Corsair AX760i Power Supply Review

Secondary Analysis

As one would expect in a high-efficiency power supply, the Corsair AX760i 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 BSC030N04NS G MOSFETs, each one supporting up to 100 A at 25° C or 84 A at 100° C in continuous mode, or up to 400 A at 25° C in pulse mode, with a maximum RDS(on) of 3 mΩ. These transistors are located on a daughterboard together with the main transformer. The +12 V filtering capacitors are also located on this board, and they are all solid.

Figure 19: The +12 V transistors

Figure 20: Solid capacitors used by the +12 V output

As explained, the +5 V and +3.3 V outputs are produced by two DC-DC converters, each one located on a separate printed circuit board. Each converter is controlled by an NCP1587A integrated circuit and uses four BSC050N03LS G MOSFETs, each one supporting up to 80 A at 25° C or 51 A at 100° C in continuous mode and up to 320 A at 25° C in pulse mode, with a maximum RDS(on) of 5 mΩ.

Figure 21: One of the DC-DC converters

Figure 22: One of the DC-DC converters

The outputs of the power supply are monitored by the digital signal processor.

Most capacitors available in the secondary are solid (see Figure 20). The few electrolytic capacitors available are also Japanese, from Chemi-Con and Rubycon, and labeled at 105° C, as usual. As you can see in Figure 23, several solid capacitors are also used on the printed circuit board of the modular cabling system.

Figure 23: Capacitors