Corsair HX850 V2 850 W 18

Corsair HX850 V2 850 W

Voltage Regulation & Efficiency »

A Look Inside

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


The OEM of this unit is CWT, and this is easily revealed, at least to the experienced eye, by the green-colored transformers. The platform is new, and a stripped version of it is used in the Thermaltake Smart 750W and the Corsair GS800 V2 units that we had reviewed previously. On the primary side, a plain topology without an LLC converter is utilized, while on the secondary side we find synchronous rectification along with two VRMs for the generation of the minor rails. The VRMs are installed directly on the modular PCB for lower voltage drops and less energy waste.


On the AC receptacle, there are two Y caps, and on the main PCB, we find the rest of the components of the transient filter, namely, two pairs of X and Y caps, two CM chokes, and an MOV.


The two parallel bridge rectifiers (GBU 1006) are bolted on a dedicated heatsink.


In the APFC two IPW60R099C6 FETs are used along with a CREE C3D06060 boost diode. To provide you with a better view, we removed the heatsink that holds the aforementioned diode. Finally, the two parallel hold caps are provided by Nippon Chemi-Con (390 μF, 420 V, 105°C, KMR series).


The main switchess are two IPW60R190E6 FETs, and right next to them, we find the thermistor, which is responsible for protection against large inrush currents, and a relay which bypasses it once the start-up phase finishes.


The combo PFC/PWM controller is a Champion CM6802, which is an upgraded version of the famous CM6800, offering higher efficiency.


On the secondary side, synchronous rectification is used and the +12 V rail is rectified by six FETs. The small vertical PCB that houses all the aforementioned FETs doesn't have a heatsink attached, which could help remove the heat, but on its rear side there are three thick solder traces that assist in heat dissipation. All +12V filtering electrolytic caps on the secondary side are provided by Chemi-Con (KY series) and are rated at 105°C. Besides the electrolytic caps, we found also some polymer Enesols.


The two VRMs that generate the minor rails are located on the modular PCB in order to eliminate the need for power cables, for the transfer of these two rails to the modular sockets at least. This means lower voltage drops and higher efficiency since much less energy is dissipated on the wires. The common PWM controller for both VRMs is an APW7159, and for each minor rail four 72T03GH FETs are used. At the front of the modular PCB, we find many polymer filtering caps. The big ones with the pink markings are from Enesol, while the smaller blue ones are from an unknown brand.


Housekeeping duties are handled by a Weltrend WT7502 IC which doesn't support OCP, a needless protection anyway for a single +12 V rail PSU of such high capacity.


Soldering quality on the main PCB is very good and up to the levels that we are used to seeing from CWT. On top of that, all component leads are carefully trimmed so they won't cause any trouble.


The cooling fan is provided by Hong Hua and uses double ball-bearings, so it will last quite long. Its model number is HA1425H12B-Z (0.50 A, 12 V DC) and at normal ambient temperature is quiet enough.
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