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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.

Fractal Design Newton R3 800wFigure 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.

Fractal Design Newton R3 800wFigure 17: One of the DC-DC converters

Fractal Design Newton R3 800wFigure 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.

Fractal Design Newton R3 800wFigure 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.

Fractal Design Newton R3 800wFigure 20: Capacitors

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Gabriel Torres is a Brazilian best-selling ICT expert, with 24 books published. He started his online career in 1996, when he launched Clube do Hardware, which is one of the oldest and largest websites about technology in Brazil. He created Hardware Secrets in 1999 to expand his knowledge outside his home country.