Page 3 - Physical Look - Inside
As always, we opened up our Deepcool Quanta DQ750 750W power supply to take a detailed look at what is going on inside. Please note that doing this at home will void your 3-year warranty, thanks to the warranty seal Deepcool applied over one of the attachment screws. But for the benefit of you, we cracked ours open so you do not need to, haha. There are no user serviceable parts inside.
Disassembling the Deepcool Quanta DQ750 750W was quite straightforward, with the removal of six screws. Two were located at the top, with four on the sides. The Quanta DQ750 750W's OEM is Channel Well Technology (CWT), a reputable OEM since 1993. It was the OEM to PSUs like the Thermaltake Toughpower XT Platinum 1275W and Thermaltake SMART M750W. Our photo above shows an overhead view of its internal components. At first glance, the build quality appears to be excellent, as one would expect from the company. There are only three heatsinks inside the DQ750; all of which are painted black, and are compact in size.
A quick tug on the shell, and we got straight to the internal inspection. The transient filter stage is the first input stage of a computer power supply, so we will take a look at that first. I have never reviewed a Deepcool PSU before, so I cannot comment on whether or not they have always ensured their power supplies met or exceeded the recommended requirements. However, CWT is a reputable OEM as aforementioned. The Deepcool Quanta DQ750 750W has two ferrite coils, one metal oxide varistor, four metalized polyester X-capacitors, and four ceramic Y-capacitors. This is twice the amount of X capacitors and twice the amount Y capacitors than recommended. Considering how many modern day PSUs have missing MOVs, I am happy to see it here, as this component is used to stabilize spikes from the AC line.
On the primary side, we can see one Chinese made CapXon capacitor. Japanese made capacitors are usually what we expect from something in this price range, so we were quite surprised by the company's selection. Our 750W version of Deepcool's Quanta series incorporates one 390µF x 400V capacitor. These units are rated at 85c, which is a second surprise to us today, considering virtually all power supplies in this class and price range have 105c rated capacitors.
The active PFC circuit featured on the Deepcool Quanta DQ750 750W uses two Lite-On Semiconductor GBU606 glass passivated bridge rectifiers. A Champion CM6802 no bleed resistor green mode PFC/PWM controller combo can be spotted in close proximity. At 115V, the maximum rectified forward current capacity with heatsink is 6A each, so you can theoretically pull up to 1380W (6A * 2 diodes * 115V) from the bridge rectifier at 100% efficiency -- of course, this is limited by the fact that it is not 100% efficient, and also neglects the fact that not every component in the system are able to keep up. Two Vishay Siliconix SiHG20N50C power MOFSET transistors are used on the active PFC circuit on the Deepcool Quanta DQ750 power supply, with a power diode off to the side. Two Infineon IPP60R125CP power transistors can also be found on the middle aluminum heatsink, plus a STMicroelectronics STF3NK80Z for the standby output. Each Vishay Siliconix SiHG20N50C MOFSET can deliver up to 11A at 100 degrees Celsius continuously. These transistors present a maximum resistance of 0.270 ohm when turned on; with a typical resistance of 0.225 ohm according to the manufacturer's data sheet. The Infineon IPP60R125CP can deliver up to 16A at 100 degrees Celsius continuously; with a maximum resistance of 0.125 ohm, and a typical resistance of 0.110 ohm. 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 secondary side, we can see more CapXon capacitors rated at 105c. There is a lone Nippon Chemi-Con for the +5VSB stage. As with modern high efficiency power supplies, all rectifiers produces 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. The +12V output is produced by four Infineon IPD031N06L3 power transistors. The IPD031N06L3's rated continuous drain current is 100A at 100c, and a pulsed drain current of 400A. Drain source voltage is rated at 20V, and a RDS(on) value of only 0.0031 ohm.
At the back, we have a large daughterboard covering the entire rear panel for the modular cable sockets. Here, we can see parts of the DC to DC converter, where we have an ANPEC APW7159 synchronous buck PWM controller for each rail. Four Advanced Power Electronics AP72T03GH MOSFETs are responsible for the minor rail generation. The AP72T03GH's rated continuous drain current is 44A at 100c, and a pulsed drain current of 190A. Drain source voltage is rated at 30V, and a RDS(on) value of only 0.008 ohm. This is completed in conjunction with the minor rail generation done by voltage regulator modules on the modular PCB to further improve efficiency. The datasheets for all components mentioned in this review can be found on their respective manufacturer's websites.
All sockets are connected to the main circuit board after the secondary stage by a bundle of wires. The output connector configuration can be seen on the previous page. Overall, the internal build quality of Deepcool's Quanta DQ750 750W power supply is acceptable at best. I would definitely expect better build quality for something of this price range. Components are arranged pretty well for optimal cooling with minimal wires running around inside, but the quality of solder points on its black PCB leaves a bit to be desired. I would say the Deepcool branded, Channel Well Technology built DQ750 has quite a bit of room for improvement with regards to the selection of components used under the hood.
Lastly, we see a 140mm fan that provides cooling to the Deepcool Quanta DQ750 750W's internal components. It is connected to the mainboard using a 2-pin connector. A 120mm fan is rather small nowadays for a power supply with a bottom mounted fan, but if not a lot of heat is being generated, it should not be much of an issue. A 140mm fan is probably the largest one you can fit inside a standard ATX power supply, and it is beneficial in most cases in providing lots of airflow at lower speeds for quiet operation. Yate Loon is the fan OEM, with D14SH-12 as the model number, as shown in our photo above. This is basically the larger, blue LED variant of the D12SH-12 used in the SilverStone Strider Essential Gold ST70F-ESG 700W. Further research indicates the D14SH-12 is a hybrid ceramic ball bearing fan specified at 0.70A for a maximum of speed of 2800 rpm. The rated airflow is 140 CFM at 48.5 dB of noise.
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion