Enermax Liberty ECO 500 W Power Supply Review

Primary Analysis

On this page we will take an in-depth look at the primary stage of Liberty ECO 500 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one GBU10J rectifying bridge in its primary, which support up to 10 A at 100° C. This component is clearly overspec’ed: 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 this component. Of course we are only talking about this component and the real limit will depend on all other components from the power supply.

Figure 10: Rectifying bridge.

For the active PFC circuit Liberty ECO 500 W uses two 2SK2698 power MOSFET transistors, which one capable of delivering up to 15 A in continuous mode  or up to 60 A in pulse mode, both values rated at 25° C.

The active PFC capacitor is Japanese from Hitachi and rated at 85° C.

In the switching section, another two 2SK2698 power MOSFETs are used on the traditional two-transistor forward configuration. The specs for these transistors you can read above.

Figure 11: Two of the four power MOSFET transistors used on the primary.

The primary is controlled by a CM6802 PWM/PFC controller combo, which is a new version of the famous CM6800 that consumes less power.

Figure 12: PWM/PFC controller.

Now let’s analyze the secondary section from Liberty ECO 500 W.