Difference between LED driver and LD driver

I'm afraid I know little about 'Buckpups' and not much more about these new high powered LEDs.

But I want to hear what others say on this...

John.

I am assuming LD is laser diode, and that laser diodes might get hot so a feedback circuit element is useful. Another device that requires temperature feedback is a (good quality) battery charger. However constant current LED drivers are very common and incredibly versatile. I haven't come across one that needed anything more.

I use the BuckPuck in all my design and my next lamp will use the QuadPuck 4016 (4 buckpuck controlled by DMX).

While you need to control the temperature of your HB LEDs with appropriate heatsink (and sometime airflow), you don't usualy need to modulate the power based on the temperature like you would with a laser diode. The buckpuck can handle about 20 watts each.

However, if you still need to control the temperature by modulating the power, you can use the "E" type of Buckpuck (3021-E) and create a little circuit for a feedback loop with a thermistor. Look in the datasheet, there's examples for controlling a Buckpuck with external resistance or PWM.

Thank you very much for the replies...I guess the main reason maybe because the Buckpuck driver is very well designed, so no additonal circuits are needed? Also, LEDs do not need to be operated at specified temperature and current to keep the wavelength and width?

LED needs to be operated within specified temperature and current. But this is rarely achieved through a feedback loop with a temperature sensor modulating the current. Unless you're planning to overdrive the LEDs big time, you can easily cool them using heatsink while running the LEDs at their max current. If you drive them at constant current (100% PWM), temperature should stabilize after an hour. With heatsink and forced airflow, I can keep at 35 Celsius a dense LED array (a mix of Luxeon and Norlux Led) running at full power (60 watt) with 4 buckpuck.

Unless your application needs a very precise and stable wavelength, heat is not the biggest issue when you run LEDs at their max rated current. The datasheet of LED will usually provide data on the wavelength shift that occurs with temperature variation, you'll know how stable the temperature will need to be. I'm not sure that the possible variation with temperature is greater than the variation you will find between different "bin" of the same LED model by some manufacturer. So if you require a precise wavelength, be careful in selecting the right "bin" for your needs, because you can have differences up to +/- 30nm between bins.

Also keep in mind that some color of LEDs are more stable than others and some model are less sensitive to temperature, like the K2 from Luxeon that can be driven at higher temperature than most HB LED.