To Buck or not to Buck

[jjspike]

Hey all,

I will be using BBE's drivers in my build and my red section will consist of 2 diodes in series - 5V requirement. Optimal driver input would be 7V - 5V for diodes and 2V for the driver. I was considering using a buck step down regulator to provide the 7V from my 12V power supply as I did not want to generate excessive heat at the driver. For those of you with practical experience in this area, would this be a good way of tackling this issue or should I run the 12V in and deal with some heat? I've used regulators in many projects in the past however I'm not sure about running a driver, which is a regulator, via another regulator. Some of these buck step down modules are really cheap and this does not give me a warm and fuzzy.


Thank you!

[jors]

Which diodes? specs?

[-bart-]

No problem whatsoever. I have a rgb projector with a 12v supply that runs the fan directly. Then I use 3 separate buckregulators to supply each driver with the exact voltage to reduce dissipation.

As a matter of fact, many highend drivers have an integrated buck, such as the picodrive, and the driver that edison uses for his modules and projectors, among others.

I never had a cheap LM2596 style regulator fail on me, though I wish I could say the same of the fancy DC-DC converters.

[jjspike]

I'm using the Oclaro 700mW diodes. I took a closer look a the documentation for the driver and noticed that it provided a formula for determining dissipation. Assuming my diodes are in series and accoutning for the 2V driver overhead, being 5V over in terms of supply voltage should still put me in a safe range for the driver based on the formula. Unfortunately the excess heat dissipated will run into the baseplate and this may not be desired. Seeing that I would not have to sink as much the heat into the baseplate if using the buck, it might be a better solution in terms of thermal management. I suppose I'll have to perform some tests to see how much heat ends up in the baseplate and go from there. Comments are welcome as I am still on the ground floor with my build.

Thank you!