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DRV2700: Cannot get proper output voltage level gnerated.

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Replies: 15

Views: 676

Part Number: DRV2700

Hello,

I am trying to get a haptic feedback using piezo with DRV2605/DRV2700 (based on application report SLOA255).
When using the DRV2700 with a signal from DRV2605, there is no feedback can be felt. I also notice that the FB pin does not output 1.3V. Thus my PVDD signal is around 10V instead of 65V.

Piezo that is used for haptic feedback - Z63000Z2910Z 1Z 2 (www.digikey.ca/.../j2rm8v)

Attached is the schematics of the haptic driver circuit (the jumpers are set for position for the piezo driver), power supply section and scope reading of SW pin.

Any recommendations?

Regards,

Leon

  • Hi Leon,

    I'll discuss with the team about the actuator your using. Just to confirm, have you also tried by disconnecting the actuator from the DRV2700 outputs?
    It seems that the Boost is not being able to startup, we'll try to help identify why this is happening.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • In reply to Ivan Salazar:

    Leon,

    So far we're not able to reproduce this on our side.
    Is there any new information about this from your side?
    Do you have any update regarding the actuator question? Have you tried by disconnecting the actuator from DRV2700 outputs?

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • In reply to Ivan Salazar:

    Hello Ivan,

    Sorry for not replying sooner. I tested my circuit without actuator and no input signal on pins IN+ and IN-. As soon as EN pin goes high there are dips in supply voltage line and there is no voltage on FB pin. The SW pin has the same pattern as on original image.

    Regards,

    Leon

  • In reply to Leonid Hrapunsky62:

    Leon,

    Not sure if this is possible on your application, but could you add more decoupling capacitance on the supply path, close to the IC (~10uF). This additional capacitance should help with inrush ramping current.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • In reply to Ivan Salazar:

    Leon,

    I'm just checking for updates on this thread. Did you got a chance to test the previous suggestion above?

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • In reply to Ivan Salazar:

    Hello Ivan,

    Happy New Year. I apologize for not replying sooner. I did place a 10µF capacitor in parallel to C10. The results are the same as before. As soon as the EN signal goes high, the 5V supply drops to approx. 3V.

    Regards,

    Leon

  • In reply to Leonid Hrapunsky62:

    Leon,

    Could you please try some simple continuity tests between device pins? I understand it could be hard to measure at the IC pins but maybe you can try by testing on external components, testing on the side that is connected to the IC.
    I'd like to make sure that there is no physical short or something similar in the board.
    This might be an odd test but we cannot replicate this behavior and there are less and less options to debug.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • In reply to Ivan Salazar:

    Hi,

    I'm following up on this thread. Do you have further comments about the above suggestion?

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • In reply to Ivan Salazar:

    Hi Ivan,

    I did test continuity as much as I could (considering the part does not have accessible pins). I did not see any issue with continuity.

    This problem is seen on a number of prototype boards. The reason for long reply was I was looking for another board I created for a different application but using the same design. The results are the same.

    Is it possible that I am damaging the component somehow and the results that I see are due to the failed device? What are potential failures that the device can sustain that will provide me with such a problem? I have a few boards that were never powered, what would be the best way to test these?

    Regards,

    Leon

  • In reply to Leonid Hrapunsky62:

    Hi Leon,

    If there are boards that are working fine, you could try to swap the IC with a non-functioning board to see if the issue comes with the IC or the board.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

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