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Square waveform input Vin TL2575HV-05

Flavien Roux
Prodigy 50 points
Other Parts Discussed in Thread: TL2575HV-05

Hi everybody,

I need to do this schematic for my board:

It's possible to have square waveform at my input Vin (0 to 24V). I have any others solutions for supplie my DC/DC regulator. So my question is : what is the reaction of the TL2575HV-05 if i have a low frequence ? Can it accepte a square waveform in input ? What's about time life ? What's the effect on the output ??

I didn't found any informations in the documentation

www.ti.com/.../tl2575hv-05-q1

Except this but there are no informations with this timing.

Thx for reading

Best Regards


Flavien.

  • 0
    TI__Mastermind 24975 points
    Hello Flavien,

    I don't believe that there should be any damage to the device as the device will just be turning on and off, but I would not expect that the device would be regulating properly.

    The device requires a DC input to be able to regulate, so with a square wave the device will be regulating and then not regulating in rapid succession based on the duty cycle and frequency of the square wave.

    I would expect there to be a lot of noise on the output of the device because of this on/off cycling of the device.
    Are you using a PWM to vary the brighness of the LEDs and then trying to regulate from this voltage? If you have a source for a 24V PWM, do you not have a 24V DC supply to put on the input of the TL2575HV.

    Best,
    Michael
  • 0 in reply to Michael J Schultis
    Prodigy 50 points

    Hi Michael ! Think you very much for your best answer !!


    For your questions;

    "Are you using a PWM to vary the brighness of the LEDs and then trying to regulate from this voltage?"


    No. Befor my inputs there are switches bring the 24V, so it's like a waveform but I can't change switches.

    I use the DC/DC converter for supply LEDs and take less power that is I would use 24v supply. So if there are noise at the output, I don't think that will be a problem.


    Maybe I can improove the schematic with the On/Off input ??

    Thinks a lot again Michael.

    (Sorry if my Enlish is not perfect, it is early here)


    Flavien

     

  • 0 in reply to Flavien Roux
    TI__Mastermind 24975 points
    Flavien,

    I don't believe the ON/OFF input will help you in this scenario.
    With an input square wave, I am concerned that the output may be varying widely in its output.
    The best case would be to have as close to a DC input to the device as possible, but without being able to do this, I would suggest setting this circuit up and testing it to see what the output voltage looks like.

    Best,
    Michael
  • 0 in reply to Michael J Schultis
    Prodigy 50 points
    Michael,

    Thanks a lot for your answers, after reflection, the probalility to have a waveform in input will be low. So we can suppose that the supply will be DC because I have some LED always on.

    thx a lot again ! You are awsome.

    Flavien.
  • 0 in reply to Flavien Roux
    TI__Mastermind 24975 points
    Flavien,

    Very happy to help. Please feel free to post other questions you have on these forums. We are constantly monitoring these to help answer any questions you may have.

    Best,
    Michael