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DRV2510-Q1: DRV2510-Q1

Ali Abdelsalam
Prodigy 50 points
Part Number: DRV2510-Q1

Here is a full explansion for my required voice coil function. I use a microcontroller which provides two inverted PWM signals to the driver. Here is the planed voice coil task/application listed in the following steps:

1. we need to start with the voice coil shaft inside the voice coil (position (A) / "mid-position or mid-stroke") for at for 4 seconds (for example)

2. After that we want to move the shaft forward to next position (B) and remain there for 2 seconds (for example)

3. While the shaft in position (B), we need to change in voice coil shaft force

4. We need to move from position A to B and from B to A in full speed

5. we will repeat this cycle of movements

our problem is the above steps but results are different that the expected, where the voice coil shaft canot be energized for the specified time in the above steps. just less than 1 second. i test also through its evaluation kit and i got same results of our circuit schematic. 

Any Help?. thanks in advance.

  • 0
    TI__Guru* 84915 points

    Hi, Ali,

    Welcome to E2E and thank you for your interest in our products!

    Regarding the output signal, do you have some captures about it during the specific time that the voice coil should be energized?

    Best regards,
    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    Prodigy 50 points

    Hello Luis,

    the above pictures are the drivers output which drive the voice coil motor.

    the above picture is the two input PWM signals at case the off state.

    the above picture is the two input PWM signals at case the ON state. one with 50% duty cycle and the other is 45%.

    - in the driver frequency settings, there just two options where 400KHz and 500KHz. could i change the frequency into any other value?

     Currently The Positive and Negative PWM control signals (Driver inputs) Frequency are 20kHz, we used the following PWM duty cycles for testing:
    1. Holding Voice coil at mid position;
    • Positive PWM  duty cycle is 99%
    • Negative PWM  duty cycle is 5%  
    • The Driver PWM output frequency is ~ 6 kHz
    •   Holding Voice coil forward (Constant Force);  
    • Positive PWM  duty cycle is 50%
    • Negative PWM  duty cycle is 45%  
    • The Driver PWM output frequency is ~ 400 kHz
    So, We want to know the relation between the input PWM control signals and  output PWM control signals and why there difference in the driver output frequency depending on the input pwm signal.
    Also, how can i control the force which is applied on the voice coil motor?.
    thanks in advance.
  • 0 in reply to Ali Abdelsalam
    TI__Guru* 84915 points

    Hi, Ali,

    Sorry, we lost your e2e thread since your previous verified answer closed the case. Thank you for open it again to continue the support.

    As you correctly mentioned, the output switching frequency is a configurable setting, but the driver switching frequency cannot be set to a value different to 400KHz or 500KHz. It's curious that you are getting this kind of output.

    The output signal, as mentioned in the 7.3.2 Pulse-Width Modulator (PWM) section of the datasheet, will be determined by the differential result of IN+ minus IN-. When IN+ is higher than IN-, the duty cycle of OUT+ is greater than 50% and the duty cycle of OUT- is lower than 50%. The opposite is true for negative differential inputs.

    The relation between the output duty cycle and the input level actually depends of the gain. When the differential input is 0V, the output duty cycle is 50%. For a 20dB gain, the maximum input level (which generates the maximum duty cycle ~98%) is 1Vrms. For 36dB, the maximum input level ~0.25Vrms. This is not a linear relation.

    Please let me know if you have additional questions or comments.

    Best regards,
    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    Prodigy 50 points

    Hello Luis,

    thanks for your replay.

    still i have a problem,  how can i control the force which is applied on the voice coil motor?.

    thanks in advance.

  • 0 in reply to Ali Abdelsalam
    TI__Guru* 84915 points

    Hi, Ali,

    In order to increase the voice coil motor force, you would need to have an input signal as close to 1Vrms as possible. If the motor force is not enough, you would need to incrase the VDD level also. Please notice that VDD level is directly related to the switching output level.

    Best regards,
    Luis Fernando Rodríguez S.