 that could be used in this case.

    You can also look at a voltage divider solution using a bq27520 or bq27220.

    Thanks!

  • 0 in reply to Kang Kang
    TI__Expert 3015 points

    Hi Kang,

    BQ34z100 cost is higher and customer is not interested. Bq27520 and bq27220 are available only in BGA package. Customer is requesting for non-bga package. Customer is looking for a simpler gauge device and comparing some devices from competition with simple coulomb counter. 
    any comments on the BQ28Z610-R1 usage on system sides as mentioned in my earlier post? this device looks to be cheaper than Bq34z100.
    -Selva

  • 0 in reply to SelvaKumaran R
    TI__Mastermind 24870 points

    Hello Selva,

    I see, in that case, for 2S support, can the customer connect each cell individually to VC2, VC1 and VSS?

    If they can implement that on the system side, it may work.

    The only other thing is please make sure the customer looks at the DS abs max and compare it to the system board voltages. Many pins of the device were intended to be in a battery pack PCB, where the highest potential voltage will be no higher than the CHG/DSG pumps itself.

  • 0 in reply to Kang Kang
    TI__Expert 3015 points

    HI Kang,

    Customer cannot connect VC2,VC1 from battery cell as they are exposed only to PACK+/PACK-. I felt connecting PACK+ to VC2, PACK and PACK+ /2 (by local resistor divider n/w) to VC1 will emulate the 2S configuration for BQ28Z610-R1. Leave the CHG,DSG pis open as no protection needed. This way, i thought we can use from system side. If this will not work, i would like to use the BQ34Z100-G1. Please find the circuit attached. can you please verify once for the System side gauge connection. Need confirmation on SRP/SRN connection and GND reference. Will the current polarity for chg/dsg done properly?

    -SelvaTIDA-SMXXXA1(001)_Sch.PDF

  • 0 in reply to SelvaKumaran R
    TI__Mastermind 24870 points

    Hello Selva,

    I don't recommend doing this with a resistor divider. You are emulating that and burning power. Then you could have messed up balancing.

    The bq34z100-G1 is better for this, but only if the package is acceptable.

    Can you check with the EVM. The EVM schematic is implemented SRN SRP such that it is a system side application.