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1mW laser driver and safety

Discussion in 'Electronic Design' started by Elektro, Feb 7, 2006.

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  1. Elektro

    Elektro Guest


    I need to find a laser driver circuit that can drive a laser diod
    emitting 1 mW. The laser will be driven with 70 kHz and 50% duty cycle
    (that is a peak of 2 mW).

    The laser power should be regulated with a DA-converter, preferably
    adjustable from 0 to about 1 mW.

    And I need some laser safety that shuts down the laser in case of
    malfunction. Maby some kind of watch dog timer circuit.

    So what options are there (preferably IC-circuits)?
  2. Mark X

    Mark X Guest

    Try alt.lasers
  3. Phil Hobbs

    Phil Hobbs Guest

    What wavelength? A 2 mW visible laser is class 2, so you might not need
    an interlock. As for the watchdog, you can use a retriggerable
    monostable, but you'd have to have something to drive it with, e.g. a
    spare MCU pin.


    Phil Hobbs
  4. Visible lasers 1 to 4.999 milliwatts are Class IIIa. Visible lasers .4
    microwatt to .999 milliwatt are Class II. At least in the USA - 21 CFR
    1040.10 and .11.

    Laser pointers legally sold in the USA are in one of these two classes -
    usually Class IIIa. (Britain limits those to Class II.) These do not
    legally require interlocks, keys, safety goggles, etc.

    The regulations beyond product labeling and certification kick in when
    you hit Class IIIb - 5 to 499.9 milliwatts. Although workplaces and
    schools can have their own safety rules for Class IIIa and Class II
    lasers, such as a requirement to wear goggles, etc.

    - Don Klipstein ()
  5. Phil Hobbs

    Phil Hobbs Guest

    Must have changed. I have a drawer full of 2 mW "Class 2" HeNe lasers.


    Phil Hobbs
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