Bitfenix Formula Gold 650W PSU Review

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Teardown & Component Analysis

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General Data
Manufacturer (OEM)CWT
Platform ModelNo info
Primary Side
Transient Filter4x Y caps, 2x X caps, 2x CM chokes, 1x MOV, 1x CAP004DG
Inrush ProtectionNTC Thermistor & Relay
Bridge Rectifier(s)1x GBU1006 (800V, 10A @ 100°C)
APFC MOSFETs2x Champion GP28S50G (500V, 28A @ 150°C, 0.125Ω)
APFC Boost Diode1x STTH8S06D (600V, 8A @ 175°C)
Hold-up Cap(s)1x Nichicon (400V, 680uF, 105°C, GG series, 2000h @ 105°C)
Main Switchers2x Champion CMS6020
APFC ControllerChampion CM6502S & CM03X Green PFC controller
LLC Resonant ControllerChampion CM6901
TopologyPrimary side: Half-Bridge & LLC Resonant Converter Secondary side: Synchronous Rectification & DC-DC converters
Secondary Side
+12V MOSFETs4x International Rectifier IRFH7004TRPBF (40V, 164A @ 100°C, 1.4Ω)
5V & 3.3VDC-DC Converters: 2x UBIQ QM3006D FETs (30V, 57A @ 100°C, 5.5Ω) 2x UBIQ QM3016D FETs (30 V, 68 A @ 100°C, 4Ω) PWM Controller: Anpec APW7159C
Filtering CapacitorsElectrolytics: Chemi-Con (105°C, KY seriesKZE series) Polymers: FPCAP (Japan)
Supervisor ICSytronix ST9S429-PG14 (OCP [2x 12V channels, OVP, UVP, PG), Weltrend WD7518D (OCP [2x 12V channels], SCP) & UTC LM393G
Fan ModelMartech DF1202512SEMN (120mm, 12V, 0.37A, 2000 RPM, Rifle Bearing)
5VSB Circuit
Standby PWM ControllerTinySwitch-LT TNY177PN (18W Peak)

This platform shares a number of similarities with CWT's GPS. However, BitFenix's PSU PM let us know that it is a different and slightly modified version without any modular cables. We find a half-bridge topology and an LLC resonant converter on the primary side. On the secondary side, there's a synchronous rectification scheme for generating the +12V rail. The minor rails are handled by a couple of VRMs. The platform's PCB is underpopulated, so it doesn't reveal the PSU's true capacity. As usual for a CWT design, heat sinks on the secondary side are tiny. The +12V FETs are installed right below them, on the main PCB's solder side, and strangely enough they aren't cooled by the chassis.

BitFenix's build quality is very good. The company chose a reliable mix of electrolytic and polymer caps that should provide the desired reliability. It is always nice to see an increased number of polymer caps used for filtering purposes, since they're more tolerant of high operating temperatures than electrolytic capacitors.

Again, the cooling fan uses a rifle bearing, which is an improved version of the sleeve bearing. It offers a longer lifetime, since it uses gaskets to keep lubricant within the bearing. However, rifle bearing fans cannot match the lifetime of pricier FDB fans.

The following video footage shows the BF650G's internals.

We also have some photos of the fan's rifle bearing:

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Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

  • Dark Lord of Tech
    Great Review..Thanks!
  • turkey3_scratch
    Man this one is great! Thanks for the review, I appreciate the hard work you put into them.
  • Lutfij
    Was a great read for the weekend and an interesting one too. Keep up the good work Aris! ;)