Arctic Cooling Fusion 550RF Power Supply Review

Secondary Analysis

Arctic Cooling Fusion 550RF uses four Schottky rectifiers on its secondary.

The maximum theoretical current 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. Just as an exercise, we can assume a typical duty cycle of 30%. Of course the maximum current (and thus power) this line can really deliver will depend on other components, especially the coil.

+12 V rectification is done by two SBR30A50CT Schottky rectifiers, each one supporting up to 30 A (15 A per internal diode at 110° C), so we have a maximum theoretical current of 43 A (15 A x 2 / 0.70), which corresponds to 514 W.

The +5 V output is produced by one STPS30L30CT Schottky rectifier, which supports up to 30 A (15 A per internal diode) at 140° C. This translates into a maximum theoretical current of 21 A or 107 W.

Another STPS30L30CT is used to rectify the +3.3 V output, giving a maximum theoretical current of 21 A or 71 W for this output.

Figure 12: +3.3V, +5V and +12 V rectifiers.

The secondary is monitored by an HY510N integrated circuit, which is installed on a small daughterboard and provides some of the power supply protections, like under voltage (UVP) and over voltage (OVP).

Figure 13: Monitoring circuit.

This unit uses a tiny semiconductor thermal sensor, which is located on the solder side from the printed circuit board.

The electrolytic capacitors from the secondary are from OST, labeled at 105° C as usual.

All components from the secondary are identical to the ones used on Corsair VX450W and Antec EarthWatts 500 W, so we can clearly say that the reviewed power supply and these other two units are identical.