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DRV10983: Start up time of DRV10983

Jason Fan
Intellectual 1705 points
Part Number: DRV10983

Hi Supporting team:

                     I found there is a fixed 330mS time slot between the wake up mode (Vreg on) to the align mode , please check the plot below ,

  channel 1: customer system signal (regardless)    channel 2 : Speed pin (analog speed )     channel3 : Vreg     channel4: U phase

  t2 is the time that drv10983 wake up , t3 is the time that entering the align mode.

 Question 1 :  I need to clarify the time between t2 to t3 , what's the 10983 doing during this time ?

 Question 2 :  If possible , can we tune the speed by the voltage  on the speed pin during this time , does it take effect?  During this time , could the  internal ADC on the speed pin work and update the speed information ?

 

                  

  • 0
    TI__Mastermind 18900 points

    Hey Jason,

    Since I don’t have access to the current waveform at the voltages on at least two of the phases, I’ll have to answer your questions based on some assumptions.

     Question 1 :  I need to clarify the time between t2 to t3 , what's the 10983 doing during this time ?

    The time from t2 to t3 looks like the period of alignment. If the customer is using Align and go for initial position then current is run through V and W for the align time. This could be the case since we can’t see current or the voltage of the other phases. The align time value can be changed to be shortened but it must be long enough for the current to stabilize before continuing on in the startup process.

     Question 2 :  If possible , can we tune the speed by the voltage  on the speed pin during this time , does it take effect?  During this time , could the  internal ADC on the speed pin work and update the speed information ?

    Usually our device goes through 3 steps when starting up: Initial position (Align and go or IPD), open loop (spins according to start up settings which is independent of the exact speed), and closed loop (which takes the speed command into consideration and adjusts RPM accordingly). As a result, changing the open loop start up settings for a faster start up time will help get into closed loop faster.

    Hope this helps,

    -Cole

  • 0 in reply to Cole Macias
    TI__Intellectual 1705 points

    Hi  Cole:

                Thanks for your prompt reply.

               Today I captured more waveform with U,V,W phase voltage from customer's side for your reference.  Please look at below

               Channel1: Vreg    Channel2 : U phase  Channel3 : V phase   Channel4: W phase

               The t3 which we are talking about is seems not the alignment time , it is in ahead of the alignment.

    Question 1: So I am still wondering what the time it is . As my consumption , is it  might including eeprom loading , internal ADC setting up , ISD detection and so on?

    Question 2:  Customer didn't want to make the start up time shorter , they just wonder if it could take effect if they tune the speed by the speed pin during t3?

    Question 3:   After the Vreg power up , does the DRV10983 wake up from the sleep mode ?

               Hope for your reply !

  • 0 in reply to Jason Fan
    TI__Mastermind 18900 points

    Hey Jason,

    Thanks for getting the scope shots. I aplogize that I misspoke about align and go. As you can see, U and W are energized for the align function (t4) so you are correct.

    Question 1: So I am still wondering what the time it is . As my consumption , is it  might including eeprom loading , internal ADC setting up , ISD detection and so on?

    Yes, t3 is the time it takes for start up out of standby/sleep mode and you’re exactly right that the device is taking time to calibrate the ADC, etc.

    Question 2:  Customer didn't want to make the start up time shorter , they just wonder if it could take effect if they tune the speed by the speed pin during t3?

    The voltage of the speed pin before entering closed loop operation only needs to be above the Analog voltage-to-exit sleep/standby parameter listed in the datasheet. To reiterate, the voltage on the speed pin does not matter until the transition from open to closed loop. As a result, they could set the speed voltage to whatever value they want before that time.

    Question 3:   After the Vreg power up , does the DRV10983 wake up from the sleep mode ?

    Yes, Vreg turning on is usually the first sign that the device is fully out of sleep/standby mode.

    Best,

    -Cole

  • 0 in reply to Cole Macias
    TI__Intellectual 1705 points

    Hi. Cole

               Thanks for your comments.

                 For the questions 2, can I think the drv10983 will implement the last speed setting on the speed pin before the close loop , right?

  • 0 in reply to Jason Fan
    TI__Mastermind 18900 points

    Hey Jason,

    No problem!

    Yes, the DRV10983 will implement the last speed setting on the speed pin right before closed loop operation. With that said, you can change the speed setting any time during closed loop and you should see the motor speed increase and decrease accordingly.

    Best,

    -Cole