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Original question:

DRV2604: DRV2604 Stopping Waveform Playback

DRV2604L: PWM input mode, Stopping Waveform output signal

Yusuke Mukuno
Expert 7395 points
Part Number: DRV2604L

HI Expert 

This is similar question to following session.

My customer is using the PWM input mode for IN/TRIG pin configuration.

MODE = 3: PWM input and analog input

N_PWM_ANALOG = 0: PWM Input

The customer found the issue about not stop output signal even if IN/TRIG go down to low.

The time between IN/TRIG low and actual output stop timing  is not constant. it is stop by EN low in all cases. 

I found similar waveform in the datasheet as below,

Left is not stopped output signal.

Right can stop output signal by EN low.

Could you please let me know the reason of  not stop output signal? Is it due to the braking signal? (from above E2E session)

What parameters will the length of time between IN/TRIG low and actual output stop timing be depend on?

Also, Should we control EN for output stop? or   Should we control STANDBY bit for output stop? (< from above E2E session)

Initial setting

Address              Value

0x01 0x0
0x16 0x57
0x17 0x6d
0x18 0x8
0x19 0x8b
0x1a 0xb9
0x1b 0x1a
0x1c 0xf5
0x1d 0x84
0x03 0x0
0x01 0x3

Thanks

Muk

  • 0
    TI__Guru* 84915 points

    Hi, Mukuno-san,

    Our team will take a look at this information and will provide an answer as soon as possible.

    Best regards,
    Luis Fernando Rodríguez S.

  • 0
    TI__Mastermind 20685 points

    Hello, Mukuno-san,


    Does your customer notice a 180 degree phase shift on the outputs when IN/TRIG goes low indicating breaking? If so then this is why the waveform continues after IN/TRIG goes low. this could be verified by setting register 0x1a = 0xF9 which will disable breaking. and then observe if the waveform continues after IN/TRIG goes low.


    In this case the back emf related to the velocity of the LRA will be the parameter controlling how long the output is driven after IN/TRIG goes low.


    The STANDBY bit can be used to immediately stop the device from driving the outputs at all, however if what the customer sees is braking, then I would not recommend this as the braking is generally desired.

    what application is this device being used?

    Regards,

    Arthur Brown

  • 0 in reply to Arthur Brown
    TI__Expert 7395 points

    Hi Brown-san,

    ------

    Q1 . Could you please review the registers setting? Is it no problem?

    ------

    Customer need braking function from their system requirements. So, they need to understand about the braking function, braking time (period) and root cause of this issue. Then, They have to adjust the delay between  IN/TRIG=L and EN=L(or STANDBY off).

    This issue is occurred over different periods of time between IN/TRIG=L and EN=L.

    Customer's software is programed the 1s delay between IN/TRIG=L and EN=L.

    Each waveforms are below,

    case1 : keep 130ms output after IN/TRIG=L.

    case2 : keep 30ms output after IN/TRIG=L.

    case3 : keep 1s output after IN/TRIG=L.

    * Above waveforms are an example, they have many cases.

    Q2. If the root cause is braking operation, is it possible that braking time is over different periods by tests, like above waveforms?

    ------

    Please refer the zoom-in waveforms after IN/TRIG turned Low, below,

    Q3. Is it braking waveform?

    Q4. Could you please let me know the reason of this waveform?

           Also, if it is braking waveform, Could you please let me know the braking function mechanism?

    Q5. What parameters are the braking "time(period)" depend on? Is it depend on the actuator parameters?

    Q6. If they change the braking gain in the register 0x1a(FB_BRAKE_FACTOR[2:0]), how does it affect the waveform?

    ------

    Q7. Please let me know the outputs state when device will be STANBY mode or EN=L?

    ------

    The customer would like to get your answer as soon as possible. please help us.

    Thanks

    Muk

  • 0 in reply to Yusuke Mukuno
    TI__Guru* 84915 points

    Hi, Mukuno-san,

    We will take a look at these questions and will come back with our feedback as soon as possible.

    Best regards,
    Luis Fernando Rodríguez S.

  • 0 in reply to Yusuke Mukuno
    TI__Mastermind 20685 points

    Hi, Mukuno-san,

    I will close the thread for now to continue support via email

    Regards,

    Arthur Brown

  • 0 in reply to Arthur Brown
    TI__Expert 7395 points

    Thanks, Brown-san