Page 3 - Physical Look - Inside
As always, we opened up our SilverStone Strider Essential Gold ST70F-ESG 700W power supply to take a detailed look at what is going on inside. Please note that doing this at home will void your 1-year warranty, thanks to the warranty seal SilverStone applied over one of the attachment screws. But for the benefit of you, we cracked ours open so you don't need to, haha. There are no user serviceable parts inside. Not to beat a dead horse, but as I have mentioned earlier, one year warranty is rather short for a power supply. I have never had issues with SilverStone products, but a longer warranty usually provides a little more assurance to the end user.
Disassembling the SilverStone Strider Essential Gold ST70F-ESG 700W is quite straightforward, with the removal of four screws on the side. When I first saw at the warranty seal, it looked very familiar. Where have I seen it before? After taking a look at the inside, it all came together. The ST70F-ESG has a design with striking resemblance to the FSP AURUM Gold 600W I have reviewed three years ago. Our photo above shows an overhead view of its internal components. Clearly, FSP is the OEM; all doubts were removed when I looked up the UL code. Needless to say, the interior is remarkably simple, as FSP has spent a considerable amount of time developing the AURUM Gold platform in order to reduce as many components as possible. While other PSUs I have seen in the past are usually quite packed up, the Strider Essential Gold does not have too much going on here. Not only that -- there is only one small black painted main heatsink plus two smaller ones adjacent to it, as shown in our photo above. This simple heatsink arrangement along with a loosely packed interior has a lower airflow impedance benefit, so SilverStone is able to get away with a slow running 120mm fan. We will see how quiet the Strider Essential Gold is on the next page, but for now, I am not going to waste any of your time -- let's take a closer look.
The transient filter stage is the first input stage of a computer power supply, so we'll take a look at that first. SilverStone met or exceeded the recommended requirements accordingly, other than the notably missing is the metal oxide varistor, otherwise known as the MOV. The MOV is used to stabilize spikes from the AC line. FSP, the OEM, claims this is not necessary due to the MIA IC's over voltage protection system (More on the MIA IC in just a second), which already absorbs excess surge from the AC line on the primary side to protect the buck capacitor. The SilverStone Strider Essential Gold has three ferrite coils, two metalized polyester X-capacitor, and four ceramic Y-capacitors. That is twice as many X and Y capacitors and one more ferrite coil than recommended; everything else is just standard. For a power supply of this caliber, this is about what I have expected, and it certainly gets the job done right.
On the primary side, our SilverStone Strider Essential Gold ST70F-ESG 700W incorporates one Rubycon capacitor rated at 390µF x 450V. If you have a model with different rated wattage, chances are that this value will be different. As with all quality power supplies, this capacitor is rated at 105c; whereas low end power supplies usually settle with 85c rated capacitors.
A close inspection of the PCB will reveal 600W, 650W, and 700W variants can be built on the same baseboard. There is no 650W version of the Strider Essential Gold, but SilverStone does sell a 600W unit. The difference comes down to mainly the PFC Choke and capacitor on the primary side, and MOSFETs on both the primary and secondary side. The active PFC circuit featured on the SilverStone Strider Essential Gold ST70F-ESG 700W uses one Lite-On Semiconductor GBU1506 bridge rectifier, and is controlled by a FSP6600 PFC/PWM controller combo. At 115V, the maximum rectified forward current capacity with heatsink is 15A, so you can theoretically pull up to 1725W (15A * 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. Two Infineon IPB60R125CP power MOFSET transistors are used on the active PFC circuit on the SilverStone Strider Essential Gold ST70F-ESG 700W power supply, with a STMicroelectronics STTH8R06FP Turbo 2 ultrafast high voltage rectifier. Adjacent to the aforementioned is a Fairchild Semiconductor FQPF3N80C MOSFET and Infineon Cool MOS SPA17N80C3 power transistor. On the other side of the heatsink, we can spot a CET CEF02N7 N-channel enhance mode field effect transistor. Each Infineon IPB60R125CP can deliver up to 16A at 100 degrees Celsius continuously. These transistors present a maximum resistance of 0.125 ohm when turned on; with a typical resistance of 0.110 ohm according to the manufacturer's data sheet. The Infineon SPA17N80C3 can deliver up to 11A at 100 degrees Celsius continuously; with a maximum resistance of 0.29 ohm, and a typical resistance of 0.25 ohm. This on characteristic is 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.
One of the biggest highlights of the AURUM Gold platform the ST70F-ESG is built upon is what FSP refers to as the Active Clamp Topology and Multiple Intelligence Ability, or MIA IC. The MIA IC is a multi-function integrated circuit. Working in conjunction with its Active Clamp Topology, this allows a large reduction in physical components; and FSP claims large strides in AC to DC conversion efficiency. We have no question about the former; it is evident right from the pictures above. The latter is achieved with zero current switching and zero voltage switching between the AC input and DC output.
On the secondary side, we see capacitors made by United Chemi Con, all rated at 105c. Two International Rectifier IRLB3036GPbF MOSFETs located on the small silver heatsink are responsible for the rectification process. As with modern high efficiency power supplies, all rectifiers produces 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 IRLB3036GPbF's rated continuous drain current is 190A at 100c, and a pulsed drain current of 1100A. Drain source voltage is rated at 60V, and a RDS(on) value of only 0.0019 ohm.
The DC-to-DC converter is controlled by one proprietary FSP6601 integrated circuit chip and four Infineon OptiMOS 3 IPD031N03L power transistors for its +3.3V and +5V outputs. The IPD031N03L's rated continuous drain current is 90A at 100c, and a pulsed drain current of 400A. The RDS(on) value is rated at 0.0031 ohm maximum, and 0.0026 ohm typical. Meanwhile, a Weltrend WT7527 monitoring IC provides the Strider Essential Gold ST70F-ESG's OVP, UVP, and OCP protection. The datasheet for this chip can be found on the manufacturer's website.
Lastly, we see a 120mm fan that provides cooling to the SilverStone Strider Essential Gold ST70F-ESG 700W's internal components. It is permanently soldered to the mainboard using a 2-pin connector. A 120mm fan is rather small nowadays for a power supply with a bottom mounted fan, but if not a lot of heat is being generated, it should not be much of an issue. A 120mm fan is used to keep the enclosure as small as possible. Yate Loon is the fan OEM, with D12SH-12 as the model number, as shown in our photo above. Further research indicates the D12SH-12 is a hybrid ceramic ball bearing fan specified at 0.30A for a maximum of speed of 2200 rpm. The rated airflow is 88.0 CFM at 40 dB of noise. This is a higher speed with revised hybrid ceramic ball bearing version of the D12SM-12 used in the FSP AURUM S 600W reviewed by my colleague Kenneth Kwok in December 2013.
Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion
