Page 3 - Physical Look - Inside
As we usually do, we opened up the SilverStone ST45SF V3.0 450W power supply to take a closer look at what is going on inside. Opening up this power supply will void your three year warranty, as the warranty seal covers one of the chassis screws. For your benefit, we voided our warranty on this unit, so you do not need to. There are zero user serviceable parts inside anyway. Removing the top shell from the SilverStone ST45SF V3.0 450W is easy, as it requires four screws to be removed; one at each corner on the side. Afterwards, you can slide apart the top and bottom shells to get inside. The OEM for the SilverStone ST45SF V3.0 450W is High Power Electronic Co., Ltd/Sirfa, which is the same manufacturer as some other SilverStone units, including the SilverStone SX700-LPT 700W. The photo above shows an overhead view of its internal components. Build quality looks acceptable, even though there are some globs of glue to keep the parts in place. This OEM does not have the greatest reputation compared to other OEMs such as Enhance or Seasonic, but we will see how this affects the build. Otherwise, there are two large heatsinks and one smaller one, all of which are left in its silver color.
The transient filter stage is the first input stage of any computer power supply, so we will take a closer look at this first. From here, there are two ferrite coils, but no metal-oxide varistor. A single X-capacitor and two Y-capacitors are placed at the AC receptacle, while another X-capacitor and two Y-capacitors are found on the main board. In total, this is at least twice the required X- and Y-capacitors recommended, which is good to see. The missing MOV here is a big disappointment, as they are intended to protect your power supply from AC line voltage spikes. However, there is some input filtering in the form of a transient-voltage-suppression diode.
On the primary side, there is a single Nippon Chemi-Con capacitor rated at 330uF at 400V. It has a temperature rating of 105c. It is great to see a Japanese-made capacitor here, as some cheaper units have capacitors made in Taiwan or China. In addition, budget power supplies have primary capacitors rated at a lower 85c temperature. However, most of the secondary capacitors around this board are Teapo branded capacitors, which are more reputable than other Taiwanese companies, but still a step down from their Japanese counterparts.
The power supply uses one GBU1506 rectifying bridge attached to a heatsink, supporting up to 15A of current at 100C. At 115V, the theoretical power you can pull from the bridge rectifier is 1725W at 100% efficiency. Of course, this is purely from the bridge rectifier, and not all components in the power supply can actually hold this workload. Even so, this is well above the necessary requirements for a 450W power supply. The active PFC circuit in the SilverStone ST45SF V3.0 450W is located on an add-in card. The active PFC circuitry is handled by two Super Junction SPTA22N50A N-channel MOSFET. This transistor is rated to deliver 14A at 100 degrees Celsius continuously, with a maximum resistance of 0.23 ohm and a typical resistance of 0.13 ohm. The two switchers are Infineon 5R250P MOSFETs, with a drain to source voltage of 700V, continuous drain current of 11.3A at 100 degrees Celsius continuously with a maximum resistance of 0.25 ohm and a typical resistance of 0.23 ohm. These on characteristics are called Static Drain-Source On-Resistance or commonly abbreviated as RDS(on). The more efficient the component is, the lower the RDS(on) value, since it wastes less power with lower resistance. A single NXP BYC10 Hyperfast power diode is found in the active PFC circuit too.
As for the secondary side, there are quite a few more Japanese and Taiwanese capacitors made from Nippon Chemi-Con and Teapo for both the electrolytic and polymer capacitors. The electrolytic capacitors are all rated at 105c. As with modern high efficiency power supplies, all rectifiers produce the +12V out -- while the +5V and +3.3V outputs are generated from the +12V output using a DC to DC converter within the power supply unit. The +12V output is regulated by two PFC Device Corporation PFR30V45CTs attached to a large metal heatsink. Another daughterboard can be found with the DC to DC converters. These are the four Infineon BSC0906NS, with a rating of 40A at 100 degrees Celsius with a peak drain current of 63A. Drain to source voltage is 30V and an RDS(on) value of only 0.0045 ohms. An ANPEC APW7159 dual channel synchronous buck PWM controller can be found here too. Finally, a Champion CM8606 PWM controller and a Weltrend WT7527V protection IC can be found together. The datasheets for all components mentioned in this review can be found on their respective manufacturers' websites.
Finally, you can see where all the cables are connected and sleeved to lead outside of the SilverStone ST45SF V3.0 450W. There is nothing too special here, other than the fact there are a lot of cables running around here. The compactness of this SFX unit is one of the main reasons why this unit is a lot harder to build or inspect, but I have to say SilverStone and High Power have done a good job in ensuring quality is not sacrificed here. Soldering is relatively good, which is even more crucial on a smaller board like this. Component selection too is quite acceptable with a decent layout for cooling. Some parts are pretty close together, but the many numbers of heatsinks should help. Obviously, with a form factor like the SFX size, cooling is even more important.
Speaking of cooling, the last component to look at is an important one, as it draws in air to let all these small components breathe easy. This is a Globe Fan Duro Bearing 92mm fan, connected to the mainboard of the power supply. Marketing aside, the Duro Bearing is just a fancy name for sleeve bearings, which should offer quieter operation. Further research of the Globe Fan S0921512H let me find out it operates at 12V and 0.23A, and has a maximum speed of around 3000RPM. The rated air volume is 32.2CFM at a noise level of 29dB.
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion