PC Power & Cooling Silencer Mk III 750 W Power Supply Review
Primary Analysis
Contents
On this page, we will take an in-depth look at the primary stage of the PC Power &
amp; Cooling Silencer Mk III 750 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 an individual heatsink. 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 10: Rectifying bridge
The active PFC circuit uses two IPP50R199CP MOSFETs, each one supporting up to 17 A at 25° C or 11 A at 100° C in continuous mode (note the difference temperature makes), or 40 A at 25° C in pulse mode. These transistors present a 199 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 controlled by an NCP1653 integrated circuit.
Figure 11: Active PFC controller
The output of the active PFC circuit is filtered by one 560 μF x 400 V Japanese electrolytic capacitor, from Chemi-Con, labeled at 105° C.
Figure 12: Capacitor
In the switching section, another two IPP50R199CP MOSFETs are employed using a resonant configuration. The specifications for these transistors were already discussed above.
Figure 13: The switching transistors, the active PFC diode, and the active PFC transistors
The switching transistors are controlled by an SF29601 resonant controller, which is a proprietary integrated circuit from Super Flower.
Figure 14: Resonant controller
Let’s now take a look at the secondary of this power supply.
