Page 3 - Physical Look - Inside
As always, we opened up the GAMDIAS HELIOS P2-750G 750W power supply to take a detailed look at what is going on inside. Please note that doing this at home will void your warranty, thanks to the seal applied over the connecting edges between the two halves. For your benefit, we opened ours up, so you do not need to. There are no user serviceable parts inside.
Opening the GAMDIAS HELIOS P2-750G 750W is quite straightforward with the removal of four screws. Taking out the internal components from the enclosure requires the removal of even more screws, but most of the important parts can be found from this side. The OEM for this power supply is High Power, formerly known as Sirfa or Sirtec. It features an LLC half-bridge topology with DC-to-DC converters. This is in contrary to what their website claims at press time of being a full-bridge design. At first glance, the build quality appears to be average. There are four heatsinks inside, located on both the primary and secondary side. The two heatsinks on the secondary side do not seem to have any components directly attached to it on the top, but there are components underneath that use this.
Starting with the transient filter stage, there is a total of two X-capacitors and four Y-capacitors near or around the input. This is twice the minimum amount of X and Y capacitors recommended. In addition, we have two common mode chokes and a metal oxide varistor. The MOV helps with suppressing voltage spikes. Considering some modern-day PSUs are missing MOVs, I am happy to see it here.
The active PFC circuit featured on the GAMDIAS HELIOS P2-750G 750W uses two Hy Electronic Corp bridge rectifiers on each side of a heatsink. Unfortunately, I was unable to get any more from the markings of the bridge rectifiers, as they were covered up either by a heatsink or by a large glob of glue. Further down the line, we can see two active PFC MOSFETs, which are Infineon IPA60R120P7 power transistors. Each one is certified for up to 16A at 100c. These transistors present a typical resistance of 100 mΩ and maximum resistance of 120 mΩ when turned on according to the manufacturer's data sheet. This on characteristic is called Static Drain-Source On-Resistance, or commonly abbreviated as RDS(on). The more efficient the component is, the lower the RDS(on) value, since it wastes less power with lower resistance. On the same heatsink, there is one Maplesemi MSP08065G1 Schottky diode to act as a boost diode.
The primary capacitor is a single Taiwanese Teapo LH 680µF x 420V. This is rated at 85c, which is rather unfortunate. Most power supplies we see nowadays use 105c, which indicates better durability and quality of the capacitors. Finally, we have two switcher MOSFETs located on the same heatsink near the active PFC MOSFETs. These are the same Infineon IPA60R120P7 we have mentioned previously. Clearly, this is a half-bridge topology and not the full bridge topology as GAMDIAS claims on their website.
Other components on the primary side can be found here too. First, we have a Champion CM6901X switching controller on an add-in board. Another MOSFET can be found on its own and attached to the main PCB. This is marked as a Huajing Micro 4N65FA9K. Finally, another add-in board holds an Infineon ICE3PCS01G, which is the active PFC controller.
On the secondary side, we can see even more Taiwanese-made electrolytic capacitors from Teapo, but these are rated at 105c. There are also polymer capacitors that appear to be made by Jamicon, which is another name for Teapo. There are also a couple of daughterboards that hold other components.
All rectifiers produce the +12V out, while the +5V and +3.3V outputs are generated from the +12V output using a DC-to-DC converter within the power supply unit. A total of six Infineon BSC027N04LS MOSFETs generate the +12V output. These are located on the other side of the printed circuit board, with a large thermal pad making contact with the exterior shell. Its rated continuous drain current is 139A at 25c. It has an RDS(on) value of 2.7mΩ maximum and 2.3mΩ typical at 10V.
On a different add-in board, we have the MOSFETs that generate the +5V and +3.3V output from the +12V rail. I could not exactly tell if there were three or four, as part of the add-in board was obscured from my vision by the fixed cables, but they all appeared to be Vishay Siliconix SiRA12BDP MOSFETs. These act as the DC-to-DC converter. The SiRA12BDP has a drain to source current of 74A at 25c and 59A at 70c, with an RDS(on) of 4.3mΩ and a typical resistance of 2.7mΩ at 10V. Finally, an uPI Group uP3861P can be found on the same daughterboard and is used for controlling the PWM switching.
Other components on other add-in boards include a Weltrend WT7527RA monitoring IC, which provides overvoltage, undervoltage, and overcurrent protection, as well as the power good signal. Another KEC KIA7912PI voltage regulator is also found near the output. The datasheets for all of the components mentioned in the inspection should be found on their respective manufacturer's website.
Finally, you can see where all the cables are connected and sleeved to lead outside of the GAMDIAS HELIOS P2-750G 750W. There is nothing too special here, other than the fact there are a lot of cables running around. The overall build quality is average for a budget power supply with some corners cut to keep the costs down. Component selection is on the lower tier of parts generally. Some parts are pretty close together, but the large heatsinks and relatively open layout should help with heat dissipation.
As for cooling, a single 120mm Poweryear PY-1225M12S fan is connected to the mainboard of the power supply. This is a sleeve bearing fan, which is common for budget-oriented power supplies. From the label, you can see this fan operates at 12V and 0.26A. As we mentioned previously, there is no zero RPM fan mode with this power supply, so this fan will always spin when the unit is turned on. Once again, this is in contrary to their product page at press time, which claims the HELIOS P2-750G features a hydraulic bearing fan with silent mode operation.
Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion
