• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 496 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TLC59711: Noisy and too low voltage ouput of TLC59711

Vincent Paratte
Prodigy 170 points
Part Number: TLC59711

Hello,

I am trying to drive a brushless DC motor with an APF27 but I do not have enough PWM output. Therefore, I tried to use the TLC59711. I used exactly the same design as the one presented in the datasheet (with a 3.3 kOhm resistor from iref to ground, a 1 muF from vreg to ground and Vcc to a power supply of 8 V).
The output seems to work correctly as I can vary the PWM value but the shape is not a perfect square (there is an important RC behaviour) and the voltage amplitude is to low (500 mV peak to peak and it does not change while varying the power supply).

Moreover, I am trying to create a sinwave signal (with variation of PWM) but when I integrate the signal (RC filter), I observe that my sinus is very noisy (not the expected step function when I zoom in).


I tried with 5 different TLC59711 and the behaviour is allways exactly the same.

Does anyone has an idea of how to resolve the problem?

Vincent

  • 0
    TI__Genius 14295 points
    Hi, Vincent,

    To get more information, can you send me the schematic and OUT scope shot to analyze the problem?

    You can also test the OUT waveform using resistor as load instead of the motor to see the shape.

    It's mostly because the inductive load slow down the rising and falling edge.

    Thanks.

    Regards,
    Kenneth