welight
Well-Known Member
Thermal Resistance is a critical aspect of led design. The pillar design used in these has become a standard even for star boards to assist in minimal resistance between the junction and the heatsink. The reality is within nanoseconds of firing a led it will hit 25C hence the move to 85C binning, this is a temperature that reflects real world conditions and why most datasheets show a lumen hit between the two. Cree's latest XHP leds like XHP70 provide long term summary data now based on 105 and 125C, they want you to run these new generation leds hotter, why, because you can reduce fixture cost by using smaller heatsinks. Heat remains the enemy and Thermal resistance remains critical in total design consideration
Cheers
Mark
Cheers
Mark