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Primary Analysis

On this page, we will take an in-depth look at the primary stage of the Fractal Design Newton R3 800 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses two US15KB80R rectifying bridges, which are attached to the same heatsink as the primary semiconductors. Each bridge supports up to 15 A at 101º C. So in theory, you would be able to pull up to 3,450 W from a 115 V power grid. Assuming 80% efficiency, the bridges would allow this unit to deliver up to 2,760 W without burning themselves out (or 3,105 W with 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.

Fractal Design Newton R3 800wFigure 11: Rectifying bridges

The active PFC circuit uses one IPW60R099C6 MOSFET, which supports up to 37.9 A at 25º C or 24 A at 100º C in continuous mode (note the difference temperature makes), or 112 A at 25º C in pulse mode. This transistor presents a 99 mΩ maximum 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.

The active PFC circuit is controlled by an ICE2PCS01 integrated circuit.

Fractal Design Newton R3 800wFigure 12: Active PFC controller

The output of the active PFC circuit is filtered by two 220 µF x 400 V Japanese electrolytic capacitors, from Chemi-Con, labeled at 105º C. These capacitors are connected in parallel, and thus are equivalent to a single 440 µF x 400 V capacitor.

Fractal Design Newton R3 800wFigure 13: Capacitors

In the switching section, this power supply uses two SPW32N50C3 MOSFETs in a resonant configuration. Each transistor supports up to 32 A at 25º C or 20 A at 100º C in continuous mode, or up to 96 A at 25º C in pulse mode, with a maximum RDS(on) of 110 mΩ.

Fractal Design Newton R3 800wFigure 14: Switching transistors, active PFC diode, and active PFC transistor

The switching transistors are managed by a CM6901 resonant controller.

Fractal Design Newton R3 800wFigure 15: Resonant controller

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

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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.