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DRV8308EVM: Sine mode and Fault alert setting problems

Pearl Lin
Prodigy 310 points
Part Number: DRV8308EVM
Other Parts Discussed in Thread: DRV8308

DRV8303 is using in the DJ turntable, which care about noise and some special operating condition.

Our customer has three question about the DRV8308 GUI modification,

 

1. The customer testing with PWM MODE, setting SPEEDTH = 25%, MINSPD = 255, 70%DUTY to start up.

It took about 2.1sec. to enter the sine control mode, how could we set the mode to enter sine control when started vs waiting for 2.1 sec

2.When the motor is turning, and user need the function of using hand to scratch the disk with not enter the fault condition and stop turning.

The test result is the Scratch caused our DRV8308 entering the fault protection and stop.

I read the 0X2A, and try writing to 0, but it didn’t work, and the default reading is not  0X18 also.

How could I fix this?

 

3.DO we have the document about how to modify the Hall sensor location in BLDC to optimize the Performance and startup speed?

  • 0
    TI__Guru** 114905 points

    Hi Pearl,

    Pearl Lin said:

    1. The customer testing with PWM MODE, setting SPEEDTH = 25%, MINSPD = 255, 70%DUTY to start up.

    It took about 2.1sec. to enter the sine control mode, how could we set the mode to enter sine control when started vs waiting for 2.1 sec

    What are the register settings used?

    What settings have been tried to minimize the time to enter sine mode (SPDREVS, MINSPD, and SPEEDTH)?

    Pearl Lin said:

    2.When the motor is turning, and user need the function of using hand to scratch the disk with not enter the fault condition and stop turning.

    The test result is the Scratch caused our DRV8308 entering the fault protection and stop.

    I read the 0X2A, and try writing to 0, but it didn’t work, and the default reading is not  0X18 also.

    How could I fix this?

    What value was read from 0x2A?

    Pearl Lin said:
    3.DO we have the document about how to modify the Hall sensor location in BLDC to optimize the Performance and startup speed?

    This post should help:

    e2e.ti.com/.../1285151

  • 0 in reply to Rick Duncan
    TI__Prodigy 310 points

    1.( SPDREVS, MINSPD, and SPEEDTH)=(3,255,25%), and MOD120= 3907

    2. What value was read from 0x2A? 0X2A=58
  • 0 in reply to Pearl Lin
    TI__Guru** 114905 points
    Hi Pearl,

    Thank you for the information.

    While we may be able to determine a method to speed the startup, it could be difficult to avoid the stall condition when scratching the disk.

    Has the customer considered remaining in 120 mode? This would allow the hall sensors to keep track of the position when scratching the disk.
  • 0 in reply to Rick Duncan
    TI__Prodigy 310 points

    Hi Duncan,

    1. Could we let the motor start up in 120 sine mode directly?The 180 mode would cause the disk with some audible noise.

    2. They would like to stay in 120 mode, and we would like to know if the stall fault could be disable, than the fault would not be alerted when scratch.
    and the fault couldn't be rewritten also. do you have any idea about this?

    Thank you.

  • 0 in reply to Pearl Lin
    TI__Guru** 114905 points
    Hi Pearl,

    1. Set BASIC = 1 and ENSINE = 0 to remain in 3 Hall mode. This may help some for start up, and should help with scratching the disk.

    2. Setting LRTIME = 11 and FGSEL = 01 should help. LRTIME = 11 requires 10 seconds of no transitions to set the stall fault. FGSEL = increases the number of pulses on FG.