On this page we will take an in-depth look at the primary stage of Mushkin Volta 600 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one GBU1006 rectifying bridge, which supports up to 10 A at 100º C. At 115 V this unit would be able to pull up to 1,150 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 920 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.

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Figure 9: Rectifying bridge.

Two SPA20N60C3 power MOSFET transistors are used on the active PFC circuit, each one capable of delivering up to 20.7 A at 25º C or up to 13.1 A at 100º C in continuous mode, or up to 62.1 A at 25º C in pulse mode, presenting an RDS(on) of 190 mΩ (resistance when the transistor is turned on; the lower this number the better, meaning higher efficiency).

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Figure 10: Active PFC transistors and diode.

The output from the active PFC circuit is filtered by a Japanese electrolytic capacitor from Chemi-Con, labeled at 85º C.

In the switching section, another two SPA20N60C3 power MOSFET transistors are used on the traditional two-transistor forward configuration. The specs for these transistors were already published above.

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Figure 11: Switching transistors.

The primary is controlled by a CM6805 PFC/PWM combo controller.

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Figure 12: PFC/PWM combo controller.

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