A 45W AC/DC enclosed type switching power supply with universal AC input and active PFC function. These limited power sources comply with UL1310 Class II that under any situation the output power will be less than 100VA to 5A. The high IP64 level design can protect the electronic components from dust and moisture damage and making it useable for indoor and outdoor applications. Thanks to the simplified single stage PFC topology the required high power factor for the lighting industry can be achieved economically. Efficiencies are as high as 87.5% and hence can operate between -30°C and +50°C using only free air convection.