A Look Inside
Fractal Design's Integra R2 750W is based on a HEC OEM
design.
On the primary side you find a rectifier. We can find a PCB housing the FAN4800.
The FAN4800 controls the PFC Booster and the Push-Pull converter. This PSU has a
Push-Pull topology using two Mosfets and two Diodes according to the following
primary sided principle:
link
This is an old school standard topology; simple and proven, but it will not
achieve any new efficiency records. Because this topology requires hard
switching from the Mosfets (Switching Mosfets under voltage and current
generates losses) this topology is more and more replaced in the PC PSU market
by resonant topologies. The transformer has on the secondary side two coils one
for 12V and one for 5V. 3.3V is generated from the 5V Coil. This is the classic
old PSU topology.
The APFC Capacitor with 470uF at 400V and 85°C from Teapo. The PFC Booster uses
a BCY10-600 Hyperfast recovery diode and 3 60R190C6 Mosfets. This is ok for a
PSU in this price range; SiC Diodes are still quite expensive. For rectifying
the secondary side Schottky diodes are used. The Output filter Capacitors are
from Teapo. 105°C is written on them.
The OCP, UVP, OVP is done by a WT7527.