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BOOSTXL-DRV8305EVM: Gate drivers for each bridges do not give proper signal

Savas PINAR
Intellectual 270 points
Part Number: BOOSTXL-DRV8305EVM
Other Parts Discussed in Thread: DRV8305, LMR16006

Hi everyone,

I designed DRV8305 boostxl myself  for using with c2000 piccolo launchpad.  I have exploited from schematic of drv8305 boostxl and used recommended components in schematic. But when I try to work the system, I  do not take the required gate pulses from GHx and GLx pins. Is there anyone encountered and fixed  this problem . I know my question is not in detail, sorry. But like I said I did not use any component or chip different from here. ( www.ti.com/lit/ug/slvuai8/slvuai8.pdf ) . Thanks for your any helps.

Savas

  • 0
    TI__Guru** 114905 points
    Hi Savas,

    Are all the components placed on the PCB?
    Which DRV8305 device did you use?
    What do you observe on GHx and GLx?
    What is the voltage on the nFAULT pin? If fault is low, have you used Table 5 of the datasheet to determine the type of fault?
    What is the voltage on DVDD, AVDD, VCP_H, VCP_LSD?
  • 0 in reply to Rick Duncan
    Intellectual 270 points
    Hi Rick,

    Thank you for return. yes placed on PCB. My gate driver is DRV8305N. nfault shows 0.73 V. AVDD is 5 V. DVDD is 3.27 V. VCP_H is 11.5 V and VCP_LSD is 0 V. GHx and GLx show noise-like figures and on mV levels. And PWM pins from piccolo also show weird figures. When I used normal DRV8305EVM boostXL with piccolo, PWM pins show pulses as expected. I do not understand how and why my design can affect the signals from piccolo.

    regards,
    savas
  • 0 in reply to Savas PINAR
    TI__Guru** 114905 points

    Hi Savas,

    Is EN_GATE high when VCPH is 11.5V and VCP_LSD is 0V? If so this should not occur.

    Your best debug aid is comparing the existing DRV8305EVM BoostXL board with your board.

    Also, if you have a second board built try it.

  • 0 in reply to Rick Duncan
    Intellectual 270 points
    Hi Rick,

    I think I miss something. I did not use LMR16006, because I thought piccolo board supplies 3.3 volt itself and my board by using usb power. But am I wrong with this thought? Does LMR16006-converted 3.3 volt affect the whole system differently? maybe my problem is with power sequencing?

    Regards,
    Savas
  • 0 in reply to Savas PINAR
    TI__Guru** 114905 points
    Hi Savas,

    The LMR16006 is needed.

    According to the User Guide:

    • Onboard LM16006 step-down buck regulator to provide 3.3-V power to the Launchpad

    The USB connector on the Launchpad powers the emulator side of the Launchpad, but not the C2000 side. The LMR16006 powers the C2000.
  • 0 in reply to Rick Duncan
    Intellectual 270 points
    Hi Rick,

    I thought that JP1, JP2 and JP3 jumpers on the Launchpad provides power both emulator and MCU side. But now I understand I was wrong.
    Thank you.

    Savas