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BQ76952: Current reading not changing after certain value

Hareesh Gorle
Prodigy 30 points
Part Number: BQ76952
Other Parts Discussed in Thread: BQSTUDIO

Tool/software:

Hi team,

We are using BQ76952 AFE to read cell measurements.

We are able to read cell volt measurements properly, but the current measurement is not reading properly. The shunt resistor value is 0.5 milli ohms.

When we are applying 1 A, it is reading 65. So, We changed the following register values in the AFE.

CC gain for 0.5mohm shunt : 14.9536(Little endian (IEEE-754) value 41 6F 41 F2)

Capacity gain for 0.5mohm shunt :Little endian (IEEE-754) value 6A 1C 08 4B

DA configuration register value changed to 0x06.

However the value is still showing 65 for 1A and 134 for 2A respectively.

Kindly help us to resolve the issue.

Best regards,

Hareesh

  • 0
    TI__Intellectual 1600 points

    Hello Hareesh,

    Your CC Gain is correct. Are you reading the current through BQStudio or are you using commands? If you are using commands, what commands are you sending?

    Also, is this error occuring with all CC current readings?

    Lastly, have you tried increasing the DA configuration register? You are only applying 1A so I would not think the 16-bit current reading is reaching the max 32767, but I want to see if this changes anything out of curiousity.

    Regards,

    Rohin Nair

  • 0 in reply to Rohin Nair
    Prodigy 30 points

    Hi  ,

    Thanks for the reply.

    Rohin Nair said:
    Are you reading the current through BQStudio or are you using commands? If you are using commands, what commands are you sending?

    We reading current through following commands:

    #define CC2Current   0x3A

    BQ769x2_ReadCurrent(CC2Current);  

    Rohin Nair said:
    Also, is this error occuring with all CC current readings?

    yes, the error occurring with all CC current readings.

    Rohin Nair said:
    Lastly, have you tried increasing the DA configuration register?

    Yes, I checked with different values but the issue is same.

    Rohin Nair said:
    You are only applying 1A so I would not think the 16-bit current reading is reaching the max 32767, but I want to see if this changes anything out of curiousity.

    The current reading is reached max 32767 when I applied 56 Amps.

    applied current   -  CC current reading

    1A                     ->  65

    2A                    ->   134

    56A                  ->    32767

    Best regards,

    Hareesh

  • 0 in reply to Hareesh Gorle
    TI__Intellectual 1600 points

    Hello Hareesh,

    This is very unusual. Have you tried sending other commands to see if any communication is still occurring? Is this the only device where you are noticing this issue?

    Regards,

    Rohin Nair