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LM3555 Flash current

PAN-M
Mastermind 8375 points
Other Parts Discussed in Thread: LM3553

Hi

Our customer need 180mA flash current (20mA Torch) setting, but this device set limiting minimum 200mA.
Can we lower current setting by external circuit?

ex.

Regards,
PAN-M

  • 0
    TI__Intellectual 1940 points

    Hello,

    At first glance, this external circuit looks like it could work.  This is something I have never tried.  I would worry about temperate variations causing the LED current accuracy as well as the part to part accuracy to become reduced.  As the temperature increases the LED VF will drop and make the current in the LEDs increase.  

    Plus, this external load is going to cause a pretty large hit to the solution efficiency (throwing away 10% of the current).

    Can the customer use a parallel LED architecture?  If so, a part like the LM3646 could be an option.  

    Greg Lubarsky

  • 0 in reply to Greg Lubarsky
    Mastermind 8375 points

    Thank you for answer.

    Our customer cannot change to parallel LED because serial LED is module.
    Do you have any other idea?

    PAN-M

  • 0 in reply to Greg Lubarsky
    Mastermind 8375 points

    Hi

    Can LM3553  set 180mA LED flash current?

    Regards,
    PAN-M