The development of LED heat to PCB

Today, The complexity of LED models, compared to the plate, which can contain hundreds of components, increases the difficulty in maintaining compatibility thermal not only involves placing the components and mechanical design, but also increasing concern. Increasing reliability and thermal design is an integral part of the design process, especially when it comes to high-power IC and LED.

With the escalation of the LED heat, several key elements to be shown what the meaning of the LED industry thermal management. The forward voltage begins to drop. The voltage drop can be caused to a greater strain on the components related to LED drivers increases its temperature.

Resistance in the circuit increase is driven by the current. If the temperature of the LED continues to increase, the optical wavelength can be changed. The wavelength can lead to an increase in orange-red or white LED, the LED lights up blue. These color changes generally increases with AlInGaP technologies (red, orange, orange and yellow). In addition, a light is on and lose their thermal efficiency emphasized the light intensity decreases. If the LED thermal management continue racing out of control, the LED junction rupture caused a state of complete thermal errors.

Thermal fault of the complete loss of function through electronic fusion, partial evaporation of the component, thermal fracture of a carrier or separation between the conductors. Thermal problems can also lead to common limitations and hot spots on the map.

Thermal management techniques focus on efficiency, the heat from high-power Designs creates and provides a high thermal conductivity, and in maintaining a low coefficient of thermal expansion (CTE), while the administration shifts CTE between the LED components, connections and PCBs.

LED manufacturer and integrated circuits using a variety of packaging chips and components often have a lower CTE than the standard PCB. The resulting thermal imbalance between the device and PCB. The environment in which the board is that its performance can also affect performance. For each increase of 20 ° C, the temperature of the component, the failure rate is doubled.

All products of this type using VDC (UL 94-V0) material to remove from the fusion of the board during the reflow and / or wave soldering process, some of these concerns, to protect the engineer.

While the LED chip manufacturers do their part to do this thermal management devices improve, the designer must take into account the heat dissipation, so that the use of materials for the container (such as UL (94 – V0)) pay particular attention to the mounting holes . Separators and use different connection techniques is essential in obtaining adequate air circulation to help heat dissipation. Discover our selection.

The new patents are granted, that the industry developed a number of new materials for thermal management and LED-technology practice. There are several important events that have in the toolbox of PCB designers and experienced engineers.

Proven techniques exist, such as theft of copper, an increase in line width, and with the holes for heat dissipation. New techniques and developments include the use of thermal modeling software, the material of the new heat sink with high conductivity carbon-composite layers board, special roofing materials, and the plates from the edge. Now I want the latest developments in the area of heat sink, which have historically served as a workhorse for the thermal management of PCB design.

The development of the heat sink

Keep sinks to the LED components at temperatures below their operating temperature. There are many different styles and different ways to optimize the heat sink.

Over time, technology has progressed to the use of new materials such as carbon and boron nitride. These materials are applied in several layers in order to efficiently transport PCB heat from one layer to another fiber. Due to the high cost, however, these materials, limited use in the future are printed circuit boards and not replace the aluminum heat sink in many LED applications.

Application to aluminum or copper-based heatsink to keep increasing acceptance in many LED applications due to their low cost and ideal characteristics of heat dissipation. Aluminum has a very acceptable thermal conductivity, while copper is approximately twice as high. Aluminum heat sinks are low cost, cost more than copper and weigh more. Consequently, aluminum for the most profitable applications will be chosen, and copper is used in some places where the queen on the cost side performance.

Finally, while, most of the cooling fins to increase an easy way to the surface for heat radiation and heat conduction. The newly developed special material aluminum fins driver is reported that 15 percent of the material in the previous fin radiators are used. These recent developments are to be sure, such as the heat sink device itself indispensable.