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BQ76PL455EVM: VP1, VIO and VDig not generated on Connecting Batteries

Nidheesh BR
Expert 1170 points
Part Number: BQ76PL455EVM
Other Parts Discussed in Thread: BQ76PL455A-Q1, BQ76PL455-Q1

Hi,

I am Using BQ76PL455EVM for implementing Battery management system.

I have connected 6 Li ion cells in series.

Vtop: 23V

As per BQ76PL455A-Q1 datasheet, VP1, Vdig and VIO will be generated using NPN transistor Q17 on EVM.

Why there is no Voltage across VP1, Vdig and VIO?

But when I apply, VCC from external TMS570 launchpad, it works fine.

So my Question is: Does BQ76PL455-Q1 IC require an external power supply to turn ON NPN_base ?

Waiting for a quick reply.

  • 0
    TI__Genius 11480 points
    Ritul,

    In a base (master) device, VIO should be supplied by the same supply as the MCU. For a stacked device it is supplied by the VP regulator.
  • 0 in reply to David Wiest Jr
    Expert 1170 points

    Hello David,

    Thanks for your reply.

    My application is for single device configuration and I am designing a PCB for it.

    What is the difference in configuration and wiring/Power supply between Single device configuration and Stacked configuration?

    How will the BQ76PL455A-Q1 get powered ON and function correctly? What all voltages i need to give as Input to the IC? And what all voltages be generated on applying them?

    Whether I need to use an external voltage converter to give voltages to VP1, Vdig and Vio ? 

    Waiting for your convincing solution.

  • 0 in reply to Nidheesh BR
    TI__Genius 11480 points

    Ritul,

    The pl455 has an on-board linear regulator that utilizes an external BJT. For a single ended  use case, VP supplies VDIG,  etc.  The only external supply  needed is the 5V /3.3V for  the  MCU and CAN if used. It  can be the  same supply.

    There  is  an always on internal supply, V5VAO, that keeps the  bare minimum internal circuitry active and waiting for a wakeup pulse or tone on the daisy chian. When wakeup is received, then everything else  (including VP) powers up.

    I strongly recommend reading through the documentation found here:www.ti.com/.../technicaldocuments .

  • 0 in reply to David Wiest Jr
    Expert 1170 points

    Thank You David!!

    ""There  is  an always on internal supply, V5VAO, that keeps the  bare minimum internal circuitry active and waiting for a wakeup pulse or tone on the daisy chian. When wakeup is received, then everything else  (including VP) powers up.""

    This solved my problem.

  • 0 in reply to Nidheesh BR
    TI__Genius 11480 points

    You are welcome Ritul. I  am always  happy to help as  i can