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Original question:

LM3464A how to disable the unused channels?

LM3464A: About the LED drive power supply

Timsen
Expert 1660 points
Part Number: LM3464A
Other Parts Discussed in Thread: LM3466, LM3464, LM3409, TPS92515

Dear all:

       Please find an existing LED drive power supply project:

Input characteristics: 1. Input voltage: 120v-277vac frequency: 47-63hz; 2.2. Harmonic (THD):THD 15% (120-277vac);3. The PF: 0.95 PF or less (120-277 - vac)

Output characteristics: 1. Two groups of outputs, the output power of each group is about 15W Pout=15W, the total output power is P =2Pout=15*2=30W;2. During normal operation, the lamp voltage is Vout= 42-43v, and each group has independent open circuit and short circuit protection functions;3. The output is constant current, and the output current of each group is Iout= 340-360ma, and the center value is Iout=350mA;4. Dimming: 0-10v dimming. When the DC Source is adjusted to "0v", the light shall be turned off, and the light shall not flicker;5. Efficiency: over 90% output efficiency of the whole machine (120-277vac)

Q1:Can this scheme be realized with LM3464A?LM3464A can support 0-10v dimming. Should the light be turned off when the DC Source is adjusted to "0v" and there should be no flicker?

Q2:Is there a cheaper, more appropriate device proposal?

  • Please find an existing LED drive power supply project

  • 0
    TI__Mastermind 28655 points
    Hello Timsen,

    Is your 120V-277V power source a current source with two channels of 350 mA? If so the LM3464 is not the correct part. You may want to look at the LM3466 for that, it is a current share device, one per string. How many LED strings per power source output? If it is one per current source you don't need the LM3464 or LM3466.

    LM3464 is a DHC (uses an adjustable voltage output source that the LM3464 can control).
    LM3466 controls a single LED channel, it requires use of at least two to current share between LED strings.

    0-10 dimming can be done with the thermal pin on the LM3464 though I need to know if this is the correct device. 0-10V dimming with the LM3466 is limited in range and probably not good enough for 5% analog dimming.

    Using a buck converter from a voltage source will be more efficient with high voltage LED strings, The TPS92515, LM3409 as well as other buck converters would work for this. At this power level getting above 90% with a two stage solution is not trival.

    It would be helpful to know what the power source is intended to drive, two channels going to how many strings of LEDs, etc.

    Best Regards,

    Irwin
  • 0 in reply to Irwin Nederbragt
    TI__Mastermind 28655 points
    Hello Timsen,

    I haven’t heard back from you, I’m assuming you were able to resolve your issue.
    If not, just post a reply below (or create a new thread if the thread has locked due to time-out)

    Best Regards,