Operating temperature range of switching power supplies from MEAN WELL

One of the most important factors that directly affect the quality of the power system, its reliability and the life of the power supply itself are the temperature conditions of the environment at its location. A feature of switching power supplies is a fairly strong independent heating of structural elements and components in their composition due to the principle of operation and topology, regardless of the power of the supplied load. In other words, the heating of the power supply occurs both at full load, and with its partial presence or even with its complete absence. Therefore, it is important to ensure acceptable operating conditions over the temperature range. MEAN WELL always indicates the permissible temperature range in the Specification for a series of power supplies (for example , power supplies of the PWM series ):

Permissible operating temperature and storage conditions

The most important parameter is not the lower limit of the ambient temperature (this limit actually determines the possibility of starting the power supply at such a temperature), but its upper value - since the power supply's own heating is quite high, it is important to ensure the lowest possible ambient temperature in the place placement of the power supply, for example, due to a sufficient amount of free space around the power supply, or natural or forced air convection around it. The lower the ambient temperature, the lower the temperature of the power supply itself and, accordingly, its operation will occur in the most optimal mode. A number of power supply series have separate components designed to operate in a higher temperature range (for example, electrolytic capacitors for input / output filters at 105°C), but these measures are more likely to increase the reliability of the power supply than to extend its life in difficult conditions.

The dependence of the load on the ambient temperature is linear - in most of the temperature range, the power supply can provide power at full load (100% of the maximum power), when the ambient temperature is heated to +50°C and above to the maximum allowable temperature, the load should be reduced to 50-60%. Depending on the model of the power supply, these parameters may vary, but the general order of values (temperatures and percentage of load) is approximately the same. On the example of power supplies of the ELG-150 series for LED applications :

Graphs of load dependence on ambient and case temperature

For case temperatures over virtually the entire allowable temperature range, from minimum to maximum values, the power supply remains operational and can provide power at full load. In order to understand the conditions of placement and operation of the power supply, MEAN WELL indicates the location for measuring the maximum temperature of the case for a number of applications. According to the specification for power supplies of the XLG-100 series :

Measuring point for maximum housing temperature, using the example of XLG-100

Therefore, when creating a power system, it is advisable to conduct test tests of the functioning of the power supply, including temperature control both at the location of the power supply (its environment), and directly the temperature of the power supply housing. For questions related to the selection and use of MEAN WELL products, please contact Meanwell@chipdip.ru .