FSP Hydro PTM 750W (Page 3 of 4) | Reports

Page 3 - Physical Look - Inside

In order to further investigate the design details of the FSP Hydro PTM 750W power supply unit, some panel removal is required. It is important to note two important concerns before disassembling any power supply unit: First, certain components, such as the capacitors, may cause an electrical shock; and second, your ten-year warranty will be voided if the screws on the power supply unit are removed. Therefore, unnecessary disassembling of a power supply unit should be avoided. Once the top panel of the Hydro PTM is removed, a closer look of the electronic components can be revealed. The OEM for the power supply is FSP.

Let us first take a look at the transient filter stage of the power supply unit. The function of the transient filter stage is to protect the computer from the power grid noise and voltage spikes. In the FSP Hydro PTM 750W power supply unit, the transient filter stage contains a couple of X-capacitors, bunch of Y-capacitors, several ferrite coils, and one metal oxide varistor. The MOV here is to prevent the computer from being damaged by lightning surges. It is worth mentioning not all the power supply units in the market have an MOV. There are two sets of X-capacitors and Y-capacitors, with one set on the PCB board behind the power plug and the other set found on the main PCB board.

Now, we move on to the primary side. The two big capacitors in the photo are Rubycon capacitors, which are rated at 330uF at 420V each. The temperature is rated at 105c, which is the standard in terms of durability. They are Japanese brand capacitors, therefore it may have a higher cost, but the quality would be better compared with the capacitors made in other countries. For the standby 5V PWM control, there is a Power Integrations SC1226K chip. On the right hand side of the two capacitors, there are also three Toshiba TK20A60W ICs attached to the heatsink panel. As for power efficiency’s perspective, the Toshiba TK20A60W features 0.13 ohms drain-source on-resistance. Note the lower the drain-source on-resistance, the more efficient the transistor will be.

In the above photo, we can see there is a small heatsink above the two capacitors. There is a rectifying bridge attached to that heatsink. From what I can see, the rectifying bridge is a GBJ2506. At 115V, the maximum rectified forward current capacity with heatsink is 25A, so you can theoretically pull up to 2875W (25A * 115V) from the bridge rectifier at 100% efficiency -- of course, this is limited by the fact that it is not 100% efficient, and also neglects the fact that not every component in the system are able to keep up. On the right side of the photo, there is a PFC control board located above the big heatsink of the PFC converter. The IC on the PFC controlling board is the Infineon ICE2PCS02. Other components on the PFC control unit, especially those ones on the side of the board that is facing the big ferrite coil, are hard to recognize since there is no clear line-of-sight.

The electrolytic capacitors on the secondary side are also manufactured in Japan, and they are rated at 105c. These polymer capacitors are not from any Japanese company though; they are actually made by Teapo from Taiwan. For a modern power supply unit, the power output from the rectifiers is +12V. The +12V output of the power supply unit can just directly use the power from the rectifiers; however, the +5V and +3.3V outputs are converted from the +12V output. The conversion functionality is mainly realized by the components on the DC-DC daughterboard, where you can find an ANPEC APW7159C synchronous buck PWM controller and six Infineon BSC0901NS handling the +5V and +3.3V outputs. More information about these parts can be found from their respective datasheets from the manufacturer's website.

The modular cable sockets are soldered onto another daughterboard in the rear of the power supply unit. Having good soldering quality of those sockets is very important, since a significant amount of force will be applied on them when plugging or unplugging the connectors. The sockets in the FSP Hydro PTM 750W have very good soldering quality, and I am sure that they can handle some abuse with no problem. In the above photo, you can see a smaller board behind the sockets' daughterboard to hold the Silicon Touch PS223 protection IC.

In terms of cooling performance, there are two things we need to pay attention to for a power supply unit; namely the heatsink and cooling fan. In this case, we can see more than one heatsink and one cooling fan inside of the FSP Hydro PTM 750W. The number of heatsinks inside the power supply unit is abundant thanks to the roomy chassis. The size of the fan is 135mm in diameter, which is the maximum the enclosure can accommodate. According to the label on the fan, the MGA13512XF-A25 from the Protechnic Electric uses fluid dynamic bearings to keep noise and durability in check.

Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion