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LM3464: spec question

Walsh
Intellectual 950 points
Part Number: LM3464

Hi,

I will make a LED driver design for 64 channel 8 seires LED and current is 1.5Amax per channel. I am evaluating LM3464.

Does LM3464 could support 1.5A?(per channel or combine 2 channels)

How much is channel to channel accuracy?

Is there other recommendation?

Thanks,

  • 0
    TI__Mastermind 28655 points

    Hello,

    Maximum LED current per sting is limited by the external parts chosen, the current sense resistors and the MOSFETs used.  SOA and power dissipation for the MOSFETs needs to be checked over the operating range you plan on using it including any fault conditions or variances in LED stack voltages.

    The EVM has a graph showing a typical four channel version current regulation accuracy channel to channel over varying operating temperature.  I'm looking to see if I can find worst case input offset voltage to the current regulator as well.  The current sense resistor plays a part in the accuracy as well as layout (voltage drops on traces).

    Thanks,

  • 0
    TI__Mastermind 28655 points
    Hello,

    Follow-up; The channels will regulate to +/- 5 mV of the 200 mV or +/- 2.5% at 25 degrees Celsius. This includes reference and input offset of the current regulator, the current sense resistor is not part of this as it is external.

    Thanks,
  • 0 in reply to Irwin Nederbragt
    Intellectual 950 points

    Thanks, Irwin.

    That mean LM3464 could support LED current per string greater than 1A? Why it's shown 1A max. in the datasheet? Is it just an example? 

  • 0 in reply to Walsh
    TI__Mastermind 28655 points

    Hello,

    Since the MOSFETs and current sense resistor are external it can be used beyond one amp, again, a lot has to be taken into consideration for the MOSFET, SOA, power dissipation for example.  Figure 19 is the only reference to a range of current but it's just for showing resistor values for a range.

    Thanks,


  • 0 in reply to Irwin Nederbragt
    Intellectual 950 points
    Hi Irwin,

    Got it, Thanks.