be quiet! Dark Power Pro 10 650 W Power Supply Review

Secondary Analysis

The be quiet! Dark Power Pro 10 650 W uses a DC-DC design in its secondary. This means that the power supply is basically a +12 V unit, with the +5 V and +3.3 V outputs produced by two smaller power supplies connected to the main +12 V rail. Also, the +12 V output uses a synchronous design, where the rectifiers were replaced with MOSFETs. Both designs are used to increase efficiency.

The maximum theoretical current that each line can deliver is given by the formula I / (1 – D) where D is the duty cycle used and I is the maximum current supported by the rectifying diode. As an exercise, we can assume a duty cycle of 30 percent.

The +12 V output uses four IRFB3206GPbF MOSFETs, each supporting up to 120 A at 25° C in continuous mode or 840 A at 25° C in pulse mode, with a maximum RDS(on) of 3 mΩ.

Figure 17: The +12 V MOSFETs

As explained, the +5 V and +3.3 V outputs are produced by two DC-DC converters
. Both are located on the same daughterboard that is soldered to the main printed circuit board. The two converters are controlled by a single integrated circuit, an APW7158. Each converter uses four IRLR8729pbF MOSFETs, each one supporting up to 58 A at 25° C or 41 A at 100° C in continuous mode or up to 260 A at 25° C in pulse mode, with a maximum RDS(on) of 8.9 mΩ.

Figure 18: The DC-DC converters

Figure 19: The DC-DC converters

This power supply uses a PS232F monitoring integrated circuit, which supports over voltage (OVP), under voltage (UVP), and over current (OCP) protections. There are four +12 V over current protection (OCP) channels, matching the number of +12 V rails advertised by the manufacturer.

Figure 20: Monitoring circuit

The electrolytic capacitors that filter the outputs are also Japanese, from Chemi-Con and Rubycon, and labeled at 105° C, as usual. This unit also makes use of solid capacitors.