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LM3401: Efficiency at Vin=5V, 1 series LED 700mA

Franz Schellhase
Expert 3605 points
Part Number: LM3401

Hi,

can you tell me why the efficiency curve for LM3401 for 1 series LED (700mA) doesn't go down to Vin=5V but the 1A measurement does? Can you tell me the efficiency at that point?

Thank you,

Franz

  • 0
    TI__Mastermind 28655 points

    Hello Franz,

    If you look at the EVM it shows which LEDs are used.  The 1 series LED at 700 mA is actually a 7.0V forward voltage the 1 series LED at 1A is 4.5V forward voltage, see table 2 of the EVM.  This is an older design so using number of LEDs doesn't make sense for new design since the Vf of the data in the datasheet and EVM is, most likely, higher.  Using the forward voltage for comparison would be fine.

    Best Regards,