PC Power & Cooling Silencer Mk II 500 W Power Supply Review

Primary Analysis

On this page we will take an in-depth look at the pr
imary stage of the PC Power & Cooling Silencer Mk II 500 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one GBU805 rectifying bridge on its primary attached to the same heatsink as the active PFC transistors. This component supports up to 8 A at 100° C, so in theory, you would be able to pull up to 920 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 736 W without burning itself out. Of course, we are only talking about this component, and the real limit will depend on all the other components in this power supply.

Figure 10: Rectifying bridge

The active PFC circuit uses two FMV19N60E MOSFETs, each one capable of delivering up to 19 A at 25° C (unfortunately the manufacturer doesn’t say the limit at 100° C) in continuous mode, or up to 76 A in pulse mode at 25° C. These transistors present a 310 mΩ resistance when turned on, a characteristic called RDS(on). The lower this number the better, meaning that the transistors will waste less power and the power supply will have a higher efficiency.

Figure 11: Active PFC transistors

The electrolytic capacitor that filters the output of the active PFC circuit is Japanese, from Chemi-Con, and labeled at 105° C.

In the switching section, another two FMV19N60E MOSFETs power MOSFETs are used in the traditional two-transistor forward configuration.

Figure 12: Switching transistors

The primary is controlled by a FAN4800 active PFC/PWM combo.

Figure 13: Active PFC/PWM combo controller

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