LM3464 dimming

Tom Saluzzo

Other Parts Discussed in Thread: LM3464

The LM3464 is being setup so that we provide a PWM dim signal that is 20kHz and we also dim thru the thermal pin at 40kHz. Will concurrently dimming at these frequencies (we run the PWM and thermal dimming both at the same time in certain instances) cause any issues?

over 12 years ago

0 LK Wong over 11 years ago

TI__Prodigy 180 points

We expect the input to the thermal pin is an analog signal instead of a PWM.

0 Tom Saluzzo over 11 years ago in reply to LK Wong

Expert 1280 points

I don't understand your answer. Please explain.

0 Guilherme Borba over 11 years ago in reply to Tom Saluzzo

TI__Intellectual 1910 points

Tom,

You said that you dim through the thermal pin at 40kHz, which sounds like it is a PWM input. I believe that the input to this pin should be an NTC (negative temperature coefficient) thermal sensor, which is an analog signal.

LK,

If they do have an analog signal in the thermal pin (pin 3) and a PWM signal in the DIM signal (pin 2) simultaneously, could this result in any issues?

Regards,

Gui

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LM3464 dimming