文：法比奥·萨诺圭涅
by Fabio Sanguine
本期介绍了近些年被特别关注的大功率 LED 的性能，其中包括其效率、耐热性、驱动电流以及其它新性能:
This article introduces the performance of PowerLEDs, that including their efficiency, thermal resistance, driver current as well as their other new features :
Lm/W
流明瓦（Lm/W）是光效的单位，是指光源的光通量与其消耗的电功率之比，其得到了重要的改善。现已有超过150lm/W 的 LED。这个效率的获得是芯片制造技术和其尺寸改善的结果。这使得在极低的 Vf 值（正向电压）时可以获得高光通量。众所周知，LED 电压下降可以降低能耗。和前几年不同，如今我们已经有 Vf 值（正向电压）低于3V（图1）， 电流为350mA 的 LED。
Lm/W
There has been a significant improvement in efficiency, in terms of flux emitted in relation to Wattage consumption. LEDs with efficiencies of over 150 lm/W are now available. Such levels of efficiency are possible due to improved technology in relation to chip production and size. This has enabled high flux levels and minimal levels of Vf (Forward Voltage). As we are already aware, a reduction in LED voltage leads to reduced energy consumption. Unlike a few years ago, we now have LEDs with forward voltages, expressed as 350mA, of less than 3V. (Picture 1)
耐热性
基于对热管理的重要意义，各 LED 生产商也开始投资大功率 LED。该热管理取决于产品的预期寿命（L70）、LED 流明瓦的比值、成本、色调等。现在可以购买 Rth 低于5°C/W 的产品，既有单芯片也有多芯片，而在不久前该参数还是8-10°C /W（图2）。
Thermal resistance
The various LED manufacturers have also invested in this area due to its significant effect on the system’s thermal management. Such management depends on the product’s estimated lifetime (L70), the lm/W ratio of the final LED matrix, cost, colour tone, etc. You can now buy, in both single and multi-chip versions, devices with a Rth well below 5°C/W, which until not long ago were only available in 8-10° C/W. (Picture 2)
驱动电流（If）
关于驱动电流，目前已经可以购买到3A 的 LED。由于采用先进创新科技，可以使 LED 达到这样高的电流，这样可以显著降低光通量输出成本（lm/Eu 或 lm/$）， 而同时并没有忽略该系统的热管理（图3）。
Current (If)
With regard to the maximum driver current, it is now possible to purchase LEDs that can be operated up to 3A. Thanks to innovative technologies, which allow the LED to be driven up to such current, it has been possible to significantly reduce the ratio of flux output to cost (lm/Eur or lm/$), while not neglecting the system’s thermal management. (Picture 3)
多芯片
近几年，市场出现一些基于采用多芯片封装的新产品。这些产品来自不同的生产商，具有不同性能。实际上，有一些 LED 采用便于使用的容器，这样的容器可以插入封装内部，用简单的螺丝固定。这些方案的特点是：在能耗相同的情况下，获得更高光通量。现在，这些产品效率值（lm/W）低于单芯片产品。可以看到，在这些产品中，无论是光通量还是效率都得到了很大改善，使用这些产品可以配备在光通量、显色性、颜色、散色性等方面都很好的零件。实际中有多芯片技术的 LED，3step MacAdams 椭圆装置能运用多芯片 LED 技术，其显色指数（CRI）超过90%，（图4）。
Multichip
In recent years, new products using of multiple chips within the same product have been put on the market. Several manufacturers offering a variety of types and performances sell such products. We can now easy to use LEDs, which simply screw into the unit. These products tend to have excellent flux levels alongside equally efficient consumption levels. Currently, the levels of efficiency (lm/W) of these products are less than the single-chip products. Significant improvements, both in terms of flow and efficiency mean that by using these products it is possible to produce high-performance devices in terms of flow, size, colour rendering and size of colour dispersal. The 3-step MacAdams ellipse offers multichip LED technology with a CRI of over 90% and linear colour spaces (Picture 4).
