[VIDEO] ERP Power: Effect of Local Ambient Air Temperature on Case Temperature of LED Driver

By Roger ElliottApril 20, 2017

Today, thermal analysis is a pivotal factor in nearly all modern electronic system designs. The analysis is crucial for system designers to ensure that components don’t overheat in a way that affects the overall functionality of a system.

Overheating of a component or the entire system is a primary concern for LED designs and it’s important for system engineers to carefully determine the local ambient air temperature of their component of interest and the area encompassing it. In this article, we will discuss the effect of local ambient air temperature (Ta) on the case temperature (Tc) of the driver.

In Part 2 of ERP Power's "Ask the Expert" video series, FAE Director for the Americas Vachik Javadian discusses Ambient Air Temperature and case temperature of the LED Driver. Learn more about common issues faced by LED designers after watching the video! 

There are obviously several reasons that can change the case temperature of the driver, but the most common reason is driver placement. Typically, drivers are mounted right on top of the LEDs, which, if possible, should be completely avoided.

Since the LEDs are the main source of heat generation, and it is the nature of heat to go upwards, it’s likely the driver will be exposed to the maximum amount of heat if it is placed on top of the LEDs. This leads to a surge in the local ambient air temperature, and subsequently, a rise in the case temperature.

Although the outer ambient temperature might have some connection with the case temperature, LED designers should keep in mind that it is the local ambient air temperature inside the chamber that has a one to one relationship with the Tc of the driver.

It is very important to keep the temperature inside the chamber as low as possible because that is what, precisely, matters to the driver. Various case studies suggest that a surge in the local ambient air temperature inside the chamber is directly proportionate to the rise in Tc. For instance, if the local ambient air temperature is raised by 40 C, it will get translated into the Tc and cause the case temperature to rise by exactly 40 C. This is extremely crucial because an upsurge in the Tc can dramatically reduce the driver life.

So, in order to keep the Tc down, LED designers should do a thorough thermal analysis to make sure the local ambient air temperature is kept as cool as possible. A great way to ensure that is to keep enough holes and air ventilation to allow the heat to dissipate, which will lower down both the Ta and the Tc.

Local ambient air temperature is a key factor in LED driver design because its rise can adversely affect the Tc of a system. Though it’s not possible in every design, it is advisable not to mount the driver right on top of the LEDs because that’s where the maximum heat is generated.  Taking this into account when mounting your LED driver will help increase the life cycle of your product.