In Win GreenMe 650 W Power Supply Review

Primary Analysis

On this page we will take an in-depth look at the primary stage of the In Win GreenMe 650 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses two GBU605 rectifying bridges, which are attached to the same heatsink as the active PFC and switch transistors. Each bridge supports up to 6 A at 100° C. 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. The 750 W model uses two 8 A bridges here.

Figure 11: Rectifying bridges

The active PFC circuit uses two TK20J50D MOSFETs, each supporting up to 20 A at 25° C in continuous mode or 80 A at 25° C in pulse mode. (Unfortunately, the manufacturer doesn’t state the current limits at 100° C.) These transistors present a maximum 270 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. The 750 W model uses different transistors here.

The output of the active PFC circuit is filtered by one 390 µF x 420 V Japanese electrolytic capacitor, from Matsushita (Panasonic), labeled at 105° C.

Figure 12:  Capacitor

In the switching section, two TK15J50D MOSFETs are employed using the traditional two-transistor forward configuration. Each of these transistors supports up to 15 A at 25° C in continuous mode or up to 60 A at 25° C in pulse mode, with a maximum RDS(on) of 400 mΩ. Unfortunately, the manufacturer doesn’t publish the current limits at 100° C. The 750 W model uses more powerful transistors here.

Figure 14: Active PFC/PWM combo controller

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