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Thread: The big TEC driver thread!

  1. #391
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    Quote Originally Posted by Eu1eOne View Post
    Perfect work !!! Iam searching for a TEC driver like that a long time. But theres one thing i miss. A Tec need more current for cooling than for heating. I think it would be better to control the current limit of heating and cooling individually. Iam also interested in 2 of these tec drivers.
    Current limiting is only necessary for TECs that are rated for less than 12V or less than 3 Amps the PID will take care of the rest. In order to get an equal response for heating and cooling 2 sets of PID parameters would be necessary but the response time is plenty fast enough as it is. The graphs you see above are the results of a rough setup and were not further tuned due to missing revisions of the PWM filter on this prototype build. As soon as the pre-series boards get here with these filter changes implemented, some more response graphs of TECs from 4W to 30W types will be posted.

    Here's a thread to a GB Interest poll http://www.photonlexicon.com/forums/...TEC-LD-drivers

  2. #392
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    I need a tec controller with more power than 3Amps. 48V @ 10A would be fine. I need a tec controller for my optical base plate.

  3. #393
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    Inspired by this thread I developed a highly stable TEC controller as Arduino shield. This is meant to stabilize laser diodes for holography, for show applications this would be overkill. Details are here: http://hololaser.kwaoo.me/electronic...duino-TEC.html

  4. #394
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    Looks nice

    Perhaps the xmega might be a better choice for faster PWM? or another nice option is the STM32F446 which would allow 12bit PWM at just shy of 90kHz, and the NUCLEO-F446RE has an Arduino form factor
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  5. #395
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    Quote Originally Posted by dave View Post
    Looks nice

    Perhaps the xmega might be a better choice for faster PWM? or another nice option is the STM32F446 which would allow 12bit PWM at just shy of 90kHz, and the NUCLEO-F446RE has an Arduino form factor
    Hello, yes I know but I wanted to keep it cheap and simple; the speed of the Uno is enough. What prevented me to look in more detail is that those all run on 3.3V which brings a ton of other inconveniences wth it.

  6. #396
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    Do you really need a controller? The TEC acts as a simple resistor. Unlike a diode, it will self limit its current depending on the voltage. I would suggest you mount the TECS and using a lab supply of if you do not have access to one with that kind of power capability, then try a couple of different voltage fixed supplies, narrow down the good enough, best voltage requirement and install that voltage directly to the TEC from a fixed power supply and you're done.

  7. #397
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    @"and you're done. " ......not quite ... might be best to add a cheap thermostat to protect the LD (just in case), for when the peltier fails.

    Cheers

  8. #398
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    Well, to achieve millikelvin stability some sort of feedback loop seems quite essential...

  9. #399
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    RedlumX,

    Just got around to reading through your write up on the controller. Nice work and an impressive result.

    Additional considerations for extremely stable LD operation would be:

    A hermetically sealed container for the diode should be built or better yet a vacuum chamber to isolate the diode from air currents and fluctuations in room temperature.

    A highly stable driver is necessary because all LDs shift their wavelength with drive current. This effect is more pronounced in the multimodes, but it is still a large effect in single modes compared to the effects of temperature at the mil-Kelvin level.

    Ultimately, a high dispersion spectrograph (specially built by you to greatly expand only the wavelength of interest) illuminating a linear CCD array with a feedback loop to the current and or temperature could help you to directly stabilize the wavelength.

  10. #400
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    Quote Originally Posted by planters View Post
    RedlumX,

    Just got around to reading through your write up on the controller. Nice work and an impressive result.

    Additional considerations for extremely stable LD operation would be:

    A hermetically sealed container for the diode should be built or better yet a vacuum chamber to isolate the diode from air currents and fluctuations in room temperature.

    A highly stable driver is necessary because all LDs shift their wavelength with drive current. This effect is more pronounced in the multimodes, but it is still a large effect in single modes compared to the effects of temperature at the mil-Kelvin level.

    Ultimately, a high dispersion spectrograph (specially built by you to greatly expand only the wavelength of interest) illuminating a linear CCD array with a feedback loop to the current and or temperature could help you to directly stabilize the wavelength.
    Perhaps you should check out the rest of his site Eric http://hololaser.kwaoo.me/argonlaser.html I think even you could learn a thing or two from Wolfgang Very cool site.
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