Component Analysis

Before reading this page, we strongly suggest a look at this article, which will help you understand a PSU's internals better.



This is a high-end CWT semi-digital platform several expensive Thermaltake Toughpower PSUs also utilize. Because of its compact dimensions, the PCB is loaded with components, which means airflow is not optimal as there isn't much clearance between components. Still, CWT used small heatsinks, especially on the secondary side. The build quality is good, all electrolytic caps belong to good lines.


The EMI/transient filter has all the necessary components, but the digital circuits emit lots of EMI, which the EMI filter cannot handle.


An MOV in the transient filter handles power surges, and an NTC thermistor and relay combo take care of the large inrush currents during the PSUs start-up phase.


Two bridge rectifiers are installed in parallel on a dedicated heatsink.


An interleaved APFC converter is used, with two PFC circuits operating in parallel with a phase difference between them. This minimizes input and output current ripple and lowers conduction losses, which increases efficiency and doubles the effective switching frequency.


The four main switching FETs are installed in a full bridge topology. Two driver ICs are installed on the digital PCB. They are used for controlling the aforementioned FETs.


This is where the magic happens. Two Texas Instruments UCD3138A MCUs on this PCB take care of the whole primary side and the most important part of the secondary side, which is the circuit that generates the +12 V rail.


An APL1117 voltage regulator with 1 A max output. It most likely provides the operating voltage to the two MCUs.


The board that hosts the +12 V FETs is right next to the main transformer, and two thick, ultra-short cables are used for its connection to minimize energy losses. The heatsinks on this board are small, but the corresponding FETs can operate at high temperatures without any problems.


The filtering caps are of high quality, but they are squeezed between the modular PCB and the +12 V board, so the fan will have to spin at high speeds with high loads in order to keep their temperature low enough.


Both VRMs that handle the minor rails are installed on this board.


The 5VSB transformer and, right next to it, a vertical board that hosts the other parts of this circuit.


Lots of polymer caps have been installed on the modular board.


Soldering quality is pretty good, which is usually the case with high-end CWT implementations.


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