A Look Inside

Before reading this page we strongly suggest to take a look at this article, which will help you understand the internal components of a PSU much better.


From the ultra long fins of the headsinks and the black and white power wires someone can easily find out the OEM of this unit, which of course is Enhance Electronics, the favorite manufacturer of Silverstone. The unit utilizes a two power switch Active Clamp Reset Forward (ACRF) topology in the primary side to achieve Gold efficiency; exactly the same topology is used in the Cooler Master Silent Pro Hybrid 1050W which also is made by Enhance. In the secondary side we meet the usual setup for a Gold efficiency PSU: synchronous design and DC-DC converters for the minor rails generation.


As we use to do in every PSU review we will start the internal analysis from the transient filtering stage. This starts right from the AC receptacle with two pairs of X and Y caps. On the main PCB we also find two pairs of X and Y caps, two CM chokes and an MOV. A pretty complete EMI (or transient) filter.


The single bridge is sandwiched between the primary and a smaller heatsink. This time we didn't feel that we had the courage to fight with these tough Enhance heatsinks so we left them in place. After all we managed to easily identify all crucial parts without much desoldering. We missed only the bridge rectifier which most likely can handle up to 25A in this case.


After the bridge rectifier there is the PFC input capacitor which filters the high frequency ripple and a huge PFC choke. Next to the choke resides the thermistor responsible for inrush current protection. Strangely enough, for a Gold PSU, there is no relay to bypass it once it finishes its job so a small amount of energy is wasted on it.


In the APFC two SPW35N60C3 fets are used along with a boost diode. The hold up caps are two parallel Chemi-Cons (330µF, 450V, 105°C, KMR series).


As we already stated on the beginning of this page, the topology used to achieve Gold efficiency is the Active Clamp Reset Forward one. Usually in this topology one chopper switch is only used but in this case, since the capacity is 1kW, two main switchers are used. The primary choppers are two IPW50R140CP fets and the reset switch is an FQPF3N80C.


On the vertical PCB, right behind the modular one, many interesting components are soldered so let's take a look at them. On the right side the larger IC is the famous CM6802S combo PFC/PWM controller and the IC on the left of it is a UC2715D complementary switch FET driver, used by the ACRF topology. This IC provides the zero voltage switching ability to the main choppers, which greatly increases efficiency. In the middle of the PCB there are two optocouplers which isolate the two circuits. On the left side the protections IC, a PS232S, is soldered. This IC provides OCP for up to four +12V rails and has no integrated OTP but provides an additional protection input pin so the OTP signal passes through this pin to the control IC. Also on the fins of the secondary heatsink we find two thermistors wrapped in heatshrink, the left is for the fan speed control while the right is for OTP.


The standby PWM controller, an STR-A6000 IC, is hidden under the primary heatsink.


In the secondary side four IPP023N04N mosfets regulate +12V and afterwards from this rail and with the help of two DC-DC converters, the minor rails are generated.


On the PCBs of the VRMs we find several polymer caps while all electrolytic caps in the secondary side are provided by Nippon Chemi-Con (105°C, KZE series).


On the front side of the modular PCB there are some extra filtering caps from Suncon (SUN Electronic Industries Corporation), a Japanese company. The rear side features good, but not top, soldering quality.


On the main PCB soldering quality is not up to the levels that we are used to see from Enhance. We spotted several hand made blobby solder joints in the secondary side. Also as you can see in the last of the above photos, this PSU originally had four +12V rails (look at the four shunts) which in this case were shorted, rather rough, with a thick wire to form a single rail.


The high quality cooling fan is provided by Silverstone and belongs to the Air Penetrator series. Its model number is HA1425M12F-Z (12V, 0.36A) and besides Fluid Dynamic Bearings (FDB) which promises prolonged lifespan it utilizes a unique blade and grille design which, according to Silverstone, is able to create enough pressure to push air as far as one meter away with minimal fan speed and noise.