LED性能優(yōu)化

　　在過(guò)去的幾年中，現(xiàn)代LED的改進(jìn)功效，使工程師能夠使用較少的芯片在他們的照明燈具，以實(shí)現(xiàn)相同的光輸出作為舊的設(shè)計(jì)。關(guān)鍵的好處是降低成本和更簡(jiǎn)單的設(shè)計(jì)。今天的芯片增強(qiáng)魯棒性允許工程師采取的方法進(jìn)一步提高了當(dāng)前進(jìn)一步推動(dòng)個(gè)人LED光度和削減他們的數(shù)量甚至進(jìn)一步在一個(gè)給定的設(shè)計(jì)（見(jiàn)文章“LED亮度區(qū)最大化降低系統(tǒng)成本”）。

　　然而，盡管LED亮在更高的驅(qū)動(dòng)電流，增加亮度來(lái)降低成本的效果（籌碼在相對(duì)較低的電流，表現(xiàn)出最高的效能看高新區(qū)第“識(shí)別LED效率下降的原因）。這增加了功耗，并否定一些組件的成本降低的照明燈具的壽命的收益。功耗的增加也導(dǎo)致芯片運(yùn)行熱，縮短其壽命。

　　本文介紹了成本之間的權(quán)衡，設(shè)計(jì)簡(jiǎn)單，功耗和長(zhǎng)壽為一個(gè)給定的LED應(yīng)用程序運(yùn)行在高驅(qū)動(dòng)電流。

　　Finding the limit

　　In the early days of LEDs， when the fledgling technology delivered less light and was much more fragile than today， engineers were advised to limit the drive current to LEDs in order to maximize efficacy and prolong the life of the devices.

　　However， two decades of development （Figure 1） has seen LED efficacy soar and tolerance to the high-junction temperatures that result from increased drive current significantly increase. Many engineers question why low-drive currents are still necessary when such currents limit a chip’s output to only a fraction of its capability.