Corsair AX760 Power Supply Review

Primary Analysis

On this page, we will take an in-depth look at the primary stage of the Corsair AX760. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial. &nbsp
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This power supply uses two GBJ1506 rectifying bridges, which are attached to an individual heatsink. Each bridge supports up to 15 A at 100° C. In theory, you would be able to pull up to 3,450 W from a 115 V power grid. Assuming 80% efficiency, the bridges would allow this unit to deliver up to 2,760 W without burning themselves out (or 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. The AX760i version uses a single 25 A bridge here.

Figure 11: Rectifying bridges

The active PFC circuit uses two IPP60R199CP MOSFETs, each one supporting up to 16 A at 25° C or 10 A at 100° C in continuous mode (note the difference temperature makes), or 51 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. These are the same components used on the AX760i.

Figure 12: The active PFC diode and transistors

The active PFC circuit is controlled by an NCP1654 integrated circuit. On the AX760i, the active PFC circuit is controlled by the digital signal processor. 

Figure 13: Active PFC controller

The output of the active PFC circuit is filtered by two 330 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 660 μF x 420 V capacitor. The AX760i uses a single 560 µF x 420 V capacitor here.

Figure 14: Capacitors

In the switching section, four IPP50R250CP MOSFETs are employed using a full-bridge, resonant configuration. Each transistor supports up to 13 A at 25° C or 9 A at 100° C in continuous mode or up to 31 A at 25° C in pulse mode, with a maximum RDS(on) of 250 mΩ. The AX760i uses a different configuration, with only two stronger transistors.

Figure 15: The switching transistors

The switching transistors are controlled by a CM6901 resonant controller, which is physically located on the same printed circuit board as the +12 V transistors. On the AX760i, the switching transistors are controller by the digital signal processor.

Figure 16: Resonant controller

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