Component Analysis

Before reading this page, we strongly suggest a look at this article, which will help you understand the insides of a PSU better.



CWT's GPR platform in its basic configuration is used. Build quality is high since most electrolytic caps are rated at more than 4,000 hours life, and next to them, a lot of polymer caps are used for ripple-filtering purposes. Ideally, I would like to see Infineon or Vishay FETs everywhere, and a stronger boost diode capable of handling up to 8 A, just in case. The primary side consists of a half-bridge topology along with an LLC resonant converter. On the secondary side, we find synchronous rectification and a pair of DC-DC converters for the minor rails.


The transient filter has all the required parts, but EMI suppression is not that good.


An MOV provides protection against voltage surges. Inrush current protection is handled by an NTC thermistor, which is supported by a bypass relay.


The bridge rectifiers have a very high recurrent peak reverse voltage rating and are powerful.


The PFC converter uses two Great Power FETs; their voltage rating is below what we usually see. This won't be a problems, though, since the bridge rectifiers output less than 375 V in even the worst-case scenario (264 V input). What worries me a bit is the at 6 A rather weak boost diode. I would like to see an 8 A diode. Lastly, the bulk caps are by Nichicon and of sufficient capacity for a 750 W power supply.


The APFC controller is a Champion CM6502. The latter is supported by a CM03X by the same brand, which reduces no-load power consumption—also called phantom or vampire power—by cutting energy flow to the APFC converter when the PSU is in standby mode.


The main transformer has the CWT name in its model description. As you can see in the photos above, it is directly connected to the board that hosts all the FETs that generate the +12 V rail.


Most of the electrolytic caps belong to good lines of Japanese brands. A large number of polymer caps are also used for ripple-filtering purposes.


The VRMs that regulate the minor rails are installed on the same board. Four UBIQ FETs are used, and the common PWM controller is a ANPEC APW7159.


This is the transformer of the 5VSB regulator. On the primary side of this circuit, we find a UTC 4N65L FET, while an S10P45U SBR handles the secondary side.


The supervisor IC is a Sitronix ST9S429-PG14; it supports all important protection features but OTP (Over Temperature Protection), which is implemented through another circuit.


CWT usually doesn't let me down when it comes to soldering quality, and this PSU is no exception.


Here are some close-up shots of various parts of the PCB with the SBRs, optocouplers, SMD resistors, and caps.


The fan consumes a lot of power and uses ball bearings, while most competing offerings feature FDB or rifle-bearing fans. Ball-bearing fans cope with high operating temperatures better, but produce more noise. I prefer a DBB fan over a lower-quality sleeve or rifle-bearing fan any day of the week.