• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 29 subscribers
  • Views 373 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

Original question:

TMS320F28035: Control of Dual 3-Phase Motor

DRV8301: Control of Dual 3-Phase Motor

jianyuan liu
Intellectual 380 points
Part Number: DRV8301

I’ve read the schematics of drv8301. And find out the spi signals are isolated.

Why should do these ? Does the high-voltage power supply PVDD will affect the control spi signal ？

(And I know that ,the spi signals are not directly connect to the drv8301, but it’s not important.)

And, in my case, I’ll use FPGA to provide the PWM signals, then use the PWM to drive the DRV8301.

Is here should be isolated with FPGA (PWM) and DRV8301 ?

 

I’ve read the schematics of drv8301. And find out the spi signals are isolated.

Why should do these ? Does the high-voltage power supply PVDD will affect the control spi signal ？

(And I know that ,the spi signals are not directly connect to the drv8301, but it’s not important.)

And, in my case, I’ll use FPGA to provide the PWM signals, then use the PWM to drive the DRV8301.

Is here should be isolated with FPGA (PWM) and DRV8301 ?

  • 0
    TI__Intellectual 2585 points

    Hi Jianyuan,

    The isolation is only to protect the host PC in the case of a short/damage on the EVM. The SPI signal on the DRV8301 supports either 5V or 3.3V operation (depending on what voltage is supplied to VDD_SPI), so as long as your FPGA supports 3.3V or 5V input, it should be fine to connect your FPGA directly to the DRV8301 SPI signals.

    Thanks,
    Garrett

  • 0 in reply to Garrett Walker
    Intellectual 380 points

    Hi,Walker.

    Thank you very much for your reply.

    And in my case, we’ll drive the PWM signals directly from the FPGA to DRV8301 also.

    It’s same to the SPI signals from FPGA to DRV8301.

    So, I think it’s safely according to your viewpoint.

     

    And, on other hand.

    I found that some shunt current measurement schemes have the isolation function

    It’s may be an isolated sensor, an isolated amplifier or an isolated ADC.

    But there is no isolated circuit in the TI’s demo.

    Is it the resistive shunt is too small? and it is under the safety voltage.

    Or do you have a reference circuit for the isolation ?

    Thanks a lot !

  • 0 in reply to jianyuan liu
    TI__Intellectual 2585 points

    Hi Jianyuan,

    The DRV8301 integrates two low-side current sense amplifiers, which do not require isolation, as a low-side CSA is GND-referenced.

    For example, with the 2 mohm shunt resistor on the EVM, even at 100 amps, you'd only see 200mV at the amplifier inputs, so isolation is not needed.

    However, in-line or high-side current sensing architectures may require isolated amplifiers.

    Thanks,
    Garrett

  • 0 in reply to Garrett Walker
    Intellectual 380 points

    i got it, thank you very musch,and happy new year !