Are traditional industrial-grade power supplies suited for LED applications?
A: There are three main reasons why industrial-grade power supplies (such as the Xgen modular power supply) are unsuitable for many LED applications.
Firstly, LEDs are current driven devices whose brightness is proportional to their forward current. In order to attain a constant, predictable light output, a driver which is designed to output a constant current over a wide load range is required (i.e. the voltage will vary in order to maintain a constant current). Traditional power supplies are constant voltage supplies, which output a constant voltage over a wide load (the current output will depend upon the load). Constant voltage supplies require additional circuitry in order to drive LEDs reliably.
Secondly, many supplies are designed to operate up to a certain maximum temperature, at which point their power rating is decreased (derating) in order to ensure a safe operating environment for the supplies internal components. LED drivers are often required to operate at much higher ambient temperatures (sometimes greater than 60°C) without any temperature derating. Many LED drivers utilise potting or encapsulant which aids in heat transmission away from vital components to facilitate this high temperature operation.
Finally, traditional power supplies do not have waterproof and lightning protection features for outdoor operation. The potting used in many LED drivers facilitates the waterproof requirements, while LED drivers designed for outdoor use will be designed with surge protection for lightening requirements.