Fractal Design Tesla R2 650 W Power Supply Review

Secondary Analysis

As one would expect in a high-efficiency power supply, the Fractal Design Tesla R2 650 W uses a synchronous design, where the Schottky rectifiers are replaced with MOSFETs. Also, the reviewed product 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. Both designs are used to increase efficiency.

The +12 V output uses four IPP041N04N MOSFETs, each one supporting up to 80 A at 100° C in continuous mode, or up to 400 A at 25° C in pulse mode, with a maximum RDS(on) of 4.1 mΩ. The Rosewill FORTRESS-650 uses four IPP023N04N G, which provide higher current limits and a lower RDS(on).

Figure 16: The +12 V transistors

As explained, the +5 V and +3.3 V outputs are produced by two DC-DC converters, located on a daughterboard soldered to the main printed circuit board. Each converter is controlled by a CAT7523 integrated circuit and uses a pair of IPD031N03L MOSFETs, each supporting up to 90 A at 100° C in continuous mode and up to 400 A at 25° C in pulse mode, with a maximum RDS(on) of 3.1 mΩ.

Figure 17: The DC-DC converters

Figure 18: The DC-DC converters

The outputs of the power supply are monitored by a GR8313 integrated circuit, which only supports over voltage (OVP) and under voltage (UVP) protections. 

Figure 19: Monitoring circuit

This power supply uses a mix of solid and electrolytic capacitors in its secondary. The electrolytic capacitors are from Teapo and labeled at 105° C, as usual. The solid capacitors are from CapXon. The Rosewill FORTRESS-650 uses Japanese capacitors here.

Figure 20: Capacitors