• State Resolved
  • Locked Locked
  • Replies 7 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 995 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ76PL455EVM: Powering up BQ76PL455 EVM

Vikram Jain
Intellectual 485 points
Part Number: BQ76PL455EVM

Dear All, 

I have a design question regarding powering up the BQ EVM.

Currently what i have is I have two connectors

Connector 1 - connecting vesnse0 to 16 (Cell VSENSE Connecting on J1 BQ76PL455 EVM)

Connector 2 - BAT0 and BAT16 to power the BQ IC

The procedure followed is connecting connector 2 first and then Connector 1. What i would like to know is do we really need to power the IC 1st and then the Vsense ? or can we just connect all the J1 pins on BQEVM and just use that connector for powering the BQ IC and VSENSE all in same time ? 

Regards

Vikram Jain 

  • 0
    TI__Genius 11480 points
    Hi Vikram,

    I don't recommend using separate connectors for power/vsense. I recommend using one connector with separate cables, so that they are connected at roughly the same time (+/- several fractions of a second). You could even use one cable for BAT16/Power if you're ok with the little bit of I*R drop you will see.

    If you do two separate connectors with appreciable time, i think you will find that you have some "unexpected" current paths (IE, through the back-back diode from TOP to VSNS16.
  • 0 in reply to David Wiest Jr
    Intellectual 485 points
    Okay I will try that. Also what i have seen is that if Base Device in the stack some how looses the power then all others in the stack remain poweered on is there any sort of work around to this so that when the base device shuts down expectedly/unexpectedly rest of the stack should also power down ?
  • 0 in reply to Vikram Jain
    Intellectual 485 points
    Can someone please help and respond ?
  • 0 in reply to Vikram Jain
    TI__Genius 11480 points
    Hi Vikram,

    You can configure the COMM_PD_PER bits in the CTO register. This will power down the pl455 if communications have not been received after the programmed period of time.

    Details are in the datasheet.
  • 0 in reply to David Wiest Jr
    Intellectual 485 points
    Hi David,

    Urgent can you please reply to this thread ?

    e2e.ti.com/.../636430
  • 0 in reply to Vikram Jain
    Intellectual 485 points
    Hi David, Regarding the J1 connector the BQ EVM guide has the following note

    "Although it is not strictly required due to the presence of on-module protection circuitry, when
    using a battery stack, it is recommended to first apply power from the top and bottom of the
    stack to BAT16 and BAT0, respectively, in order to power the bq76PL455EVM, before
    applying power from the intermediate stack cell connections to BAT0S, BAT1, BAT2 through
    to BAT15, and BAT16S. This is achieved using a make-first, break-last type battery
    connector if hot plugging or using switches to sequence power application."

    So do you still stand with your above comment that power and VSENSE can both go on same connector J1 can be inserted at the same time ?
  • 0 in reply to Vikram Jain
    TI__Genius 11480 points
    Hi Vikram,

    We see many customers that use only one connector to cut cost of parts & assembly. The connection of BAT16 & BAT0 gives a more controlled and survivable hot plug result. If you include the proper clamping & resistive damping circuits (noted in the documentation) it is likely not needed.

    You could do this, i suppose, if desired.