Fractal Design Newton R3 800 W Power Supply Review

Secondary Analysis

As one would expect in a high-efficiency power supply, the Fractal Design Newton R3 800 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 six IPP023N04N MOSFETs, each one supporting up to 90 A at 100º C in continuous mode, or up to 400 A at 25º C in pulse mode, with a maximum RDS(on) of only 2.3 mΩ.

Figure 16: The +12 V transistors

As explained, the +5 V and +3.3 V outputs are produced by two DC-DC converters. Each converter is located on a small daughterboard present in the secondary of the power supply, each one controlled by a CAT7523 integrated circuit and using two IPD031N03L G MOSFETs, each one supporting up to 90 A at 100º C in continuous mode, or up to 400 A at 25º C in pulse mode, with a maximum RDS(on) of only 3.1 mΩ.

Figure 17: One of the DC-DC converters

Figure 18: One of the DC-DC converters

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

Figure 19: Monitoring circuit

The electrolytic capacitors from the secondary are from Chemi-Con and Teapo, and labeled at 105º C, as usual. A few solid capacitors are also used.

Figure 20: Capacitors