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DRV2605: Setting for ERM by external PWM input

Part Number: DRV2605

Hi,

Our customer is considering to drive ERM by external PWM input.

Please tell me which registers must be set.

I think that the following procedure is necessary to make it an external PWM.

1. Power on

2. Turn EN to high

3. STANDBY bit = 0

     At this point the device status is active

4. MODE[2:0] = 3

5. N_PWM_ANALOG = 1

   When PWM is input at this point, the motor turns.

  I think that they can check whether the motor moves at this point excepting control.

  Is it correct?

Next step, I want to know the registers necessary for controlling ERM.

Are there any registers that must be changed from the default?

Best regards,

Tomoaki Yoshida

  • Hey Tomoaki,

    I think that with this part you cannot use the external PWM signal. I think that you can only control the duty cycle of the PWM signal (that is then generated inside of the IC) with the input pins. For that mode, the setting you wrote would be correct.

    I am not 100% sure about it, so I will confirm it with a colleague as well and then get back to you.

    Best regards,
    Marko
  • Hi Marko-san,

    Thank you for your reply.

    I'm sorry, there was a mistake in what I wrote.

     fault :5. N_PWM_ANALOG = 1

     correct: 5. N_PWM_ANALOG = 0

    My customers want to run in PWM and open loop mode.

    They intend to set registers as follows.

     0x1A[7] = 0 : ERM(default)

     0x1D[5] = 1 : open loop

     0x1D[1] = 0 : PWM(default)

    Other registers are still default.

    I think that other setting is necessary in particular for external PWM mode.

    Please let me know if there are registers to set.

    Best regards,

    Tomoaki Yoshida

  • Hey Tomoaki-san,

    I clarified this issue. If you want to use this part in open loop mode for an ERM with PWM external input, you should set registers as following (as you wrote in your 2nd post):

    0x1A[7] = 0 : ERM(default)
    0x1D[5] = 1 : open loop
    0x1D[1] = 0 : PWM (N_PWM_ANALOG = 0)

    Best regards,
    Marko