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Thread: 445nm diode with flexmod p3 and laserbug goes only to 380mA

  1. #1
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    Default 445nm diode with flexmod p3 and laserbug goes only to 380mA

    i connected everything according to the manual but when i turn up the gain the max i get is 380mA measured at the diode + and -, not sure if i am doing something wrong but any help would be great.

  2. #2
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    How many volts are you supplying the FM with?

    Have you applied a full 5V to the mod line?

    Are you sure you've adjusted the output and not he bias?

  3. #3
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    I use 24V on the flexmod P3, G and +24.1V

    On the mod line are 4.75V
    I am adjusting the pot which is located on the far side of the transistor... i didn't touch the bias yet...

  4. #4
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    If I'm reading what you wrote right......

    Set the threshold (bias) first and then the output. Adjust the min current first, then with +5 on the mod line, adjust max current.


    Setup and operation:
    Preliminary setup:
    1) Locate a 5 to 24V regulated (preferably) power supply. If the power supply is not regulated (typical of wall-warts),
    measure its output voltage to verify that it is at or below 24V. Maintain a closed interlock throughout setup.
    2) Solder lead wires of the appropriate length to the board connection holes, but to not connect the load yet.
    3) Attach the transistor to a heat-sink (necessary for modulation currents over 250mA or power supplies over 5.5V). The
    included heatsink is adequate for currents up to 500mA with a 5V supply. If the heatsink gets too hot to touch during
    operation, switch to a larger one.
    Current Adjustment:
    4) Connect the output wires to your multi-meter, set to Amps mode.
    5) Short the modulation input wires together and power on the driver, you should get a reading on your multi-meter of 50-
    150mA. Adjust 0Bias until you reach the desired standby current. Clockwise turns the current up, counterclockwise turns
    it down.
    6) Un-short the modulation input wires and while maintaining power to the driver apply 5V to the Mod+ input and adjust
    gain to the maximum desired current. A clockwise adjustment increases current.
    Final Connection:
    7) Power off the driver and temporarily short the output. Connect the output wires using the shortest length possible (no
    longer than 3 feet total length) to the load. Observe proper polarity. (Inner + pad connects to diode anode, outer – pad
    connects to cathode and is grounded.)
    8) Connect the modulation input to your DAC or modulation test apparatus. Make sure that no wires are crossed, and the
    board is not contacting any electrically conductive surface.
    9) Power on and test your application!
    Last edited by mophead; 01-11-2011 at 17:25.

  5. #5
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    i will follow this and report back if anything has changed...

  6. #6
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    Don't use 24V in that setup, there's no reason to, it's very wasteful. Use a 5.5V or 6V power supply. Can your supply provide enough current? a 1A 24V supply would be pretty beefy.

  7. #7
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    i have a PSU 5.15V which powers my 532nm laser, its a 120Watt so should be OK. I could use that no problem, since i use the 24V for the scanners, so doesn't matter where to power comes from. I will continue my test with the 5V then and report back if i still have any problems...

  8. #8
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    The issue with driving a single 445 via P3 with 24V is the Flexmod will have to drop approx 20V and thus generate a fair amount of heat. A good heatsink will be required too.

    At 1A, the Flexmod must dissipate 20V x 1A = 20W of heat!!!

    For a single 445, you need around 8-9V minimum in my experience with the P3.
    This space for rent.

  9. #9
    Lased is offline THIS USER WAS CLUEBYFOURED
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    Quote Originally Posted by dnar View Post
    For a single 445, you need around 8-9V minimum in my experience with the P3.
    You would think that greater than 6V was necessary based on the specs, but I have three 445nm diodes all powered by Flexmod P3s. I'm using three 5V 2A supplies to power the flexmods.. I measured the output on each power supply, and they are all well below 5.1V but no less than 5.03V. They all run perfectly.. I'm not sure why or how, but I've had no trouble at all getting and maintaining full power output. The flexmods all stay completely cool. No heat generated at all as far as I can tell.. Also, I'm running only one diode per driver.

    I actually use these PSUs since they also provide 12V for my fans: http://cgi.ebay.com/I-T-E-AC-005W-PO...item5641fbbaed

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    Quote Originally Posted by Lased View Post
    You would think that greater than 6V was necessary based on the specs, but I have three 445nm diodes all powered by Flexmod P3s. I'm using three 5V 2A supplies to power the flexmods.. I measured the output on each power supply, and they are all well below 5.1V but no less than 5.03V. They all run perfectly.. I'm not sure why or how, but I've had no trouble at all getting and maintaining full power output. The flexmods all stay completely cool. No heat generated at all as far as I can tell.. Also, I'm running only one diode per driver.

    I actually use these PSUs since they also provide 12V for my fans: http://cgi.ebay.com/I-T-E-AC-005W-PO...item5641fbbaed
    When you actually experiment with 445 and P3, you find the sensitivity and supply rejection is better at 8-9V that at 6V.
    This space for rent.

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