LM3466: PWM possible?

JP Potgieter

Part Number: LM3466
Other Parts Discussed in Thread: LM3464

Good Day,

I saw a thread where it was mentioned that PWM dimming wasn not possible with the LM3466, but no reason given. Is it because the chip gets "turned off" ot the low of the PWM.

Is there any way around this? giving the chip external power supply? Or is only analogue dimming possible with the LM3466?

Any help will be appreciated.

Kind Regards,

over 5 years ago

0 Irwin Nederbragt over 5 years ago

TI__Mastermind 28655 points

Hello JP,

If you can PWM at a very low frequency it will basically just turn off and on, see figure 9. It has to go through a power on sequence and balancing of the LED strings. This part was not intended to be PWM dimmed, it has fault circuitry and current balancing circuitry that are not compatible with this. The LM3464 is design for PWM dimming though it is four channel.

Best Regards,

0 JP Potgieter over 5 years ago in reply to Irwin Nederbragt

Prodigy 30 points

Thank you for the quick reply and the recemendation. We looking for an IC that can take constant current like the LM3464 but that will be able to accept PWM, do you know of an IC that has that capabilities.

0 Irwin Nederbragt over 5 years ago in reply to JP Potgieter

TI__Mastermind 28655 points

Hello,

The LM3464 can take PWM inputs.

Best Regards,

0 JP Potgieter over 5 years ago in reply to Irwin Nederbragt

Prodigy 30 points

Hey,

Sorry for not being clear, I understand it can take PWM, but only a voltage source, or can I connect a constant current driver to it?

0 Irwin Nederbragt over 5 years ago in reply to JP Potgieter

TI__Mastermind 28655 points

Hello,

Sorry, didn't noticed the constant current part but only the LM3464 part. Unfortunately no. You could convert the PWM to analog and get some dimming capability on the LM3466 but there is a limit so not a very wide dimming range.

Best Regards,

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LM3466: PWM possible?