• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Subscribers 29 subscribers
  • Views 1736 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.

BOOSTXL-DRV8323RH: Buck Regulator: Supply adjusment

Xavier Queffelec
Intellectual 310 points
Part Number: BOOSTXL-DRV8323RH
Other Parts Discussed in Thread: DRV8323R, DRV832X, LMR16006, MSP430F5529

Dear Community,

we want to use the BOOSTXL-DRV8323RH for driving a BLDC Motor and interface it to our own hardware.

We buy the H version of the evaluation board as we want to use a PWM signal for the speed control and a direction IO.

We want to use the ONE (1) PWM mode with using the hall sensor from motor to control the STATE[0..2] pin from chip.

As describe on page 30 from DRV8323R datasheet:

For the test we do have the following issues:

our signals (PWM and direction) are 5V TTL logic - on the datasheet it is written compatibility to 1.8V / 3.3V and 5V

On the evaluation board, it seem to be dedicated for 3.3V (the buck regulator is providing this 3.3V)

Is it possible to change the resistor: Rfb1 and Rfb2 to get 5V to supply the evaluation board?

For information: I need also 5V for our hall sensor as they need at least 5V for properly work.

In the datasheet I didn't fount any information about this resistors Rfb1 and Rfb2 and how to dimension them.

It seem for me that the FB pin should be 0.8V and so I will be able to dimension my resistor.

Do you have any application's note about it, that can help me? 

Many Thanks for your help.

Best Regards,

Xavier

 

 

  • 0
    TI__Expert 4650 points

    Hi Xavier,

    Section 8.3.5 of the DRV832x Datasheet states that for more information on the external Buck components, refer to the LMR16006 Simple Switcher Buck datasheet.

    If you change the Buck output for 5V instead of 3.3V, the EVM will be able to function but you will need to adjust the resistor dividers for the MODE, IDRIVE, VDS, and GAIN pins in order to set the correct values with a 5V reference.  

    Also, if you change the logic rail to 5V, you will no longer be able to interface the BOOSTXL-DRV8323RH EVM with the MSP430F5529 Launchpad.  

  • 0 in reply to Phil Beard
    Intellectual 310 points
    Hello Phil,

    many thanks for your help.

    I didn't see this information when I quickly read the datasheet.
    Concerning the compatibility with the Launchpad, thanks for your advice.
    On our own Hardware we do have external buffer from 3.3V to 5V so it will be safe with 5V supply.

    Best Regards,
    Xavier
  • 0 in reply to Xavier Queffelec
    Intellectual 310 points

    Hello Phil,

    I just made the change today and we can drive the motor. So it is looking good and we will adjust our feedback controller.

    Many Thanks for your help.

    Best Regards,

    Xavier

  • 0 in reply to Xavier Queffelec
    Intellectual 310 points

    Hello Phil,

    next week we will get our new stage. For the first test I want to reduce the available power from the evaluation board.

    Can I replace R6, R8 and R10 and use the equation 3 chapter 8.3.4 from the datasheet to adjust the maximum current?

    Many Thank for your help.

    Best Regards,

    Xavier

  • 0 in reply to Xavier Queffelec
    TI__Guru** 114905 points
    Hi Xavier,

    You can do this but there may be an easier method.

    As a first step, can you change to a higher gain? The EVM is set for 10V/V. By connecting the GAIN pin to 3.3V, the gain has been increased to 40V/V