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LM3466

Other Parts Discussed in Thread: LM3466

Good morning,
We are currently using this IC for our LED lamps.
Currently the Rsens equals 0,5ohm (700mA), if I apply 900mA something happens to the circuit?
It could heat up too much to the integrated internal mosfet?
The problem may have led?
I can not change the RSES

  • Hello,

    How are you using this? Do you have multiple LM3466s? Are you feeding this with a current source? The LM3466 is a current sharing IC that equalizes current between multiple strings powered by a current source.

    The LM3466 should not have a problem with a 0.5 ohm current sense resistor and 900 mA of current. The resistor needs to be capable of the higher power dissipation.

    Thanks,
  • good morning,
    We use 4 lm3466s and input we have a constant current power supply equal to 2.9A, 700mA for each lm3466.
    Changing power supply, from 2.9A to 3.6A was found, after about 5000 hours, an imbalance of the branches and consequently a blackening of the LEDs.
    Not all of the plate LEDs have had this problem.
    I was wondering if those 900mA could break the mosfet of lm3466 or create some problem to 'IC
  • Hello,

    If the LM3466 has enough heatsink it should be fine.  If not it can thermally limit.  I wouldn't recommend running the LM3466 near thermal limit just as I wouldn't recommend running the LEDs at high temperature either.  It will shorten life.  Something else to consider is if there is a fault in one of the strings the remaining three will share the current.  This means the current in those strings will jump to 1.2 amps.  Have you tried replacing the LEDs to see if the LM3466 ICs still function correct?  What do you mean by an imbalance of the LEDs?  Current or something else?

    Thanks,

  • good morning,
    the LED plate is of aluminum so it is difficult to desolder the LEDs.
    So from what you tell me, if there is a proper heat dissipation of the component, there should be no problems.
    my question is: What is the Rsens if this integrated balance any current passing through the LED?
    Thanks
  • Hello,

    I'm not sure what this question is asking: "What is the Rsens if this integrated balance any current passing through the LED?"

    The LM3466 tries to balance the current by sensing the voltage at the SEN pin. If the SEN resistor is 0.5 ohm at 700 mA the voltage at the SEN pin will be 350 mV. If the balanced current is 900 mA the voltage at SEN will be 450 mV. If there are four LM3466s running at 900 mA and one string opens the new SEN voltage on the three remaining strings will be 600 mV.

    Thanks,