On this page we will take an in-depth look at the primary stage of Thermaltake Toughpower XT 750 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one GBJ1506 rectifying bridge in its primary (the same one used on Toughpower 750 W), supporting up to 15 A at 100º C, so in theory, you would be able to pull up to 1,725 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 1,380 W without burning itself. Of course we are only talking about this component and the real limit will depend on all other components from the power supply.

Two SPW20N60C3 power MOSFETs are used on the active PFC circuit, each one capable of delivering up to 20.7 A at 25º C or 13.1 A at 100º C in continuous mode (note the difference temperature makes) or up to 62.1 A at 25º C in pulse mode. These transistors present a maximum resistance of 190 mΩ when turned on, a characteristic called RDS(on). This number indicates the amount of power that is wasted, so the lower this number the better, as less power will be wasted thus increasing efficiency. These are the same transistors used on Toughpower 750 W.

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Figure 11: Rectifying bridge and active PFC transistors.

The electrolytic capacitor in charge of filtering the output from the active PFC circuit is Japanese from Hitachi and rated at 85º C. This is exactly the same capacitor used on Toughpower 750 W.

In the switching section, another two SPW20N60C3 power MOSFET transistors are used. These are the same transistors used on Toughpower 750 W.

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Figure 12: Switching transistors.

This power supply uses a CM6802 active PFC/PWM combo controller. Here is the main difference between the primary from Toughpower 750 W and from the new Toughpower XT 750 W. The previous model used a CM6800 controller. The difference between the two is the efficiency goal: CM6800 targets 80% efficiency, while CM6802 targets 82% efficiency.

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Figure 13: Active PFC/PWM combo controller.

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