LED光源散热设计方法

1、邹静 （）GBU LED Lamps and SystemsJune 2010General Guide to the Heatsink Design for Fortimo modules ConfidentialGBU LED Lamps and Systems, June 20102Nice to know: Product leaflet; Design-in guide; Optical files; Catalog; Photometric files Certificates 3D file such as CAD fileConfidentialGBU LED Lamps an

2、d Systems, June 20103LED 模组会因为没有接散热器，过度受热而坏掉模组会因为没有接散热器，过度受热而坏掉吗？吗？ConfidentialGBU LED Lamps and Systems, June 20104LED 模组会因为没有接散热器，过度受热而坏掉模组会因为没有接散热器，过度受热而坏掉吗？吗？不会, 我们的模组有高温保护功能，一旦模组温度升到一定值，驱动器的输出电流会自动减小，这会阻止模组温度继续升高。ConfidentialGBU LED Lamps and Systems, June 2010 LED Performance issue? Tj必须保持在特定的

3、温度下，以免颜色飘移， 或者光通的改变。 5Why Bother?ConfidentialGBU LED Lamps and Systems, June 2010 LED Performance issue? Tj必须保持在特定的温度下，以免颜色飘移， 或者光通的改变。 Lifetime concern? 焊点经历一定次数冷热循环后（热胀冷缩的循环）会产生脱节。一般来说，焊点的温度越高，脱节前经历的冷热循环数越低。 6Why Bother?ConfidentialGBU LED Lamps and Systems, June 2010 Tc 对于模组来讲,只要 Tc保持在 650C or 55

4、0C, lifetime（B50L70）会在50000个小时左右。LLM模组由于具有CLO，所以lifetime不使用L70。 7Tc and LifetimeModuleTc life (0C)DLM65Lexel65SLM65LLM55Twistable55ConfidentialGBU LED Lamps and Systems, June 20108Special features Fortimo LED linearConfidentialGBU LED Lamps and Systems, June 20109 多少的功率（百分比）变成了热? ConfidentialGBU LED

5、 Lamps and Systems, June 201010How much power is turned into heat?一般来说一般来说, 有 remote phosphor的模组, 比如：2/3 的模组消耗的功率（系统功率 驱动器的功率）转变成了热。ConfidentialGBU LED Lamps and Systems, June 201011How much power is turned into heat?一般来说一般来说, 有 remote phosphor的模组, 比如：2/3 的模组消耗的功率（系统功率 驱动器的功率）转变成了热。RemotePhosphorTc

6、(C) POptical (W)Power module only WattWPEOpen5514.6532.844.71%4000K559.2432.828.17%3000K558.5732.826.13%1-45% = 55% 的功率转换成热!1-26% = 74% 的功率转换成热!转换成光的效率ConfidentialGBU LED Lamps and Systems, June 201012How much power is turned into heat?一般来说一般来说, 有 remote phosphor的模组, 比如：2/3 的模组消耗的功率（系统功率 驱动器的功率）转变成了

7、热。Remote PhosphorTc(C) submountPOptical (W)Power module only WattWPEOpen5514.6532.844.71%4000K559.2432.828.17%3000K558.5732.826.13%Side story!ConfidentialGBU LED Lamps and Systems, June 201013How to get rid of heat?被动散热主动散热Thermal management:Heat spreading （传热）（传热）: 把热传到一个更大的面积Heat sinking （散热）（散热）:

8、 通过convection（热对流）和radiation（ 热辐射）使热传到空气环境中。ConfidentialGBU LED Lamps and Systems, June 201014Thermal Management Heat spreading主要的传热机制（从模组到散热器）是主要的传热机制（从模组到散热器）是conduction（导热）;为了增加模组和散热器之间的热传导，一般要使用thermal interface materials (导热介质), 比如导热胶，或者导热膜，甚至导热管.散热器要用thermally conducting material（导热材料）（导热材料）金金

9、属是比较好的导热材料属是比较好的导热材料很很多情况下铝是首选，因为造工比较方便，价格也比较合适。多情况下铝是首选，因为造工比较方便，价格也比较合适。ConfidentialGBU LED Lamps and Systems, June 201015Thermal Management Heat sinking (Convection) 影响热对流的因素如下: 热对流系数 Pconv = hc* Aeff* (Tc-Tamb), 有效面积 热阻(Rth)如下: Rth= T/Pheat = 1/ (h* Aeff* ) 热功率 Tcase环境温度ConfidentialGBU LED Lamps

10、 and Systems, June 201016主动散热和被动散热的比较： ConfidentialGBU LED Lamps and Systems, June 201017Thermal management Heat sinking (Radiation) 热辐射的影响因素也可以写成如下： Prad = hr *Aeff* (Tc-Tamb), 热辐射系数 热辐射因素和emission coefficient(放热系数)成正比，而emission coefficient 和 表面处理有关：ConfidentialGBU LED Lamps and Systems, June 20101

11、8Thermal management Heat sinking (Radiation) 整个散热（热对流 + 热辐射）： Pheat = h * Aeff* (Tc-Tamb), 在我们模组的工作范围内，一般来说，热辐射在整个散热中占到 20% - 40% 左右，整个的传热系数在2-10之间。ConfidentialGBU LED Lamps and Systems, June 201019Heatsink ExamplesPassivePassivePassivePassiveActiveActiveConfidentialGBU LED Lamps and Systems, June 2

12、01020要考虑的因素： 用导热性能好的材料 铝是较好的选择 散热器的整个有效面积 Aeff = 1/ (h*Rth) 散热片的摆放位置 散热片之间的距离 散热片的长度 散热片的厚度 用放热系数较大的表面处理 铝一般用喷漆或者阳极 为了保证模组和散热器之间的热传导，要用导热介质ConfidentialGBU LED Lamps and Systems, June 201021Heatsink verification: Measuring Tc (with heatsink attached) The stabilization time for Tc can be between half

13、an hour up to 3 hours, which depends on the measurement environment. In general, it takes longer to stabilize in an enclosed environment, such as a simulated ceiling environment. Thermal couple can be used to measure Tc. Ensure good contact between the thermal couple and the module by taping (alumin

14、um tape) or applying a thin layer of quick drying glue and string relief Thermal couple has certain dimensions, so it is not recommended to put them between a module and a heat sink directly unless there is already a groove made on the heatsink. However, Tc can also be measured towards the side of t

15、he module, which of course will be a few degrees less than the temperature in the center.ConfidentialGBU LED Lamps and Systems, June 201022样例: 模拟的天花板环境中Tc的测量Tc等了1-2小时候才稳定； 一般来讲，在一个封闭的环境中，Tc要等比较长的时间才可以稳定下来ConfidentialGBU LED Lamps and Systems, June 201023样例: Tc 在敞开环境中的测量尽量避开空气流动比较大的地方！尽量避开空气流动比较大的地方！

16、+ 100C56.80CT_ambientConfidentialGBU LED Lamps and Systems, June 201024ConfidentialGBU LED Lamps and Systems, June 201025DLM: 在U型的边上测如果散热器安装在DLM的底部，边上的温度应该610C，只要可以基本保证Tc650CSimulation made with heatsink attached to the sides.ConfidentialGBU LED Lamps and Systems, June 201026散热器设计的流程 收集基本的一些信息，比如多少的

17、热功率，以及设计上的一些形状或者 大小的限制等等； 把以上信息输入到热学软件中,进行计算机模拟; 初步判断模拟结果对散热器设计进行修正; eg. Mould the first heatsink and do extensive real temperature testing. ConfidentialGBU LED Lamps and Systems, June 2010Measurement resultsTEST POINT#1(1800 24W/730) HS 1experimentextropolateextrapolateheat sink center (Tcase)5251.

18、461.4Ambient()25.62535Electrical power module (W)24Thermal power module (W)16Rth (K/Wth)1.7240mmx60mmx30mmWhat is h?ConfidentialGBU LED Lamps and Systems, June 201028What is h?A = 0.24x 0.03 x 9 x 2 = 0.13m2T = 52-25.6 = 26.40CP_heat = 16WP_heat = h * A * TSo h = 16/(0.13 * 26.4) = 4.6 W/m2 0C现在我们知道了h,下一步就要回到红色标示的公式去计算所需要的面积! 改进已有的散热器,再进行测量,直到达到需要的Tc.ConfidentialGBU LED Lamps and Systems, June 201029Heatsink VendorsBelow are a few links to professional heatsink providers: For passive cooling: AVC: htt