Corsair HX850 Gold Power Supply Review

Primary Analysis

On this page we will take an in-depth look at the primary stage of the Corsair HX850 Gold. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses two GBU1006 rectifying bridges connected in parallel and attached to an individual heatsink. Each bridge supports up to 10 A at 100° C. So, in theory, you would be able to pull up to 2,300 W from a 115 V power grid. Assuming 80% efficiency, these bridges would allow this unit to deliver up to 1,840 W without burning themselves out (up to 3,105 W at 90% efficiency). Of course, we are only talking about these particular components. The real limit will depend on all the components combined in this power supply.

Figure 11: Rectifying bridges

The active PFC circuit uses two IPW60R099C6 MOSFETs, each supporting up to 37.9 A at 25° C or 24 A at 100° C in continuous mode (see the difference temperature makes) or 112 A at 25° C in pulse mode. These transistors present a maximum 99 mΩ 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.

Figure 12: Active PFC transistors

The output of the active PFC circuit is filtered by two 390 µF x 420 V Japanese electrolytic capacitors, from Chemi-Con, labeled at 105° C. These capacitors are connected in parallel and are the equivalent of a single 780 µF x 420 V capacitor.

Figure 13: Capacitors

In the switching section, another two IPW60R099C6 MOSFETs are employed using the traditional two-transistor forward configuration. The specifications for these transistors were already discussed above.

Figure 14: Switching transistors

The switching transistors are managed by a CM6802 active PFC/PWM combo controller.

Figure 15: Active PFC/PWM controller

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