The big TEC driver thread!

Quote:

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Originally Posted by LaNeK779

are these any good??

http://cgi.ebay.com/ws/eBayISAPI.dll...#ht_5393wt_905

http://cgi.ebay.com/ws/eBayISAPI.dll...#ht_4038wt_957

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They look like really good value!

Quote:

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Originally Posted by badger1666

i have a die4chill but dont think its upto the job

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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 :)

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

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 :)

Quote:

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Originally Posted by dave

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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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

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.

Attachment 22283

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

this simple circuit is, to say the least, worth a go!
thanks for sharing

Quote:

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Originally Posted by LaNeK779

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

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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.

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

Quote:

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Originally Posted by weartronics

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.
Attachment 22283

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Just built one of these for a giggle, works great - thank you :)