led电路的比较

　　led电路的比较

　　近年来，发光二极管（LED）已成为传统光源的一种可行的替代品。长寿命、高效率、体积小、反应时间短的优点使白炽灯泡的数量不断增加。一个市场，这种变化已经成为最明显的是汽车，在使用LED背光仪表盘和开关不仅，而且在中央高位刹车灯（CHMSL）外部照明，后组合灯（RCL），转向信号灯和水坑照明。

　　尽管寿命长的LED故障率低，汽车可以发现，有时，在他们失败的LED高位刹车灯。这通常是由于有缺陷的电路设计，其中LED灯是可以过。考虑到这个假设，编写了这个应用说明：识别、描述和评论串行和矩阵电路中的LED行为和故障模式。

　　Failure modes of LEDs

　　Ultimately there are two possible failure modes for LEDs： light degradation and total failure. Light degradation occurs when the emitted light falls to 50 percent of its’ initial value. This is due simply to aging of the LED. The second failure mode， total failure， is caused by an open contact between the Chip and the lead frame， between the Chip and the bond wire or between the bond wire and the lead frame. The reason for this failure is an overheating of the LED past the glass point of the resin. This leads to a softening of the resin， and when the resin material cools and becomes hard once again， mechanical forces on the bond wire cause an open contact.