Pulsed Led Ccs

Discussion in 'General Electronics Chat' started by haha11, Aug 29, 2014.

  1. haha11

    Thread Starter New Member

    Dec 10, 2008
    9
    0
    i have used a fast rise fall square waver transistor circuit to get the
    pulses like 30Hz
    one led shows the pulses

    SMd LED5050 x 2 PCS is the main lighting device
    for test purposes


    fed to the normal CCS (constant current source)

    --background
    * i came to know that LEDS can be pulsed with 2x or more current
    pulses like 100hz to 4Mhz are used in driver chips

    So made this amateure combo circuit .


    Question :
    I want to make the led take 150% current from rated 20mA ,
    is the combo working as pulsed oscillator


    Canwe avoid the CCS
    and safely pulse the LED with small changes

    is it good to pulse with 150% power for SMD 5050 leds
    .
     
  2. ian field

    Distinguished Member

    Oct 27, 2012
    4,415
    784
    IIRC: Sharp have published some useful appnotes on pulse/duty cycle drive for LEDs
     
  3. haha11

    Thread Starter New Member

    Dec 10, 2008
    9
    0
    any links....for some specific info on SMD5050

    SMD 5050 led is good one procured from industrial supply
    today i pulsed them with 159mA current 2 modules in parallel


    they seem to light pretty bright..no heating for 20min test

    not sure if it may degrade life?
     
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