Power LED Driver

Discussion in 'The Projects Forum' started by 4beowulf7, Jul 25, 2015.

  1. 4beowulf7

    Thread Starter New Member

    Jul 25, 2015
    20
    5
    Hi guys!
    This circuit is simple yet powers up 1-5W IR LEDs with constant current. Any idea to make a pulsed LED driver?
     
  2. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,282
    1,233
    Just pull the gate of the FET to ground with another small transistor.
     
  3. ScottWang

    Moderator

    Aug 23, 2012
    4,853
    767
    If you want to use it as pwm control then you can using a 555 pwm, and the output connect to the (+) of U2 LM358.
     
  4. 4beowulf7

    Thread Starter New Member

    Jul 25, 2015
    20
    5
    Thanks!
     
  5. RodneyB

    Active Member

    Apr 28, 2012
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    What is the wattage of each of the resistors shown in your drawing
     
  6. 4beowulf7

    Thread Starter New Member

    Jul 25, 2015
    20
    5
    For Figs. 2-3-4, I used a 1Ohm 2W resistor as R3. Rest were 0.25W.
    For the 0.33 Ohm resistor in Fig. 1, I don't remember the Wattage. It was about 3cm long ceramic resistor.
     
  7. ian field

    Distinguished Member

    Oct 27, 2012
    4,413
    782
    With the op-amp versions, a resistor could be inserted between the inverting input and the current sensing resistor, that would allow an added transistor to pull the inverting input high - sending the op-amp output low.
     
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