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LM3431: LM3431/92 Application Question

Part Number: LM3431
Other Parts Discussed in Thread: LM3421, LM3492, TPS92515

Hello TI,

May I know TI LED driver have similar NCV78763 device? Looks LM3431/92 has same boost-buck(linear) of topology.
Could you help us comments for below question?
1. LM3431/92 linear current sink benefit compare 78763 switch current source.
2. How LM3421/92 solved pitfalls of parallel LED arrays.

  • Hello Kuo,

    Let me look into this a bit more tomorrow and I will let you know. Are you more interested in the LM3431 (3 channel) or LM3492 (2 channel)?

    Thanks,

    Clint

  • Hi Cliniton,

    Yes. I hope foundly replace NCV78763.
    And depends on application to decide LM3431/92.

    Regards,
    John
  • Hello John,

    I am not sure they compare very well directly to the NCV device. That is a two stage with a boost followed by two high-side current sense buck regulators (similar to the TPS92515). The LM3431/92 are boost (or SEPIC for buck-boost) followed by linear regulators that adjust the output voltage to minimize losses in the linear elements. The linear current regulation allows for very low ripple and fast PWM dimming if required and is likely to be a bit more accurate than a buck.

    So the best approach would probably be for you to let me know what specs you need so I could make a recommendation. Could you provide your input voltage range, LED string voltage and number of strings, LED string currents, and any analog or PWM dimming requirements you might have? Thanks.

    Regards,

    Clint