A Look Inside And Component Analysis
Before proceeding, we strongly encourage you to review our PSU 101 article, which includes valuable information about PSUs and their operation, allowing you to better understand the information provided below.
Our main tools for disassembling PSUs are a Thermaltronics soldering and rework station and a Hakko 808 desoldering gun.
|Transient Filter||4x Y caps, 3x X caps, 2x CM chokes, 1x MOV|
|Inrush Protection||NTC Thermistor and relay|
|Bridge Rectifier(s)||1x Lite-On GBU1006 (600V, 10A @ 100 °C)|
|APFC MOSFETs||2x MagnaChip MMF60R190PTH (650V, 12.7A @ 100 °C, 0.19 ohm )|
|APFC Boost Diode||1x STTH12R06D (600V, 12A @ 175 °C)|
|Hold-Up Cap||1x Panasonic (450V, 560uF, 105 °C)|
|Main Switchers||4x Infineon IPP50R280CE (650V, 12.8A @ 100 °C, 0.19 ohm)|
|APFC Controller||Champion CM6502 - CM03X|
|Switching Controller||Champion CM6901|
|Topology||Primary side: Full bridge and LLC resonant converter Secondary side: Synchronous rectification & DC-DC converters|
|+12V MOSFETs||4x Infineon IPP023N04N G (40V, 100A @ 90 °C, 2.3 mohm)|
|5V & 3.3V||DC-DC Converters: 2x BSC050NE2LS FETs PWM Controller: 2x APW7073|
|Filtering Capacitors||Electrolytics: Nippon Chemi-Con (105 °C, KY, KZE) United Chemi-Con (105 °C, LXZ) Suncon (105 °C) Rubycon (105 °C) Polymers: Unicon (TW)|
|Supervisor IC||SITI PS223 (OVP, UVP, OCP, SCP, OTP )|
|Fan Model||Silencio A12025-25RB-2IN-F1 (120mm, 12V, 0.16A, 2250 RPM, Loop Dynamic Bearing)|
|Standby PWM Controller||STR-A6069H|
As mentioned, this PSU is made by Enhance Electronics, the same company responsible for the first VSM units. Cooler Master's V750 actually uses the same platform as the VSM750, with slight changes in various parts and the addition of a "3D" circuit required by the modular cabling design. This is a vertical PCB soldered directly onto the main board, which transfers the +12V rail to the modular sockets. Energy losses are consequently lower than if cables were used for this purpose. On top of that, internal airflow is improved.
A quick glance might not suggest that this is a 750W PSU; it's just so small. The main transformer is diminutive, and as you can see in the photos, it's only a little larger than the resonant tank. The DC-DC converters that generate the minor rails are also quite small. Thanks to those compact components, the PCA doesn't appear as crowded as you might expect.
The EMI filter starts at the AC receptacle, as usual, and includes two X and a pair of Y caps. It continues on the main PCA with one X and two Y caps, two CM chokes and an MOV. We also found an NTC thermistor that protects against large inrush currents, accompanied by an electromagnetic relay to bypass it once the start-up phase finishes. On the solder side of the PCB, we found a CM02X under the transient filter, which blocks the current through a X cap's discharge (bleeding) resistor once AC is connected.
The single bridge rectifier is bolted on the large APFC heat sink. It's most likely the same one used in the VSM750, a Lite-On GBU1006. We can't be certain, unfortunately, since the nearby X capacitor blocks our view. If the OEM indeed stuck with the GBU1006, then with lower VAC inputs (around 100V) and full load, the bridge rectifier will operate close to its limits.
Instead of the Infineon FETs that the VSM750 uses, we found two MagnaChip MMF60R190PTHs in the APFC converter. Enhance also uses a different boost diode, an STTH12R06D, instead of a CREE one. The bulk cap is by Panasonic (450V, 560uF, 105 °C) and has enough capacity to meet the PSU's requirements.
The PFC controller is a Champion CM6502 IC, supported by a CM03X Green PFC controller. Both are installed on a small daughterboard.
The main switches, four Infineon IPP50R280CEs, are arranged into a full bridge topology (among the best for high performance and low energy loss). There is also an LLC resonant converter that allows for even higher efficiency. The LLC and PWM resonant controller is a Champion CM6901, which is installed on the solder side of the main PCB. Right next to the CM6901 is the supervisor IC, a SITI PS223, armed with support for all basic protection features.
In the secondary side, four Infineon IPP023N04N Gs installed on a small heat sink rectify the +12V rail. Two thermistors are attached to the heat sink fins tasked with cooling down the +12V FETs. One provides temperature information to the fan control circuit and the other one is used by the over-temperature protection.
This PCB transfers the +12V rail to the modular sockets. It manages to accomplish this with minimal power loss, which makes a real difference in efficiency, especially at high loads.
The minor rails are regulated by two small DC-DC converters that are hosted on an equal number of vertical daughterboards. Each converter uses a couple of BSC050NE2LS FETs along with an Anpec APW7073 PWM controller.
The filtering caps on the main PCB are a mix of Nippon Chemi-Con, United Chemi-Con and Rubycon. All are rated at 105 °C, so they'll last, even under tough conditions. We also found several polymer caps, which most likely come from Unicon.
Several Suncon (Sanyo) electrolytic caps (along with two polymer ones) provide extra ripple filtering at the front side of the modular PCB.
The soldering quality is good; that's something we've come to expect from Enhance's implementations. We also noticed a couple of PCB traces that were touched up after production using copper wires. Finally, we also found a couple of Silicon Labs Si8233BD isolated drivers, along with a SG30N04D FET that feeds the 5VSB rail from the 5V one.
The fan uses a type of bearing that we have never encountered. It is called Looped Dynamic Bearing, and according to the schematics shared by Cooler Master, it looks to be an FDB (Fluid Dynamic Bearing) derivative. According to CM, this bearing has a lifetime that stretches up to 160,000 hours. Based on that fact alone, it'd be a serious upgrade over the VSM750's double ball-bearing fan with a <100,000 hour life. On top of that, the LDB is dust-proof.