Corsair GS800 Power Supply Review

Primary Analysis

On this page we will take an in-depth look at the primary stage of the Corsair GS800 For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply use one GBU1506 rectifying bridge, which is attached to the same heatsink where the active PFC transistors are located. This bridge supports up to 15 A at 55° C so, in theory, you would be able to pull up to 1,725 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 1,380 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 TK20J60U MOSFETs, each one capable of delivering up to 20 A at 25° C in continuous mode (unfortunately the manufacturer doesn’t publish the current limit at 100° C), or up to 40 A in pulse mode at 25° C. These transistors present a 165 m&Om
ega; 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 achieve a higher efficiency.

Figure 11: Active PFC transistors

The output of the active PFC circuit is filtered by a capacitor from Samxon, labeled at 105° C.

In the switching section, two SPA16N50C3 MOSFETs are used, installed in the two-transistor forward configuration. These transistors support up to 16 A at 25° C or up to 10 A at 100° C in continuous mode, or up to 48 A at 25° C in pulse mode, with an RDS(on) of 280 mΩ.

Figure 12: Switching transistors

The primary is controlled by the famous CM6800 active PFC/PWM combo controller.

Figure 13: Active PFC/PWM combo controller

Now let’s take a look at the secondary of this power supply.