A Look Inside

Before reading this page we strongly suggest a look at this article, which will help you understand the internal components of a PSU better.


The unit's under populated PCB is small and the same applies to its heatsinks; somewhat expected since thermal dissipation is highly reduced due to its high efficiency. On the primary side, we meet an Active Clamp Reset Forward (ACRF) topology that offers high efficiency and good power handling capability. Up to a certain power level, the Active Clamp Reset Forward (ACRF) topology cannot effectively compete with other topologies like the Double Forward or Full Phase Shift topology. In ACRF, two mosfets are used with one playing the role of the main switcher (Q1), while the other is the reset switch (Q2) that disconnects the main capacitor while Q1 is active. Power is also only transferred from the primary to the secondary side while Q2 is open. The main advantage of ACRF is the almost lossless switching of Q1 since the drain voltage is very low while it is turned off. This means higher efficiency. Finally, on the secondary side, synchronous rectification is used, offering lower energy losses compared to passive rectification.


The transient filtering starts at the AC receptacle and we find two Y caps there. It continues on the main PCB with two X and two Y caps, two CM chokes, and an MOV. The latter is a pleasant surprise since FSP didn't use MOVs in the previous AURUM line, claiming that the MIA IC offers over voltage protection that allow it to absorb excess surges coming from the power grid.


To increase efficiency, FSP utilized PI's (Power Integrations) CAP004DG discharge IC, which blocks current through X cap discharge resistors when AC voltage is connected, and automatically discharges X caps through the aforementioned resistors when AC is disconnected. X caps tend to keep their charge for quite a long time once AC power is cut off; bleeding resistors are used here for safety. However, an amount of energy is lost on these resistors when the PSU is operating, something that the CAP004DG takes care of by isolating the bleeding resistors from the circuit.


The single bridge rectifier is bolted on a dedicated heatsink and its model number is GBU 15L06. It can rectify up to 15 A of current, easily able to handle the capacity of this unit.


In the APFC, we meet two Infineon IPA60R125CP fets, and the necessary boost diode bolted to a dedicated small heatsink. The hold-up cap is provided by Nippon Chemi-Con (390μF, 450V, 105°C, KMR series). As we already mentioned at the start of this page, this PSU uses an ACRF topology in which the role of the reset switch is played by an FQPF3N80C fet, while the main switcher is a SPA17N80C3 fet. The PFC/PWM controller is the FSP 6600 IC for which we didn't find any documentation on the net.


On the secondary side, synchronous design is used. The rectification of the +12V rails is handled by two mosfets that we couldn't identify because the main transformer totally blocked the view (we didn't feel like de-soldering this heatsink). The minor rails are generated through DC-DC converters and their mosfets are installed on the solder side of the main PCB. In total, four IPD031N03L fets are used. The PWM controller for both VRMs is the proprietary FSP 6601 IC. All filtering caps on the secondary side are provided by Chemi-Con (105°C, KZE series).


Housekeeping duties are handled by a Weltrend WT7579 supervisor IC for which we didn't find any documentation online.


Some heatshrinks around these naked wires would be nice!


We didn't find any extra filtering caps on the modular PCB. We also can't help but wonder why it was left unused since there is room for another PCIe socket. Soldering quality is fine on the other side.


Soldering quality is good overall on the main PCB. Under the +12V islands, we spotted four current shunt resistors, matching the number of virtual +12 V rails that this PSU has.


The cooling fans are provided by Protechnic Electric. Its model number is MGA12012HF-A25 (12V, 0.45A, 2400 RPM, 84.8 CFM, 37 dBA, 155g). The same fan is used in the Gold AURUMs.