A Look Inside And Component Analysis
Before proceeding with this page, we strongly encourage you to a look at our PSUs 101 article, which provides valuable information about PSUs and their operation, allowing you to better understand the components we're about to discuss. Our main tools for disassembling PSUs are a Thermaltronics soldering and rework station, and a Hakko FR-300 desoldering gun.
|Manufacturer (OEM)||Fortech Electronics|
|Original Model||Segotep ZP500P-SG|
|Transient Filter||4x Y caps, 3x X caps, 2x CM chokes, 1x MOV|
|Inrush Protection||NTC Thermistor & Diode|
|APFC MOSFETs||1x Infineon IPW60R099C6 (650V, 24A @ 100°C, 0.099Ω)|
|APFC Boost Diode||1x SiC SCS210AG (650V, 10A @ 133°C)|
|Hold-up Cap(s)||1x Chemi-Con (400V, 330uF, 2000h @ 105°C, KMR)|
|Main Switchers||2x Fairchild FDPF20N50FT (500V, 12.9A @ 100°C, 0.26Ω)|
|Combo APFC/PWM Controller||Champion CM6502S|
|Topology||Primary side: Half-Bridge & LLC Resonant Controller Secondary side: Synchronous Rectification & DC-DC converters|
|+12V MOSFETs||4x Sinopower SM4021NA (40V, 100A @ 100°C, 1.6mΩ)|
|5V & 3.3V||DC-DC Converters: 4x Sinopower SM3116NAU (30V, 48A @ 100°C, 9.0mΩ) PWM Controller: 2x Anpec APW7073A|
|Filtering Capacitors||Electrolytics: Chemi-Con (1-5,000 @ 105°C, KZE), Chemi-Con (4-10,000 @ 105°C, KY) Polymers: Man Yue (Samxon) X-CON ULR, Enesol|
|Supervisor IC||Infinno ST9S313-SAG (OVP, UVP, SCP, PG)|
|Fan Model||Enermax ED142512W-CA (139mm, 12V, 0.25A, Twister Bearing)|
|Standby PWM Controller||Power Integrations TinySwitch TNY278PN|
As mentioned, this PSU is made by Fortech Electronics and appears to be based on the Segotep ZP500P-SG. The heat sink on the primary side is large enough for an efficient 80 PLUS Platinum unit, since it also hosts the pair of bridge rectifiers. The design isn't particularly clean, though; a lot of cables are used to transfer power to the modular board. Most modern designs don't use this many cables, if they have any at all. Rather, power is usually transferred through bus bars to the modular sockets. Eliminating those power transfer cables reduces energy losses and enhances the secondary side's cooling, since nothing blocks the air flow.
A half-bridge and LLC resonant converter are utilized on the primary side, while a synchronous design is used on the secondary side for the +12V rail, along with a pair of DC-DC converters for generating the minor rails. There are no large heat sinks on the secondary side, since the +12V FETs are installed on the PCB's solder side.
The PCB behind the AC receptacle hosts the power switch, along with two Y caps and a single X one. The EMI filter typically continues on the main PCB with two more Y caps, another two X ones, an MOV, and two CM chokes. The EMI filter is complete.
An NTC thermistor reduces the increased inrush currents, and a bypass relay isolates it from the circuit once its job is finished. This improves efficiency and cools the thermistor down faster so it can do its job when it's called upon.
The bridge rectifiers are bolted together on the primary heat sink.
Clearing a view to the APFC converter's parts required de-soldering the PFC choke and bulk cap. A single Infineon IPW60R099C6 FET and SiC SCS210AG boost diode shape the current's waveform to match the voltage waveform, bringing the power factor (PF) as close as possible to unity. The bulk cap is provided by Chemi-Con (400V, 330uF, 2000h @ 105°C, KMR), and although its capacity is low, it still enables a greater-than 17ms hold-up time. This clearly shows that, in addition to the bulk cap's capacity, a solid design also plays a crucial role in achieving the required hold-up time.
The APFC controller is a Champion CM6502S, installed on a small vertical board.
The primary FETs, two Fairchild FDPF20N50FTs, appear to be arranged in a half-bridge topology. If you're into aviation, then you're already familiar with Fairchild and its division responsible for manufacturing planes. Perhaps the most recognizable Fairchild-made plane is the A-10 Thunderbolt II, the tank-killer also known as "The Warthog".
The primary FETs are supported by an LLC resonant converter, which decreases switching power losses.
The LLC resonant controller is a CM6901 IC, installed on the PCB's solder side.
On the secondary side, four Sinopower SM4021NA FETs generate the +12V rail. Two small heat sinks above them, along with the PCB, cool the FETs down. Strangely enough, Fortech doesn't exploit the chassis' surface area to help draw heat away. It seems as though the Sinopower FETs are overkill for this unit's maximum capacity, so there's no need for additional cooling. Still, a thermal pad would have been cheap insurance against overheating.
The electrolytic filtering caps are provided by Chemi-Con and they belong to the KZE and KY lines. Besides electrolytics, polymer caps are also used. They're provided by X-Con (SamXon) and Enesol.
The standby PWM controller is a Power Integrations TinySwitch TNY278PN.
On the front of the modular board, several Enesol polymer caps provide an extra ripple filtering layer.
The soldering quality is mediocre. What troubles us most are the long component leads that we spotted in numerous spots on the PCB's solder side. Those can easily cause dangerous shorts. Fortech needs to upgrade its manufacturing line and quality control. In such an expensive PSU, we expected to find top build/soldering quality and nothing less.
The supervisor IC is a Infinno ST9S313-SAG IC, which only offers basic protection features.
The cooling fan uses a twister bearing, which, according to Enermax, lasts forever. Its model number is ED142512W-CA and it is incredibly quiet, since its maximum speed stays close to 1000 RPM. On top of that, the fan control circuit is especially conservative.