Let’s now take an in-depth look on the primary stage from MSI Turbostream 600 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.
This power supply uses one GBU1006 rectifying bridge on its primary, capable of delivering up to 10 A at 100º C, if it has a heatsink attached, which is the case (without the heatsink the current limit drops to 3.2 A). This is an adequate rating for a 600 W power supply. The reason why is that 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.
On this power supply the rectifying bridge comes protected by a rubber tape, which was removed on Figure 8.
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Figure 8: Rectifying bridge.
The active PFC circuit uses two FQA24N50 power MOSFET transistors, each one capable of delivering up to 15.2 A at 100º C (or 24 A at 25º C, see the difference temperature makes). They are located on the same heatsink as the switching transistors.
The active PFC capacitor is from Teapo (Taiwanese) and rated at 85º C.
As we mentioned before, this power supply uses an active PFC coil that looks like a transformer. If we didn’t have the experience we have we could assume that this unit had passive PFC, but this isn’t the case as the active PFC transistors are present. These two components (capacitor and coil) can be seen on Figure 9, where you can also see the MOV from the transient filtering stage.
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Figure 9: Active PFC capacitor and coil.
The switching section from this power supply uses two SPW20N60C3 power MOSFET transistors in the traditional two-transistor forward configuration. Each switching transistor can handle up to 13.1 A at 100º C (or 20.7 A at 25º C, once again see the difference temperature makes).
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Figure 10: Switching transistor, active PFC transistor and the other switching transistor (the second active PFC transistor is on the other side of the heatsink).
The primary is controlled by a CM6800 integrated circuit, which is a very popular PFC/PWM combo controller.
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Figure 11: PFC/PWM controller.
As briefly mentioned, all components found on both primary and secondary are identical to the ones used on Rosewill RD600N-2DB-SL.
