Xilence XQ Series 850 W 7

Xilence XQ Series 850 W

Voltage Regulation & Efficiency »

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.


We had to remove 14 screws to reach the main PCB. Unfortunately Xilence didn't make this PSU reviewer friendly! The first impression was made by the really small heatsinks on the secondary and the specially designed main transformer which incorporates the +12V fets. The platform includes many modern characteristics and more specific it uses an LLC resonant converter, synchronous rectification on the secondary and the VRMs responsible for the minor rails generation are close to the modular PCB, to restrict power losses. Finally the OEM of this unit looks to be Solytech.


The transient filter starts on the main PCB and includes two pairs of X and Y caps, two CM chokes, a thermistor and a relay to bypass it once the start up phase finishes and finally an MOV. The two parallel bridge rectifiers are two GBU15L06 and each one can handle up to 15A of current. To identify them we had to remove the PFC input capacitor.


In the APFC three STP25NM50N fets are used along with a C3D06060 boost diode. The two parallel hold up caps are provided by Samxon (330μF, 450V, 105°C), Solytech's favorite capacitor manufacturer. Personally we would highly prefer the use of Japanese caps in such a high priced PSU. As main choppers two STP25NM50N are used.


The main transformer uses a special design which allows the +12V fets to be directly attached to it, something that minimizes energy losses thus boosts efficiency. In total eight IPP037N08N fets are used for the +12V regulation.


The VRMs responsible for the minor rails generation are located on the main PCB and very close to the modular PCB. Each utilizes an APW7073 PWM controller, installed on the solder side of the main PCB, along with four fets.


These four shunts are probably for OCP of the +12V rails. Since on paper there are five +12V rails, an equal number of shunts should exist. Also the protections IC, a SITI PS229, supports OCP only for one +12V rail so most likely OCP is implemented through another IC.


In the secondary side ten electrolytic caps, rated at 105°C, provided by YC (YANG-CHUN) along with many polymer ones (provided by X-CON/Samxon) filter the DC outputs. The electrolytic ones are used exclusively for +12V filtering.


The modular PCB is directly attached to the main PCB via seven bus bars. This way transfer-resistances are reduced and efficiency gets a boost.
Four thin wires transfer PG (Power Good signal), -12V, PS On and 5VSB to the modular PCB. We don't mind for the first three but we would highly prefer a shorter route (e.g. via a PCB trace) for the 5VSB.


Soldering quality on the rear of the modular PCB is quite good. The two wires shown in the photo above power the Power On LED.


Soldering quality on most parts of the main PCB is very good, but we also spotted several sloppy solder joints. Thankfully we were unable to find a single long component lead, something that means less trouble.


The two cooling fans are provided by Shenzhen Xin Wang Xin electronics and their model number is XWX0615H12B (12V, 0.14A). Despite their small diameter they are pretty quiet since most of the time they operate at reduced RPMs.
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