• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 30 subscribers
  • Views 205 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.

DRV8662: Cascade multiple drivers together

ikellymo
Prodigy 100 points
Part Number: DRV8662

I am working on a three channel piezo driver board and would like to cascade channels 2 and 3 off the boost converter from channel 1 to reduce quiescent current. I think I read somewhere that this is possible, but would like to know what pins are required to be connected. Right now I have VPUMP, SW, VDD and VBST disconnected on CH2 and CH3, with all three PVDD connected together. 

Is VDD internally routed to the amplifier section to set common mode voltage of the low-side to VDD/2?

Thank you

  • 0
    TI__Guru* 84915 points

    Hi, 

    Welcome to E2E and thank you for your interest in our products!

    Regarding your question about VDD, you are right. Internally, the common mode voltage is set at VDD/2. 

    Regarding your application, it is important to know that the SW inductor is sensitive to the current increments. Having three DRV8662 in cascade sharing the same VBST level could result in a device damage. I would recommend to connect each device to its independent switching circuitry. If this is not an option for you, I would suggest to use an external PVDD using the following procedure:

    -          Remove inductor

    -          SW=GND

    -          BST (separated from PVDD)=Open

    -          Cboost will be filtering cap for PVDD

    -          Remove feed-back resistor and connect FB to VDD


    Best regards,
    Luis Fernando Rodríguez S.