A Look Inside & Component Analysis

Before 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 of disassembly is a Thermaltronics TMT-9000S soldering and rework station. It is of extreme quality and is equipped with a matching de-soldering gun. With such equipment in hand, breaking apart every PSU is like a walk in the park!


This is a new platform from FSP, and it utilizes a modern design with an LLC resonant converter in its primary side and a synchronous design with DC-DC converters for the generation of the minor rails in its secondary side. After opening the PSU, we instantly noticed the CT board with several caps and a small transformer, right next to the main transformer. There are only two small heatsinks without any components in the secondary side. These dissipate the heat the +12V fets on the obverse side of the main PCB produce. The chassis also plays an important role in dissipating the heat these fets generate, a technique we come across quite often in highly efficient PSUs.


An X and two Y caps at the AC receptacle form the first part of the EMI filter. The same filter continues on the main PCB with an X and two Y caps, two CM chokes, and an MOV. Although the EMI filter includes all the necessary components, it still doesn't do a good job since there is an excessive amount of EMI at low frequencies.


Inrush-current protection is handled by an NTC thermistor and its relay that allows it to cool down faster.


The single bridge rectifier is bolted to the APFC's heatsink.


A single STTH12R06FP boost diode and two STF18N60M2 fets are used in the APFC converter. All these parts are provided by STMicroelectronics. The bulk caps are two parallel Chemi-Cons (420V, 105°C, KMR) with a combined capacity of 660uF. Although their capacity doesn't look high for a 750 W unit, our test result show that they get the job done.


A small board holds the APFC controller, an Infineon ICE2PCS02 IC. We found two more ICs at the front—two op-amp amplifiers, a TS358CD and an LM393.


The main switchers are two STMicroelectronics STFI26NM60N fets.


The 5VSB circuit is rectified by a dedicated circuit housed on the board shown above. The PWM controller is a Power Integrations SC1226K, and the fet that regulates the rail is an IRFR1018E by International Rectifier. This board does a terrific job, and the HG750 has one of the more efficient 5VSB circuits we have come across thus far. FSP set an example other OEMs should follow up on with its 5VSB circuit.


The +12V fets, two Toshiba TPHR8504PLs, are on the solder side of the mainboard. The heat these fets produce is dissipated through a heat-pad attached to the PSU's enclosure, and a copper board on top of the PCB with a couple small heatsinks right above it. As you will have noticed by taking a look at these photos, the TPHR8504PL fets don't look like typical ones since they have eight pins instead of the three most fets have.


The LLC resonant controller is a Champion CM6901 on a board right behind the modular PCB. On the same board are three op-amp amplifiers, a TS358CD, an LM393NG, and an LM359. The LM359 is behind a series of Chemi-Con caps.


The electrolytic filtering capacitors are by Chemi-Con (KZE and KY series), and we also found few Rubycons. All are rated at 105°C and will last for a long time. The polymer caps aren't made by a Japanese company, but Teapo, a Taiwanese company with a good reputation. Since polymer caps last much longer than electrolytic ones and can operate at very high temperatures without any problems, we won't whine about these Teapo caps.


A daughter-board hosts both DC-DC converters that generate the minor rails. The common PWM controller is an Anpec APW7159C, and a total of six IRLR8726PbF fets are used by both rails.


Another vertical board houses the protections IC, a SITI PS223. This IC is one of the very few with support for OTP (Over Temperature Protection) out of the box.


Several Teapo polymer caps and a couple electrolytic Chemi-Con caps on the modular PCB are there for ripple-filtering purposes. A large number of bus-bars at the bottom of this board connect it to the mainboard, which minimizes the amount of power that is wasted on power transfers, especially at higher loads.


Soldering quality is good overall; however, we spotted some long component leads, which we hate to see as such leads can cause dangerous shorts.


The fan was the only part that didn't survive this review since we had to figure out whether it is a true FDB fan, as FSP claims. Its internal spiral grooves in the last photo prove that it is an FDB fan.