Nexus RX-6300 630 W Power Supply Review

Primary Analysis

On this page we will take an in-depth look at the primary stage of Nexus RX-6300. 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 100° C, if a heatsink is used, which is the case (without a heatsink the current limit drops to 3.2 A). So in theory you would be able to pull up to 1,150 W from a 115 V power grid; assuming 80% efficiency, this bridge would allow this unit to deliver up to 920 W without burning. Of course we are only talking about this component and the real limit will depend on all other components from the power supply.

Figure 9: Rectifying bridge.

The active PFC circuit uses two IXTQ26N50P power MOSFET transistors, each one capable of delivering up to 26 A at 25° C in continuous mode (unfortunately the manufacturer does not publish the maximum current at 100° C) or 78 A in pulse mode at 25° C. These transistors present a 230 mΩ resistance when turned on, a characteristic called RDS(on). The lower this number the better, meaning that the transistors will waste less power and the power supply will achieve a higher efficiency.

The electrolytic capacitor in charge of f
iltering the output from the active PFC circuit is Taiwanese from Teapo and labeled at 85° C.

In the switching section, two SPW16N50C3 power MOSFET transistors are used on the traditional two-transistor forward configuration. Each transistor supports up to 16 A at 25° C or 10 A at 100° C (note the difference temperature makes) or 48 A in pulse mode at 25° C, presenting an RDS(on) of 280 mΩ.

Figure 10: +5VSB switching transistor, one of the active PFC transistors and switching transistors.

This power supply uses the famous CM6800 active PFC/PWM combo controller soldered on the solder side of the printed circuit board.

Figure 11: Active PFC/PWM combo controller.

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