A Look Inside & Component AnalysisBefore reading this page, we strongly suggest a look at this article, which will help you understand the internal components of a PSU better. Our main tool for the disassembly of the PSU is a Thermaltronics TMT-9000S soldering and rework station. It is of extremely high quality and is equipped with the matching soldering gun. With such equipment in hand, breaking apart every PSU is like a walk in the park!
FSP is the OEM that built the platform that this unit exploits, and we were left speechless once we removed the top of the case. The main PCB is way under-populated. We could easily assume that this PCB belongs to a 500-600 W PSU if we didn't know the true capacity of the unit. FSP apparently managed to shrink all components needed by such a high capacity unit while also reducing heat dissipation greatly, since all heatsinks are really small. As for the design this platform exploits, the primary side doesn't use an LLC resonant converter, although it is heavily utilized by the competition. The secondary side uses a synchronous design for the rectification of the +12V rail and a custom designed IAC-DC circuit for the generation of the minor rails. As you can see, the white colors even dominate the internals of the PSU, giving it a very clean internal look. All of its components can easily be distinguished against such a white background.
The transient filter starts right at the AC receptacle. In this case, it includes one X and two Y caps. The latter is supported by a CM02X IC, which blocks current through the cap's discharge resistor when AC voltage is connected and automatically discharges the cap through the discharge resistor when AC is disconnected. This offers an efficiency boost, since no energy is wasted on the bleeding resistor once power is turned on. On the main PCB, we find the other parts of the transient filter: two CM chokes, one X and two Y caps, and an MOV. We also spotted another CM02X IC on the solder side of the PCB.
The two parallel bridge rectifiers are bolted onto a dedicated heatsink. Their model number is D15XB60 and each one can handle up to 15 A of current. In front of the bridge rectifies resides the thermistor that offers protection against large inrush currents, and the relay that cuts it off the circuit once it finishes its task.
In the APFC section, three Infineon IPA60R165CP fets are used along with two STTH8R06FP boost diodes. The hold-up caps are two parallel Nippon Chemi-Con ones (450 V, 220 μF, 105°C, KMR series). Their combined capacity (440 μF) looks small for a 1 kW unit but FSP seems to have optimized the design, since the hold-up time exceeds the ATX spec limit (16 ms). Finally, the PFC/PWM controller is the FSP 6600 IC for which we didn't find any documentation online.
The main switchers are arranged in a three power switch Active Clamp Reset Forward (ACRF) topology, which allows for high efficiency without the use of an LLC resonant converter. This is the first time we meet an ACRF topology with so many primary switchers (SPA11N80C3). The reset switch is the usual suspect: an FQPF3N80C fet.
Things are starting to get more interesting on the secondary side. The +12V rail is rectified by four Infineon IPP023NE7N fets that are cooled by a really small heatsink. Now, the minor rails are not generated through DC-DC converters by the +12V rail. Instead, they come from an AC-DC circuit. This means that a separate line feeds the corresponding rectification circuit with AC power, which results in these two rails that are independently regulated (the two small inductors of the secondary side are clear proof of this). Finally, all filtering caps on the secondary side are provided by Chemi-Con (KZE and KZH series, 105°C).
All mosfets that handle the minor rails are located on the solder side of the main PCB. In general, three 2R0640 (100 A, 40V), a single 2R030, and two 036N04 fets are used. The PWM controllers of the minor rails are two proprietary FSP 6601 ICs.
This daughter-board houses the protections IC, a Weltrend WT7527 IC that supports OCP for up to two +12V rails. However, this unit has a single +12V rail, which leaves the second channel unexploited. The three pots on the top of this board are probably used to adjust the thresholds of the available protections, so better not mess with those.
Not one but two fets that are cooled by small dedicated heatsinks rectify the 5VSB rail.
At the front side of the modular board, we find seven polymer Chemi-Con caps. They provide some extra ripple filtering. The same PCB is connected to the main one through several thick bus bars.
Soldering quality on the main PCB is quite good and all component leads are carefully trimmed. Good job, FSP. Our only objection is that they didn't use spade terminals for the connection of the AC receptacle with the PCB, so you need to desolder those cables in order to get a hold of the main PCB.
The cooling fan is provided by Protechnic and its model number is MGA13512YB-025 (12V, 0.5 A, 2100 RPM, 116.81 CFM, 42.0 dBA). It is definitively not the quietest fan out there.