Cooler Master Extreme 2 475 W Power Supply Review

Primary Analysis

On this page we will take an in-depth look at the primary stage of the Cooler Master Extreme 2 475 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses one GBU806 rectifying bridge, which is attached to the same heatsink as the switch transistors. This bridge 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 particular component. The real limit will depend
on all the components combined in this power supply.

Figure 10: Rectifying bridge

As mentioned, this unit doesn’t have an active PFC circuit. The voltage doubler circuit uses two 560 µF x 200 V electrolytic capacitors from Teapo, labeled at 105° C.

The Cooler Master Extreme 2 475 W uses a single-transistor forward configuration in its switching section. Two 2SK4115 MOSFETs are connected in parallel to double the maximum current the switching section supports. Each of these transistors supports up to 7 A at 25° C in continuous mode or up to 21 A at 25° C in pulse mode, with a maximum RDS(on) of 1.6 Ω, which is extremely high. Unfortunately, the manufacturer doesn’t publish the current limits at 100° C.

Figure 11: One of the switching transistors

The primary is managed by a TL3843 PWM controller.

Figure 12: PWM controller

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