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DRV8313: about DRV8313 and DRV8312

user6237567
Prodigy 30 points
Part Number: DRV8313
Other Parts Discussed in Thread: DRV8312, , TMS320F28034, TMS320F28035

Rise/fall time: DRV8313 150nsec → DRV8312 14nsec
Propagation delay time (from inputting PWM signal to IN until actually outputting signal from OUT)
tpd on 500nsec max → DRV8312 38nsec
tpd off 475nsec max → DRV8312 38nsec
Dead time
DRV8313 90nsec → DRV8312 6nsec
DRV8313 is about 10 times slower than the above.

Compared with the DRV8313 and DRV8312, is there a difference in the timing when UVW three-phase drive is performed after the PWM output from the control microcomputer is input?

Is there any deviation in the timing of sampling the phase current?

  • 0
    TI__Mastermind 21805 points

    Hello!

    DRV8313 has a longer delay time as well as rise & fall time compared to DRV8312.

    The delay time will result in a longer delay from the microcontroler PWM command to the output, and so when sampling current you may need to take this into account by adding some delay into your ADC sampling time.

    The longer rise and fall times will result in a higher minimum pulse width achievable from your control scheme. DRV8312 will be able to drive <100ns pulse widths (i.e. 1% minimum duty cycle on a 100kHz PWM) while DRV8313 will only be able to achieve ~350ns pulse width as a minimum (i.e. 3.5% minimum duty cycle on a 100kHz PWM). If your system has a lower PWM frequency or does not have an aggressive minimum PWM duty cycle requirement, this may not be an issue.

    A longer rise time & fall time also results in a slightly lower average voltage applied to the motor, at extreme cases (high PWM frequency) it may limit the maximum speed.

    Thanks,

    Matt

  • 0 in reply to Matt Hein
    Prodigy 30 points

    Hello Matt,

    Thank you for your advise.

    The purpose of this question is to investigate the cause of the timing, which U, V, and W phases and the Hall sensor edge at the time on DRV8312-C2-KIT, is changed on our ASSY as shown in the attached file. The major difference from the DRV8312-C2-KIT is the change from DRV8312 to DRV8313. Other than that, it is almost the same. The software source code has not been changed except for the port assignment change.
    Please let me know, if you find any advise from these information.

    Thank you and best regards,

    TaisukeE2E question(933694).xlsx

  • 0 in reply to user6237567
    TI__Mastermind 21805 points

    Hello Taisuke,

    Thanks for these plots.

    It looks like phases have a different order:

    • Phase U of DRV8312-kit --> Phase W of DRV8313 board: Hall U rising edge corresponds with peak of U waveform on DRV8312-kit and peak of W waveform on DRV8313 board
    • Phase V of DRV8312-kit --> Phase U of DRV8313 board: Hall V rising edge corresponds with peak of V waveform on DRV8312-kit and peak of WU waveform on DRV8313 board
    • Phase W of DRV8312-kit --> Phase V of DRV8313 board: Hall W rising edge corresponds with peak of W waveform on DRV8312-kit and peak of V waveform on DRV8313 board

    Was there a change in firmware on the TMS320F28034 versus TMS320F28035? Was there a swap in PWM resources to phases U, V, & W? It looks like by changing the assignments for each phase you can help fix this.

    Thanks,

    Matt

  • 0 in reply to Matt Hein
    Prodigy 30 points

    Hello Matt,

    Thank you for your information.

    And sorry for late reply.

    We changed using port as following.
    DRV8312-kit
     U － PWM1A
     V － PWM2A
     W － PWM3A
    Our ASSY
     U － PWM1A
     V － PWM2B
     W － PWM3A
    There is not a swap in PWM resources to phases U,V,W.
    We don't know why the timing, which U, V, and W phases and the Hall sensor edge at the time on DRV8312-C2-KIT, is changed on our ASSY.
    Is it possible that this issue is caused by difference of DRV8313 and DRV8312?
    Thank you and best regards,
    Taisuke
  • 0 in reply to user6237567
    TI__Mastermind 21805 points

    Hello Taisuke,

    How about the Hall sensors: was there any change in order or connection? Or connection from the DRV8313 (OUT1/2/3) to the motor windings?

    Both DRV8313 & DRV8312 have independent control of each phase, so there is no channel switching within the device (IN1 --> OUT1, IN2 --> OUT2, IN3 --> OUT3)

    Thanks,

    Matt