Corsair TX750M Power Supply Review

Primary Analysis

On this page we will take an in-depth look at the primary stage of the Corsair TX750M. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses two GBU606 rectifying
bridges, attached to an individual heatsink. These bridges support up to 6 A at 100° C each, so in theory, you would be able to pull up to 1,380 W from a 115 V power grid. Assuming 80% efficiency, the bridges would allow this unit to deliver up to 1,104 W without burning themselves out. 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 10: Rectifying bridges

The active PFC circuit uses two SPW20N60C3 MOSFETs, each supporting up to 20.7 A at 25° C or 13.1 A at 100° C in continuous mode (note the difference temperature makes), or 62.1 A at 25° C in pulse mode. These transistors present a 190 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 11: Active PFC transistors

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

In the switching section, two SiHG20N50C MOSFETs are used in the traditional two-transistor forward configuration. Each transistor supports up to 20 A at 25° C or 11 A at 100° C in continuous mode or up to 80 A at 25° C in pulse mode, with an RDS(on) of 270 mΩ.

Figure 12: Switching transistors

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

Figure 13: Active PFC/PWM combo controller

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