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Thread: The big TEC driver thread!

  1. #61
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    Default

    They look like really good value!
    This space for rent.

  2. #62
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    Quote Originally Posted by badger1666 View Post
    i have a die4chill but dont think its upto the job
    The die4chill is a pretty gutsy little driver. Choosing the right TEC's is the key tho..

    Can you squash 8 diodes down into a smaller area than 170 x 170? I reckon you could
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  3. #63
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    Default tecs

    Hi dave i could get 8 diodes into a tiny area but the plate i have them on also has 12 m,mounts pbs,wave plates,dichro,ect. All in one sealed unit, to keep all clean and temp stable , could you recomend 3 tecs i could use with my die4chill please
    When God said “Let there be light” he surely must have meant perfectly coherent light.

  4. #64
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    Hey Chris,

    You could always use a bigger TEC, and just keep the current below the die4chills max ( which I think is around 8A)

    I guess doing it this way would make the unit more stable mechanically as well
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  5. #65
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    Quote Originally Posted by dave View Post
    Hey Chris,

    You could always use a bigger TEC, and just keep the current below the die4chills max ( which I think is around 8A)

    I guess doing it this way would make the unit more stable mechanically as well
    thanks dave
    i will give the die4chill a go first

    so i could connect any tecs and just under drive them ??
    or do i pick tecs with lets say 3v input reqirement and use four in series
    for use on the die4chill at 12v ??

    or could you recomend four i could use please, as long as they are farely large in size
    to cope with the base plate fixed to them

    thanks
    When God said “Let there be light” he surely must have meant perfectly coherent light.

  6. #66
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    Mar 2008
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    Many direct injection LASER diodes (including recent 445nm and 635nm types) are quite insensitive to temperature fluctuations. A very simple circuit is all that is required for TEC stability at a reasonable temperature within the operating range. Here is the circuit I use in my 1W 445nm module.

    Code:
           +5V
            |
       -----------
       |         |
      NTC       TEC
      10k        | D
       |________|/    MOSFET
       |      G |\    IRF540L
      POT        | S
      10k        |
       |         |
       -----------
            |
           GND
    Choose a supply voltage close to (or even less than) the rated TEC voltage, because the difference will be dissipated as heat in the MOSFET. I used a +5V supply which is already present for the LASER diode in my 1W 445nm module. NTC is a 10k thermistor embedded in the diode mount for temperature feedback, and POT is a 10k potentiometer used to adjust the temperature setpoint. I used MOSFET IRF540L, but almost any N-channel MOSFET with logic level gate would be suitable. Because the MOSFET is used in linear mode, it must be attached to a heatsink to dissipate the power. I attached it to the base plate of my module next to the FlexMod P3 MOSFET. DPSS crystals may require a TEC controller with a faster or linear response, and a PWM controller can offer higher efficiency, but I found this circuit is ideal for my application.

    Click image for larger version. 

Name:	module_inside.jpg 
Views:	194 
Size:	88.3 KB 
ID:	22283

  7. #67
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    Default

    any NTC you could recommend? maybe a link off fleabay?

    this simple circuit is, to say the least, worth a go!
    thanks for sharing
    "its called character briggs..."

  8. #68
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    Quote Originally Posted by LaNeK779 View Post
    any NTC you could recommend? maybe a link off fleabay?
    You can use plain type:
    http://cgi.ebay.com/ws/eBayISAPI.dll...m=270607715964
    or crimp lug type:
    http://cgi.ebay.com/ws/eBayISAPI.dll...m=130350439685
    or bullet type:
    http://cgi.ebay.com/ws/eBayISAPI.dll...m=150536645571

    It does not matter, just choose the type which is easiest to attach to your diode mount.

    When you build the circuit, look at the "gate threshold" on your MOSFET data sheet, and measure the gate voltage with a multimeter. If you adjust the pot so that the gate voltage matches the gate threshold, the controller will keep the diode at room temperature. If you want the diode colder than room temperature, adjust the pot to increase the gate voltage slightly, wait for the new temperature to stabilize, then repeat the process if necessary.

  9. #69
    Join Date
    Oct 2010
    Location
    Athens, Greece
    Posts
    1,930

    Default

    i just got 10 mosfets for 6usd total NTCs are cheap too ( i had seen the ones you recomended but wanted to be sure)

    thanks a lot for your help and instructions.

    i will also try the tec controller that dnar suggested above, it also looks good value
    "its called character briggs..."

  10. #70
    Join Date
    Dec 2008
    Location
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    Default

    Quote Originally Posted by weartronics View Post
    Many direct injection LASER diodes (including recent 445nm and 635nm types) are quite insensitive to temperature fluctuations. A very simple circuit is all that is required for TEC stability at a reasonable temperature within the operating range. Here is the circuit I use in my 1W 445nm module.

    Code:
           +5V
            |
       -----------
       |         |
      NTC       TEC
      10k        | D
       |________|/    MOSFET
       |      G |\    IRF540L
      POT        | S
      10k        |
       |         |
       -----------
            |
           GND
    Choose a supply voltage close to (or even less than) the rated TEC voltage, because the difference will be dissipated as heat in the MOSFET. I used a +5V supply which is already present for the LASER diode in my 1W 445nm module. NTC is a 10k thermistor embedded in the diode mount for temperature feedback, and POT is a 10k potentiometer used to adjust the temperature setpoint. I used MOSFET IRF540L, but almost any N-channel MOSFET with logic level gate would be suitable. Because the MOSFET is used in linear mode, it must be attached to a heatsink to dissipate the power. I attached it to the base plate of my module next to the FlexMod P3 MOSFET. DPSS crystals may require a TEC controller with a faster or linear response, and a PWM controller can offer higher efficiency, but I found this circuit is ideal for my application.
    Click image for larger version. 

Name:	module_inside.jpg 
Views:	194 
Size:	88.3 KB 
ID:	22283
    Just built one of these for a giggle, works great - thank you
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