FlexMod N2 Laser diode drivers have now arrived :)

'Good news everyone!' The FlexMod drivers have arrived and I will ship the outstanding orders shortly. Thank you everyone who had to wait. This is a high speed laser diode modulator capable of driving high and low current diodes for direct injection lasers and DPSS modules.

Specifications:

* Power input: 5-12VDC
* Analog Input: 0-12V max, usually you set to 5V full range
* TTL input: 0-5V Off-On
* Gain setting: 11 turn pot with 2 ranges 0-1A, 0-6A output.
* Bias setting: 11 turn pot range 0-2A output
* Dimensions: 31x21.5mm


http://hacylon.case.edu/laser/FlexModN2/modu.jpg

Available here

Cool! More current!

Oh cool, a newer model? It was worth the wait then.

nice same price?

and can you explain the differences?

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Originally Posted by thesk8nmidget

nice same price?

and can you explain the differences?

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Hi, yes same price, also if you have any unused V1 drivers you can exchange them up to V2 for free. The differences are:

- lower dropout voltage so that 5A 1.8V diodes can be driven with a 5V supply
- input over-voltage protection for low range (up to 2A)
- up to 6A drive with proper heatsinking
- gold plated solder contacts

Nice!

I was asking myself, if it is possible to power up two (660nm) diodes with the same driver, and if it would be a good idea?
I was thinking to put them in series (as I'm already doing that with power LEDs), so if one diode die one day there won't be double current on the other (current limiting driver...)

Seriously... This happened to me here.

What is the price?

FlexMod 1 Laser Modulator Circuit ($35 ea)

Quote:

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Originally Posted by Admin

Seriously... This happened to me here.

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Haha worked as intended :)

Quote:

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I was asking myself, if it is possible to power up two (660nm) diodes with the same driver, and if it would be a good idea?

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Hi, I'll post here what I posted in the V1 thread:

Hi, yes you can run many diodes of the same type from one driver, just stay within the current limitations of the driver (6A max)

Each diode is slightly different, so to even out the current draw between the diodes when they are in parallel, you should put a (thick) metal film resistor in series with each diode. This is true for driving parallel diodes no matter which driver you use.

Let's say you are making a super red and want to use as many red diodes as possible, and you want the max current to be 300mA to each diode, and the lasing threshold is 75mA. Choose a resistor so that it drops about 10% of the diode voltage at the idle current, or 0.3V at 75mA: 4 ohms. Then calculate its voltage drop and power disipation at full power: 4 ohms*300mA = 1.2V; 1.2V*300mA= 0.36W

So, for an array of open can diodes you should use 4 ohm, 1/2W or 1W resistors in series with each diode. Maximum number of diodes on one driver is 8A/300mA = 25 diodes.

Minimum power supply voltage for the driver would be 3V (diode voltage) + 1.2V (resistor voltage) + 2.0V (Driver requirement when delivering 8A (0.25V per amp)) = 6.2V. If you are only driving 2 diodes in parallel then a supply voltage of 5V is fine.

Finally, your diodes should be of the same make and model, and thermally coupled so they stay close to the same temperature, and electrically isolated. They should be connected to the same size heatsink block and with the same length and type of wire.

Typically if a red diode dies, it dies of optical failure and so will maintain virtually the same output voltage drop, saving the other diode it he pair. However if it fails open circuit via some mechanical abuse (I have never seen this happen after a diode was installed in a mount, but have seen it happen AS a diode was being installed, so test!) then the other diode will take double the current.