Rosewill SilentNight 500 W Power Supply Review

Primary Analysis

On this page, we will take an in-depth look at the primary stage of the Rosewill SilentNight 500 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.         

This power supply uses one US30K80R rectifying bridge, which is attached to the same heatsink where the active PFC and switching transistors are located. This bridge supports up to 30 A at 97° C. In theory, you would be able to pull up to 3,450 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 2,760 W without burning itself out (or 3,105 W at 90% efficiency). Of course, we are only talking about this particular component. The real limit will depend on all the components combined in this power supply.

Figure 9: Rectifying bridge

The
active PFC circuit uses one IPW50R140CP MOSFET, which supports up to 23 A at 25° C or 15 A at 100° C in continuous mode (note the difference temperature makes), or 56 A at 25° C in pulse mode. These transistors present a 140 mΩ maximum resistance when turned on, a characteristic called RDS(on). The lower the number the better, meaning that the transistor will waste less power, and the power supply will have a higher efficiency.  

The active PFC circuit is managed by an NCP1653A active PFC controller.

Figure 10: Active PFC controller

The output of the active PFC circuit is filtered by one 470 µF x 400 V Japanese electrolytic capacitor, from Chemi-Con, labeled at 105° C.

Figure 11: Capacitor

In the switching section, two IPP50R199CP MOSFETs are employed using a resonant configuration. Each transistor supports up to 17 A at 25° C or 11 A at 100° C in continuous mode or up to 40 A at 25° C in pulse mode, with a maximum RDS(on) of 199 mΩ. 

Figure 12: The two switching transistors, the active PFC diode, and the active PFC transistor

The switching transistors are controlled by Super Flower’s proprietary SF29601 controller.   

Figure 13: Resonant controller

Let’s now take a look at the secondary of this power supply.