be quiet! Dark Power Pro 10 850 W Power Supply Review

Primary Analysis

On this page we will take an in-depth look at the primary stage of the be quiet! Dark Power Pro 10 850 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses two GBJ2506 rectifying bridges connected in parallel and attached to an individual heatsink. This bridge supports up to 25 A at 100° C. So, in theory, you would be able to pull up to 5,750 W from a 115 V power grid. Assuming 80% efficiency, the bridges would allow this unit to deliver up to 4,600 W without burning themselves out (or 5,175 W at 90% efficiency). Of course, we are only talking about these particular components. The real limit will depend on all the components combined in this power supply.

Figure 11: Rectifying bridges

The active PFC circuit uses two IPW60R125P MOSFETs, each supporting up to 25 A at 25° C or 16 A at 100° C in continuous mode (see the difference temperature makes) or 82 A at 25° C in pulse mode. These transistors present a maximum 125 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.

Figure 12: Active PFC diode and active PFC transistors

The active PFC circuit is controlled by an NCP1654 integrated circuit.

Figure 13: Active PFC controller

The output of the active PFC circuit is filtered by two 390 µF x 420 V Japanese electrolytic capacitors, from Chemi-Con, labeled at 105° C and connected in parallel. This is the equivalent of a single 580 µF x 450 V capacitor.

In the switching section, four IPP60R199CP MOSFETs are employed using a resonant configuration. Each transistor supports up to 16 A at 25° C or 10 A at 100° C in continuous mode or up to 51 A at 25° in pulse mode, with a maximum RDS(on) of 199 mΩ.

Figure 14: The switching transistors

The switching transistors are controlled by a CM6901 integrated circuit.

Figure 15: Resonant controller

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