Channel Well Technology CSX 850M-G Review - The first PCIe 5.0 ready SFX PSU

Name: Channel Well Technology CSX 850M-G
Brand: Channel Well Technology

crmaris

on Sep 2nd, 2022,

in Power Supplies.

Manufacturer: Channel Well Technology

Voltage Regulation Stability & Ripple »

Component Analysis

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

CWT CSX 850M-G Parts Description
General Data
Manufacturer (OEM)	CWT
Platform	CSX
PCB Type	Double Sided
Primary Side
Transient Filter	2x Y caps, 4x SMD Y caps, 2x X caps, 2x CM chokes, 1x MOV
Bridge Rectifier(s)	2x GBUE2560 (600 V, 25 A @ 140 °C)
Inrush Current Protection	NTC Thermistor (SCK-037) (3 Ohm) & Relay
APFC MOSFETs	1x Infineon IPW60R045P7 (600 V, 38 A @ 100 °C, Rds (on): 0.045 Ohm) & 1x Sync Power SPN5003 FET (for reduced no-load consumption)
APFC Boost Diode	1x On Semiconductor FFSP1065B (650 V, 10 A @ 139 °C)
Bulk Cap(s)	1x Rubycon (420 V, 470 uF, 3,000 h @ 105 °C, MXK)
Main Switchers	2x Vishay SiHA105N60EF (600 V, 8 A @ 100 °C, Rds (on): 0.102 Ohm)
APFC Controller	Champion CM6500UNX
Switching Controller	Champion CU6901VAC
Topology	Primary side: APFC, Half-Bridge & LLC converter Secondary side: Synchronous Rectification & DC-DC converters
Secondary Side
+12 V MOSFETs	6x International Rectifier IRPH7004PbF (40 V, 164 A @ 100 °C, Rds (on): 1.4 mOhm)
+5 V & +3.3 V	DC-DC Converters: 2x UBIQ QM3054M6 (30 V, 61 A @ 100 °C, Rds (on): 4.8 mOhm) & 2x UBIQ QN3107M6N (30 V, 70 A @ 100 °C, Rds (on): 2.6 mOhm) PWM Controller(s): uPI-Semi uP3861P
Filtering Capacitors	Electrolytic: 2x Elite (2 - 5,000 h @ 105 °C, ED series), 1x Chengx (2 - 4,000 h @ 105 °C, GR series) 2x Chengx (3 - 6,000 h @ 105 °C, LF series) Polymer: 7x APAQ, 9x CapXon, 5x no info
Supervisor IC	Weltrend WT7502R (OVP, UVP, SCP, PG)
Fan Controller	8A08A2
Fan Model	Hong Hua HA9215SH12FD-F00 (92 mm, 12 V, 0.46 A, Fluid Dynamic Bearing Fan)
5VSB Circuit
Rectifier(s)	1x PS1045L (45 V, 10 A) SBR
Standby PWM Controller	On-Bright OB2365T

This is a new platform by CWT, with the code name CSX. The primary heatsink is large enough; on the secondary side, there are no proper heatsinks, so the PCB doesn't look overpopulated. The design is up to date, and the components that CWT use are of decent quality. You can ask for better caps on the secondary side to replace those ChengX ones if your budget allows it. The problem is that it is tough to find good caps at fair prices during this period because of the vast stock shortages.

The transient filter is complete.

There is an MOV for protection against power surges. An NTC thermistor handles inrush currents. It is supported by a bypass relay.

The two bridge rectifier can handle up to 50 A!

The APFC converter uses a single, powerful Infineon FET and a strong boost diode. Lastly, the bulk cap is Rubycon, and is of high quality.

CWT installed a FET to isolate the APFC converter once the PSU is in standby mode, to reduce vampire power.

The primary switching FETs are installed into a half-bridge topology. The choke shown in the second photo is the resonant tank.

The resonant controller is a Champion CU6901VAC, which supports kick (burst) mode operation, for high efficiency even at very light loads.

The board holding the +12 V FETs is installed next to the main transformer for minimized energy losses.

I don't have a problem with Elite caps. On the contrary, I am not fond of the ChengX ones. This is an OEM platform, though, and the client brands can ask for any changes in parts, especially in filtering caps, which can notably affect production cost.