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Original question:

DRV2700EVM-HV500: The driver didn’t work when I connected to piezo disks.

DRV2700EVM-HV500: can't work well

Yan Wu
Prodigy 20 points
Part Number: DRV2700EVM-HV500
Other Parts Discussed in Thread: DRV2700,

Tool/software:

Hi Sydney,

Thank you for your help. And so sorry for the late response since I'm so occupied after Christmas holiday.

The following photos are what I could provide for fixing the problem. In addition, for the piezo disks, I used one with the capacitance of 8.4686 nF before and another one of 0.8077 nF.

Please feel free to ask me if you need more info from my side.

Best,

Yan

  • 0
    TI__Genius 11275 points

    Hi Yan, 

    No problem! Hope you are having a good new year. 

    What is the application here? Is it for haptics? Typically haptic applications are at much lower frequencies. You are opperating at a high frequency with large duty cycle so the device is likely reaching its limits. 

    Can you try at around 100 hz with a 50% duty cycle? 

    Regards,
    Sydney Northcutt 

  • 0 in reply to Sydney Northcutt
    Prodigy 20 points

    Hi Sydney,

    Thank you for your email!

    I tried the parameters you provided me, please see the following photo. However, it still doesn't work either. Also, I measured the voltage at the output of the piezo driver with an electric meter. It showed zero. So, I was wondering if it was the problem of short-circuit?

    Thanks,

    Yan

  • 0 in reply to Yan Wu
    TI__Genius 11275 points

    Hi Yan, 

    From the screenshot I believe your board is not connected to the GUI. At the bottom of the GUI it should show the EVM name. You must first press connect at the top left. You may have to press the drop down next to connect to select a different option or update the firmware it still does not connect (help -> update firmware). 

    Regards,
    Sydney Northcutt

  • 0 in reply to Sydney Northcutt
    Prodigy 20 points

    I see. I tried again, and it worked!! Thank you so much!

    I would like to ask one question about how to choose the frequency and power in the GUI. I remembered that I just provided capacitance last time and you knew how to decide the frequency. Is there any equation I can use for calculation? Please help me with that.

    Thanks,

    Yan

  • 0 in reply to Yan Wu
    TI__Genius 11275 points

    Hi Yan, 

    Great to hear. Slight smile

    We have graphs in the DRV2700 datasheet that show the max output cabailites with various capacitance loads. These are for DRV2700 in its typical configuration though, not flyback. The flyback configuration will have tighter requirements due to the increased voltage level, but the datasheet plots will be a good starting point. For the flyback configuration we have the below graph showing the max output current that can also be useful here.

    DRV2700EVM-HV500 User Guide:
      

    DRV2700 datasheet:

    Regards,
    Sydney Northcutt

  • 0 in reply to Sydney Northcutt
    Prodigy 20 points

    Thank you so much! Problem solved!