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.


As we already mentioned in the introduction, the OEM of the new Commanders is Andyson and the platform is rather modern since it utilizes synchronous design in the secondary and it has DC-DC converters for the minor rails generation. Not to long ago these characteristics could only be found in high-end units!


The transient filter starts right at the AC receptacle with one X and two Y caps. It continues on the main PCB with two CM chokes, an MOV, one X and two Y caps. All essential components are here as you can see. The bridge rectifiers, two parallel GBU805, are bolted together on a heasink. Right in front of them we find the PFC input capacitor that filters the high frequency ripple of the rectified 100 Hz output (with 230V/50Hz power input) and the current sense resistors used by the APFC controller.


The APFC mosfets are two SPW21N50C3 and the boost diode is an STTH15R06D. On the left of the boost diode there is the thermistor responsible for the inrush current protection during the start up phase of the PSU. The two parallel hold up capacitors are provided by Matsushita/Panasonic (400V, 330μF each and 660μF total, 105°C).


The main switches are two SPW21N50C3 in the traditional double forward topology.


The combo PFC/PWM controller is the famous CM6800. The latter is soldered on a vertical daughter-board in the primary side.


Housekeeping duties are handled by a PS232S protections IC which supports OCP for up to four +12V rails, so it covers the unit's specifications.


In the secondary there aren't any passive components (SBRs), something that greatly benefits efficiency. So the +12V are generated by three IRFB3306G mosfets. The minor rails are handled by two DC-DC converters which are wrapped in plastic, in order be isolated from the other components and minimize EMI. Besides the polymer caps used in the two VRMs all other are electrolytic and provided by Teapo (rated at 105°C), one of the most reliable Chinese caps manufacturer.


In the front of the modular PCB there are five polymer caps for further ripple filtering. Very good choice that indeed helps in ripple suppression.


Soldering quality is quite good with clean and well made solder joints. Also we did not spot any long component leads, something that greatly pleased us. Finally in the +12V area we spotted four shunt resistors, which measure the current drawn by each +12V rail providing vital information to the OCP.


The cooling fan is provided by Young Lin Tech Co. and its model number is DFB132512H (12V, 3W, 1700RPM, 91.16CFM, 36.28dBA).