[经验]

为汽车LED前灯解决方案选择拓扑

2018-10-15 08:47:55

1511 安森美 OEM

使用LED作为前照灯具有多种优势。
不仅减轻重量和减少二氧化碳排放量，而且还可以更好地控制点亮的区域，以及各种形状，使汽车OEM易于识别。
Pixel Light解决方案或Matrix Beam避免使用远光灯来眩目迎面而来，同时优化驾驶员的视野，从而提高所有道路使用者的安全性。
Matrix Beam有两种主要拓扑：并行驱动和串行驱动。
图1：串行拓扑。
每根串都有多个LED串联，允许更高的电压。
图2：并行拓扑。
每个LED都有一个电流吸收器，通过公共阳极缓解LED的冷却。
并联驱动的主要优点是LED具有共用阳极引脚，在非常特殊的情况下，LED可以帮助从LED芯片到散热器的热传输，即多个LED芯片位于同一LED封装中。
然而，这种偶然的优势并不能弥补与并联驱动相关的许多缺点。
该解决方案每个LED需要一个电流源。
在考虑完整系统的同时，由于此拓扑所需的线性电流吸收器中的功率损耗增加，因此并联驱动所需的散热器更大。
串行拓扑的优势超过了LED冷却的成本：每串一个电流源，并且当LED处于活动状态时，并联开关不会耗散额外的电力。
所有LED都有固有的电流匹配，无需选择具有匹配正向电压的LED。
该拓扑允许使用更高的电压和更少的转换损耗。
串行驱动器提供更高的模块性，与像素光解决方案以及非像素光兼容。
图3：NCV78763：用于汽车前照灯的功率镇流器和双LED驱动器第2代/ 1.6A
使用下面的评论部分分享您的意见！
您如何看待并行驱动器与串行驱动器？
您认为哪种解决方案在市场上推进？

以上来自于谷歌翻译

以下为原文

Using LEDs for front lighting provides multiple advantages. Not only weight reduction and CO2 savings, but also better control of the areas to light up, as well as various shapes which make the car OEM easy to recognize. Pixel Light solutions or Matrix Beam avoid glaring oncoming drivers while using the high beam to optimize the driver’s visibility and thus increasing the safety for all road users.
There are two main topologies for Matrix Beam: Parallel Drive and Serial Drive.

Figure 1: Serial Topology. Every string has multiple LEDs in series allowing higher voltages.

Figure 2: Parallel Topology. Every single LED has a current sink, easing the cooling of the LEDs through a common anode.

The main benefit of parallel driving is the LEDs have a common anode pin, which helps the heat transport from the LED-chip to the heatsink in the very special case that multiple LED-chips are in the same LED package. Nevertheless this occasional advantage does not compensate for the many disadvantages which are related to parallel drive. The solution requires a single current source per LED. While taking the complete system under consideration the heat sink required for parallel driving is bigger due to the increased power loss in linear current sinks required for this topology.
The benefits of a serial topology outnumber the costs of the LED cooling: a single current source per string, and the parallel switches do not dissipate additional power when the LED is active. There is also intrinsic current matching for all the LEDs and no need for selecting LEDs with matching forward voltage. This topology allows using higher voltages and less conversion losses. Serial drive gives a higher modularity being compatible with pixel light solutions as well as non-pixel light.

Figure 3: NCV78763: Power Ballast and Dual LED Driver for Automotive Front Lighting 2nd gen / 1.6A

Use the comment section below to share your opinion!

What do you think about parallel drive vs. serial drive? Which solution do you see pushing through in the market?