Corsair AX760i Digital Power Supply Review

A look inside the AX760i

It would appear that Yate Loon
D14BH-12 fans are Corsair’s favorite, as they can be found in most of their
power supplies. The AX760i is no exception. The ball bearing fan has a maximum
speed of 2800RPM, which is unlikely to ever reach since, as you will read in
the following pages, the thermal control circuit will not even turn on the fan
while the unit is lightly loaded. A
simple ambient temperature probe has been placed next to the fan’s engine,
monitoring the intake (ambient) air temperature.

It appears that the AX760i is a mini
AX1200i not only externally but internally as well. Corsair seems to have
ditched the Seasonic design they have been using for the AX750 and went with a
Flextronics design for their new AX760i units. We are not currently aware if
the plain AX760 is based on a Flextronics design as well or if Corsair is still
using a Seasonic design for that. Apparently, the AX1200i must have been a
great success for Corsair to approach Flextronics again for their smaller
units. Flextronics did not let Corsair down either, as the AX760i is every bit
as well made as the larger AX1200i, without any structural flaws and with
excellent soldering points.

The AX760i is narrower than the
AX1200i and so Corsair had to ditch the A/C receptacle EMI filter, as that
would block the installation of other components. Nevertheless, the filtering
stage of the AX760i is excellent, with six Y capacitors, two X type capacitors,
two chokes and a MOV.

We found the bridge rectifier mounted
on its own, fairly large dedicated heatsink. The heatsink is not large because
the transistor is inefficient but because Corsair has this unit operating
without any active cooling at low loads. Next to the bridge rectifier, the APFC
circuit starts with a massive filtering coil and a 420V/560uF 105C capacitor
from Panasonic, with the diode and transistors on their own dedicated heatsink.
The transistors forming the primary side of the LLC resonant converter have
been placed on another heatsink, all the way to the other side of the main
board.

The secondary side rectifier (LLC
type) has been placed on a vertical board, ending to a thick metallic bar which
distributes the 12V line around to the other PCBs and sensing circuits, while
it also serves as a basic heatsink. The 5V DC to DC conversion circuit can be
seen on a vertical PCB to the left side of the rectifier and the 3.3V DC to DC
conversion circuit on a separate vertical PCB to the right side of the
rectifier. The secondary capacitors are a mix of Rubycon and Nippon Chemi-Con
products. Most of the power distribution takes place directly on the PCB
holding the modular connectors, which thick metallic rails transferring the
large lines about the plugs.