X750 - Internal Design

Seasonic created a very unique layout with the X-Series. Even though the basic idea is similar to other designs (e.g. Revolution85+ series) in placing both VRMs on the PCB for cable management, it is an unusual structure together with SMDs (Surface Mounted Devices). The layout looks particularly open because all the rectifiers in the secondary circuit are on the back of the plate and only small dissipaters pass through the PCB.

We can see that the X-series wants to meet high-end requirements as opposed to the Pro/Modu87+ series by looking at the line filtering stage (from Yunpen) behind the AC-inlet, which is more expensive and improved compared to using individual filtering components. With a pair of Y-capacitors and a current-compensated choke it is suitable against common mode interferences, contains above all another X-capacitor. Also a MOV was integrated into the filtering, which continues on the motherboard together with some more devices.

Taking a look at the Power Factor pre-regulator, you can see a well stabilized choke and two Nippon Chemi-Con main capacitors. Both are specified at 400V, 360 microfarads, and 105 °C. The circuit with a resonance converter and champion controller (CM6901) follows, as already mentioned. The last component is physically located behind the fan control in the bottom left corner, as you can see on the following picture.

The X750 uses many solid-state capacitors, likewise from Nippon Chemi-Con, and small upright-coiled chokes shape the look of the secondary circuit. The PS223 safety device chip from Silicon Touch provides necessary safety features like OPP. There is still no OCP, but we have never encountered any problems in practice. Current flows over a small number of cables to the DC-to-DC converter, which is equipped with an Anpec controller. The smaller +3.3V and +5V are generated there connect to the connection panel and modular cables, along with +12V.

X750 - Resonant Topology X750 - Voltage Regulation and Quality
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  • vol7ron - Tuesday, April 13, 2010 - link

    Nice Martin, I've been looking at upgrading my PSU (550W ultra) and I only like buying the modular connectors. $200 still seems kind of high, but almost in the reasonable range. I'd like it to be $150 :)

    Another thing I might be shopping around for is a new UPS, have you guys reviewed any of those recently?
  • HOOfan 1 - Wednesday, April 14, 2010 - link

    There is a 650W version. Selling for $160 at newegg now
  • jeffbui - Wednesday, April 14, 2010 - link

    $138 at ewiz/superbiiz for the 650w version. I couldn't be happier with it.
  • vol7ron - Wednesday, April 14, 2010 - link

    I like the plan for the future though, especially with power supplies since they last long.

    My guess was that the next upgrade would be 750W or higher, the real goal was to have an 800W PSU and UPS. My machine probably only currently uses 350W, but I like to have headroom, especially since I keep adding HDs and will probably take advantage of more PCI slots in the future.
  • Souka - Wednesday, April 14, 2010 - link

    HX650 or HX750 (both are modular)

    HX650 is $120 at NewEgg, I have it... quiet and works well. Reviews show it to be 80+ Silver. but Corsair chose to be Bronze as their own testing (under very hot conditions) didn't qualify for Silver... Kudos to Corsair.
  • Souka - Wednesday, April 14, 2010 - link

    Sorry..my bad. Corsair PSU is Silver...almost Gold.

    One important thing about the HX650 and HX750 PSU is that they're just shy of 90% effecient at a VERY wide range of loading.

    True, the Seasonic unit does do better at PEAK efficiency (if using 220v) by a few %, but if you're actually going to use a 750W PSU at any other load than this, the Corsair will save you $$ upfront and in the long run with lower power bills.

    My $.02
  • HOOfan 1 - Wednesday, April 14, 2010 - link

    HX650 is bronze...nothing more than bronze

    HX750 is silver and was originally awarded Gold by 80plus.
  • Franson - Wednesday, April 14, 2010 - link

    Are you a bot or something? Take your stupid Corsair fanboyism and shove it....!!
  • Souka - Thursday, April 15, 2010 - link

    Wow... nice post...
  • piroroadkill - Thursday, April 15, 2010 - link

    The HX650 IS a Seasonic design, and I think, by looking at it, the HX750 is a Channel Well design. Regardless, Seasonic was also the OEM for the HX520 and HX620. Seasonic make damn fine power supplies.

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