On this page we will take an in-depth look at the primary stage of Corsair TX950W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses two GBU1506 rectifying bridges connected in parallel. Each bridge supports up to 15 A at 100º C, if a heatsink is used, which is the case. So in theory you would be able to pull up to 3,450 W from the power grid; assuming 80% efficiency, the bridges would allow this unit to deliver up to 2,760 W without burning them. Of course, we are only talking about these components, and the real limit will depend on all the other components in this power supply.

click to enlarge
Figure 9: Rectifying bridges.

The active PFC circuit uses two SPW35N60C3 power MOSFET transistors. Each MOSFET is capable of delivering up to 34.6 A at 25º C or 21.9 A at 100º C in continuous mode (note the difference temperature makes) or 103.8 A in pulse mode at 25º C. These transistors present a 100 mΩ 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.

click to enlarge
Figure 10: Active PFC transistors.

The electrolytic capacitor in charge of filtering the output from the active PFC circuit is Japanese from Chemi-Con and is labeled at 105º C. This is good for two reasons, first, Japanese capacitors do not leak; and second, usually manufacturers use 85º C capacitors here, so it is good to see a manufacturer using a capacitor with a higher temperature rating.

In the switching section, two SPW20N60C3 power MOSFET transistors are used on the traditional two-transistor forward configuration. Each transistor supports up to 20.7 A at 25º C or 13.1 A at 100º C (note the difference temperature makes) or 62.1 A in pulse mode at 25º C, presenting an RDS(on) of 190 mΩ.

click to enlarge
Figure 11: Switching transistors.

This power supply uses the famous CM6800 active PFC/PWM combo controller.

click to enlarge
Figure 12: Active PFC/PWM combo controller.

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