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LM3409

Abdolhossein Kangani
Prodigy 90 points
Other Parts Discussed in Thread: LM3409

Hello,

We use the LM3409 LED driver in EN pin PWM dimming for 4 LEDs. On EN pin is a PWM signal 0...10 kHz. In the range of 0...80Hz switched LM3409 on after a delay, so after turn on need driver longer time to return.

 

Turns EN pin only OUTPUT FET on and off, or even internally others logic?

 

Can LM3409 LED driver wired so that this process in the low frequency range does not happen( no external parallel FET dimming)?

Best Regards

  • 0
    TI__Mastermind 25296 points

    I'm not pretty sure I got what your problem is, but yes, EN pin enables internal logic as well, not only the GDRV.

    Since the PWM signal is normally a low frequency one, the little delay in EN effects are normally negligible.

    While for "high" frequency PWM the external FET is reccomanded for a proper dimming effect.

    Vincenzo