• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 692 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.

LM3463: Common anode LED driver

Michael Lehmann56
Prodigy 20 points
Part Number: LM3463
Other Parts Discussed in Thread: TPS92691, LM3445, LM3444, TPS92692

Hi all

Im looking for a LED driver to operate an application with a single high power LED. The LED current is 10A and the LED voltage between 2.8V and 3.8V.
The LED is a common anode LED which means the anode is connected to housing / cooling pad which will be on earth potential. For the whole system, the best case would be if the led anode potentail is on GND.

My favourite driver would be the LM3434 or LM3433. Unfortunately, the state of both of them is livebuy, so no option for my application. Because of the common anode, i cant find a alternative yet.

One option now is to use a driver like the LM3463. Is it possible to operate that driver in the voltage range above? Can i maybe move the whole potential down so Vtrail is 0V and GND (of the driver) will be e.g - 3.3V? I would as well add external FET driver if the internal driver can not handle fets above 6Amps.

Are there some other alternatives to the LM3434 and is there a special reason why no TI does not recommend any replacement?

Regards

  • 0
    TI__Mastermind 28655 points
    Hello,

    LM3463 isn't meant for that, it's a linear multi-channel current regulator. Can you provide a voltage where the high input is tied to ground and the low input is a negative voltage? There are a few parts that would work that way.

    Example, a 12 volt supply, the positive rail is GND and the negative rail is -12V. TPS92691, TPS92692, LM3444 and LM3445 would work for that.

    Regards,
  • 0 in reply to Irwin Nederbragt
    Prodigy 20 points

    Hi

    Ideal case would be +/- 12V. The LED has to be operated with continious 10A.
    The TPS92691 and TPS92692 do not have a fixed anode voltage what i see from the datasheet. As well I am not sure if the gate driver supports a 10A mosfet. Corret me if i am wrong.

    For the LM3444 and LM3445, if the Vbuck would be GND, is it still possible to dim the LED (without the triac)?

    Regards and thank you

    Michael

  • 0 in reply to Michael Lehmann56
    TI__Mastermind 28655 points
    Hello Michael,

    LM3444 and LM3445 can be dimmed without a triac by adjusting the FILTER pin. Note that LM3444 and LM3445 regulate peak current so it will become non-linear dimming when it goes discontinuous. A lot of our led drivers are for lower power so the gate drives will not support large gate charge at high frequencies. MOSFETs have improved over time so finding a MOSFET to drive 10A may work fine with most of these parts especially at lower rated VDS voltage.

    Regards,