When it comes to Gujia, I believe many players who have just entered the PC DIY field may be unfamiliar, but for old players who have been immersed in the industry for many years, they are quite familiar because Gujia is actually one of the top players in the PC electromechanical field. However, in recent years, it has been relatively low-key and has not made strong promotions, which makes it slightly unfamiliar to new players. However, Gujia is not planning to keep a low profile all the time. Recently, their power products have made a strong debut, and the GEX series power supplies can be said to be coming with great momentum.
The Gujia GEX series power supply plan has four products, namely 550W, 650W, 750W, and 850W styles, while the two products currently entering the market are 650W and 750W. Both of these power supplies have passed the 80Plus Gold certification, providing good support for various platforms, and all offer a 5-year warranty service. The price of 699/799 yuan is also quite attractive, making it another new choice for mainstream and mid to high end platforms.
| Gujia GEX 750 power supply specifications | ||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Basic specifications | ||||||||||||||||||||||||||||||||||
| model | GEX750 | |||||||||||||||||||||||||||||||||
| Rated power | 750W | |||||||||||||||||||||||||||||||||
| structure | Active PFC+full bridge LLC resonance+synchronous rectification + DC-DC | |||||||||||||||||||||||||||||||||
| AC input | 100~240Vac / 10-5A / 50~60Hz | |||||||||||||||||||||||||||||||||
| Efficiency certification | 80Plus金牌 | |||||||||||||||||||||||||||||||||
| size | 160 * 150 * 86 mm | |||||||||||||||||||||||||||||||||
| Net weight | 1.51 Kg | |||||||||||||||||||||||||||||||||
| Fan | 120mm Hydraulic bearing fan | |||||||||||||||||||||||||||||||||
| Warranty | 5year | |||||||||||||||||||||||||||||||||
| price | 799￥ | |||||||||||||||||||||||||||||||||
| DC output | ||||||||||||||||||||||||||||||||||
| Voltage | +3.3V | +5V | +12V | -12V | +5Vsb | |||||||||||||||||||||||||||||
| Maximum current | 18A | 20A | 62.5A | 0.3A | 3A | |||||||||||||||||||||||||||||
| Joint output | 100W | 750W | 3.6W | 15W | ||||||||||||||||||||||||||||||
| Rated power | 750W | |||||||||||||||||||||||||||||||||
| Number of interfaces | ||||||||||||||||||||||||||||||||||
| 24pin Main power supply | 1 | |||||||||||||||||||||||||||||||||
| 4+4pin CPU power supply | 1 | |||||||||||||||||||||||||||||||||
| 8pin CPU power supply | 1 | |||||||||||||||||||||||||||||||||
| 6+2pin PCI-E power supply | 4 | |||||||||||||||||||||||||||||||||
| SATA power supply | 8 | |||||||||||||||||||||||||||||||||
| D 4pin power supply | 6 | |||||||||||||||||||||||||||||||||
| 超 能 网 制 作 | ||||||||||||||||||||||||||||||||||
Gujia GEX 750 power supply
Gujia GEX 750 power supply
The Gujia GEX 750 belongs to the 16cm length ATX power supply, weighing around 1.5kg, with a black body. The fan grille and housing are designed as an integrated unit, and the Gujia logos on the left and right sides are directly stamped on steel plates instead of common stickers. These designs give the power supply a stronger sense of unity.
The power supply uses a 12cm diameter 9-blade fan for heat dissipation
The bone logo of stamping process has a more three-dimensional sense
The rated power of the Gujia GEX 750 power supply is 750W, using an active PFC+full bridge LLC resonance+synchronous rectification+DC to DC structure, supporting 100V to 240V AC input, single channel+12V output design, with a rated output current of 62.5A, equivalent to 750W power.+5V and+3.3V are converted from+12V through DC to DC, with rated currents of 18A and 20A respectively. The combined output power is rated 100W, and the+5V standby output is rated 3A current.
The AC input interface of the Gujia GEX 750 power supply has an independent switch
The Geely GEX 750 power supply adopts a full module interface design, with 3 sets of 8-pin interfaces and 4 sets of 6-pin interfaces. The 8-pin interface is used to expand the CPU power supply interface and PCI-E power supply interface, the 6-pin interface is used to expand the SATA power supply interface and D-type 4-pin power supply interface, and the 24 pin main power supply interface is expanded through a 10+18pin interface.
The module cables of the Gujia GEX 750 power configuration can be fully plugged into all interfaces, providing a total of 1 24 pin main power supply interface, 1 4+4-pin CPU power supply interface, 1 8-pin CPU power supply interface, and 4 6+2pin PCI-E power supply interfaces. There are 8 SATA power supply interfaces and 6 D-type 4-pin power supply interfaces, which can meet the usage needs of current mainstream or mid to high end platforms.
In terms of wiring, the 24 pin main power supply wire of the Geely GEX 750 power supply is designed as a braided mesh wire, while the other wires are black flat wires. The CPU power supply interface adopts a "one to two" design, which means that one module wire extends to two CPU power supply interfaces. This design is relatively simple in wiring, but in situations where the CPU power load is high, the module interface may bear greater pressure.
Gujia GEX 750 power supply packaging
The fan used in the Gujia GEX 750 power supply is our own product, model DF1202512RFMN, with specifications of DC12V 0.20A, 9-blade design, and HDB hydraulic dynamic bearings. It is worth mentioning that unlike most power supplies that install plastic sheets on the fan to strengthen the air duct, the fan of the Geely GEX 750 power supply is specially molded and customized, and the corresponding area is directly closed on the fan frame, indicating that they have put a lot of effort into this power supply.
The Gujia GEX 750 power supply adopts an active PFC+full bridge LLC resonant+synchronous rectification+DC to DC design. The PFC controller is ON Semiconductor's NCP1654, and the LLC resonant controller is CM6901T6X. Both controllers and the+12V synchronous rectification MosFET are placed on the back of the main PCB.
Back of the main PCB of the Gujia GEX 750 power supply
The LLC resonant controller uses CM6901T6X
Level 1 EMI of Gujia MWE 750 power supply
Secondary EMI of Gujia GEX 750 power supply
The Geely GEX 750 power supply has complete primary and secondary EMI circuits. The primary EMI configuration has an independent sub PCB with one X capacitor, one pair of Y capacitors, and a fuse tube. The secondary EMI configuration has two X capacitors, one pair of Y capacitors, and two common mode inductors. The MOV and NTC are complete, and the NTC configuration has an independent relay placed next to the switch tube and main capacitor on the primary side.
The main capacitor of the power supply comes from daily chemical products, with a specification of 400V/560 μ F/105 ℃
The rectifier bridge, primary side, and main switch tube of the Gujia GEX 750 power supply are each equipped with independent heat sinks. There is only one rectifier bridge, but the specific model cannot be observed due to the presence of curing adhesive on the surface; The PFC diode on the primary side is completely blocked by NTC, and the specific model cannot be observed; The PFC switch tube consists of 2 NCE65TF130 with a specification of 650V/ 18A@100 ℃/110mΩ。
The power supply adopts the full bridge LLC resonance scheme, equipped with 4 main switch tubes and shared heat sinks. The model is GPT10N50ADG, with a specification of 500V/9.7A/0.7 Ω.
Gujia GEX 750 Power Supply Main Transformer
The+5V standby mode of the Gujia GEX 750 power supply uses EM8569C
Gujia GEX 750 power supply+12V output uses solid-state capacitors for filtering
The+12V output of the power supply adopts synchronous rectification design. The heat sink and solid-state capacitor for filtering are arranged on the front of the PCB, while the rectifier and freewheeling tubes are on the back of the PCB. It is equipped with 4 P16N04S with a specification of 40V/ 100A@100 ℃/1.6m Ω, 2 rectifier tubes and 2 freewheeling tubes.
The+5V and+3.3V of the Geely GEX 750 power supply are designed with DC to DC, equipped with independent sub PCBs, and use conventional open inductors and solid-state capacitors for filtering. Its PWM controller is uP3861P, equipped with one rectifier MosFET and one freewheeling MosFET per channel, both of which are EMB06N03HR, with a specification of 30V/ 45A@100 ℃/6m Ω.
Gujia GEX 750 power output terminal
Multiple 2200 μ F capacitors are used for output filtering
Gujia GEX 750 power module interface PCB uses solid-state capacitors for filtering
At present, we will conduct a 230V input balanced load test and ripple test on all tested power supplies at 120% rated power. The results of this test will not be included in the calculation of the superpower index and will only be used to observe the power margin of the power supply.
Gujia GEX 750 Power Balance Load Test
| output power(W) | 12V Voltage(V) | 5V Voltage(V) | 3.3V Voltage(V) | -12V Voltage(V) | 5VSB Voltage(V) | 115V efficiency(%) | PF value | 230V efficiency(%) | |||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 30 | 12.068 | 5.030 | 3.338 | -11.587 | 5.114 | 73.37 | 0.598 | 74.54 | |||||||||||||||||||||||||||||
| 50 | 12.068 | 5.030 | 3.338 | -11.612 | 5.111 | 80.70 | 0.716 | 81.69 | |||||||||||||||||||||||||||||
| 75 | 12.068 | 5.030 | 3.338 | -11.643 | 5.107 | 85.28 | 0.800 | 86.47 | |||||||||||||||||||||||||||||
| 100 | 12.068 | 5.030 | 3.338 | -11.675 | 5.106 | 88.23 | 0.844 | 89.27 | |||||||||||||||||||||||||||||
| 150 | 12.062 | 5.031 | 3.338 | -11.725 | 5.101 | 90.75 | 0.904 | 91.43 | |||||||||||||||||||||||||||||
| 200 | 12.068 | 5.031 | 3.338 | -11.787 | 5.095 | 91.49 | 0.933 | 92.25 | |||||||||||||||||||||||||||||
| 250 | 12.068 | 5.031 | 3.338 | -11.831 | 5.089 | 91.54 | 0.946 | 92.71 | |||||||||||||||||||||||||||||
| 300 | 12.068 | 5.031 | 3.338 | -11.875 | 5.083 | 91.37 | 0.957 | 93.00 | |||||||||||||||||||||||||||||
| 350 | 12.062 | 5.031 | 3.338 | -11.918 | 5.077 | 91.25 | 0.964 | 93.16 | |||||||||||||||||||||||||||||
| 375 | 12.062 | 5.031 | 3.338 | -11.943 | 5.075 | 91.25 | 0.968 | 92.97 | |||||||||||||||||||||||||||||
| 400 | 12.062 | 5.032 | 3.338 | -11.968 | 5.071 | 90.67 | 0.972 | 92.65 | |||||||||||||||||||||||||||||
| 450 | 12.062 | 5.032 | 3.338 | -12.025 | 5.066 | 90.39 | 0.974 | 92.93 | |||||||||||||||||||||||||||||
| 500 | 12.056 | 5.033 | 3.338 | -12.075 | 5.060 | 90.10 | 0.982 | 92.34 | |||||||||||||||||||||||||||||
| 550 | 12.056 | 5.033 | 3.338 | -12.125 | 5.055 | 89.72 | 0.983 | 92.36 | |||||||||||||||||||||||||||||
| 600 | 12.056 | 5.034 | 3.339 | -12.175 | 5.051 | 89.30 | 0.985 | 92.11 | |||||||||||||||||||||||||||||
| 650 | 12.056 | 5.035 | 3.340 | -12.206 | 5.046 | 88.89 | 0.987 | 92.02 | |||||||||||||||||||||||||||||
| 700 | 12.056 | 5.035 | 3.340 | -12.250 | 5.041 | 88.62 | 0.988 | 91.57 | |||||||||||||||||||||||||||||
| 750 | 12.056 | 5.036 | 3.340 | -12.306 | 5.036 | 88.08 | 0.987 | 91.34 | |||||||||||||||||||||||||||||
| 800 | 12.050 | 5.036 | 3.341 | -12.368 | 5.032 | - | 0.988 | 91.13 | |||||||||||||||||||||||||||||
| 850 | 12.050 | 5.037 | 3.341 | -12.431 | 5.027 | - | 0.989 | 90.64 | |||||||||||||||||||||||||||||
| 900 | 12.050 | 5.038 | 3.342 | -12.493 | 5.023 | - | 0.989 | 90.44 | |||||||||||||||||||||||||||||
| Maximum voltage deviation(%) | 0.57 | 0.72 | 1.21 | 3.44 | 2.28 | - | 平均效率 | 91.49 | |||||||||||||||||||||||||||||
| Load adjustment rate(%) | 0.10 | 0.12 | 0.06 | -5.99 | 1.56 | - | - | - | |||||||||||||||||||||||||||||
| 超 能 网 制 作 | |||||||||||||||||||||||||||||||||||||
After overloading to 120% power, the output voltage of the Gujia GEX 750 power supply remains at a normal level, and the change in conversion efficiency is also within the normal range, indicating that its power margin is very sufficient.
PS：Overloading to 120% power is a requirement for eva1uation, and we do not recommend players to overload the power supply. If higher output power is indeed needed, please use products with higher rated power.
conversion efficiency
The Gujia GEX 750 power supply is a power supply that has passed the 80Plus Gold certification. When the power output reaches 50W, its conversion efficiency under 115V and 230V inputs exceeds 80%; In a 230V input environment, the conversion efficiency exceeds 88% when outputting 100W, the half load output efficiency exceeds 92%, and the highest exceeds 93%. The overall average efficiency is 91.5%; At 115V input, the highest conversion efficiency exceeds 91%, and the full load efficiency is over 88%, truly reaching the level of the 80Plus gold medal.
Standby efficiency
According to relevant specifications and standards, the+5V standby conversion efficiency of the power supply should be higher than 50%, 60%, and 70% under a load of 0.1A/0.25A/1A, and the no-load power should be less than 1W. The idle standby input of the Gujia GEX 750 power supply is 0.23W, and the+5V standby output voltage is sufficient, with good conversion efficiency.
Cooling fan speed
The Gujia GEX 750 power supply supports automatic shutdown of low load and low-temperature fans. This design ensures that the power supply is quiet enough during low temperature and low load, while also ensuring sufficient heat dissipation efficiency under high load. According to our testing, the fan of the power supply stops running before reaching half load, and then increases its speed with the increase of power output. The starting speed is 750 RPM, and the full load speed reaches 1500 RPM. The noise level remains very low, and the user experience is very good.
voltage stability
The output voltage performance of the Gujia GEX 750 power supply is excellent, with a maximum deviation of less than 1% between the+12V and+5V output voltages, and a maximum deviation of no more than 1.5% for the+3.3V output voltage. The voltage regulation rate can be controlled within 0.5%, and the stability is among the best in ATX power supplies.
Output ripple
Ripple and noise are AC components mixed in the DC output of a power supply. If observed with an oscilloscope, slight fluctuations in voltage can be seen, resembling water ripples, hence it is called ripple. According to Intel ATX12V 2.52 regulations, the Vp-p (peak to peak) of output ripple and noise for+12V,+5V, and+3.3V must not exceed 120mV, 50mV, and 50mV, respectively. We use a digital oscilloscope to measure the output ripple of the power supply at full load and overload to 120% power by connecting decoupling capacitors to the measurement points of the fixture board according to Intel specifications under a 20MHz analog bandwidth. The peak to peak value of the ripple at low frequencies is used as the scoring benchmark.
The low-frequency ripple of+12V,+5V, and+3.3V of the power supply at 100% full load is 42mV, 19mV, and 18mV. After overloading to 120%, which is 900W, the output ripple of the power supply increases slightly, rising to 48mV, 24mV, and 21mV respectively, still at the same performance level, indicating that its ripple suppression level is relatively excellent.
Cross load
We have developed a 750W power supply cross load chart for the cross load testing project in accordance with the requirements of the Intel ATX12V 2.52 and SSI EPS12V 2.92 power supply design guidelines.
It is worth noting that we did not simply copy the design specifications, but only selected four test points that are more practically meaningful, namely the bottom left, top left, top right, and bottom right corners of the cross load box.
The meanings of these four points are:
Bottom left corner (point A): Minimum load of the whole machine;
Top left corner (point B): Maximum load of auxiliary circuit, minimum load of 12V, such as when multiple mechanical hard drives are started simultaneously;
Upper right corner (point C): maximum load on auxiliary road, full load of the whole machine;
Bottom right corner (point D): Maximum load of 12V, minimum load of auxiliary circuit, such as when running 3D games with a single solid-state drive;
The X coordinate of the test point represents the total output power of+12V, and the Y coordinate represents the sum of the output power of+5V and+3.3V.
The eva1uation criteria for cross load testing are consistent with those for uniform load testing. The less voltage deviation from the rated value, the better. The allowable deviation rate for each circuit is ± 5%.
The Gujia V750 SFX Gold power supply adopts a DC to DC design on the+5V and+3.3V outputs, which is advantageous in cross load (pull bias test). Moreover, in different load environments, the voltage deviation trend of the three outputs is the same, and the variation amplitude is also very small, which can be regarded as excellent performance.
Maintain time
The Hold up Time refers to the time during which the voltage output value drops out of the allowable range by 5% after a power failure. We measure the holding time of+12V,+5V, and Power OK signals.
The requirement for the output voltage holding time in the SSI EPS12V 2.92 server power supply design guide is that the holding time of the power supply should be greater than 18ms at 75% load, while the holding time requirement for the Power OK signal is greater than 17ms.
The reason why the power outage duration is so concerned is because it is largely related to the lifespan of hardware. A Power OK duration of 17ms means that the computer can continue to operate without shutting down or restarting in the event of a power outage within 17ms. The duration of 18ms or longer for various voltages is to enable emergency response by various hardware in the event of a power outage, such as the head reset of mechanical hard drives and the power outage protection of SSDs.
The holding time of the Geely GEX 750 power supply was measured at 75% load (DC output 562.5W).
For+12V and+5V, the qualified standard is that the holding time should be equal to or greater than 18ms, and the Power OK (or PG, Power Good) time should be equal to or greater than 17ms. The+12V holding time of the Geely GEX 750 power supply is 32.8ms,+5V is 42.4ms, and Power OK is 21.2ms. All three holding times meet the standards and the margin is very sufficient.
According to our current rating criteria, the Geely GEX 750 power supply has a superpower index of 92.67 points, which has entered the category of top power supplies and is worth choosing for players who pursue power performance.
Although Gujia has rarely made strong promotions in the DIY PC field in recent years, its strength in PC power products cannot be underestimated. The performance of the GEX 750 power supply is enough to illustrate everything. This power supply has excellent performance in voltage stability, conversion efficiency, output ripple, and holding time, among other aspects. Especially, the voltage stability is almost impeccable, making it a reliable choice for players who pursue power performance.
Of course, there is still room for improvement in the Gujia GEX 750 power supply. Firstly, its module interface PCB is connected to the main PCB through wires, rather than using a direct insertion design. This solution is generally designed to be shared with the native wire version, but the extra wires will occupy the internal space of the power supply, which is not conducive to reducing its size; In addition, the CPU interface module cable for the power configuration adopts a "one to two" design, with all two interfaces placed on one wire. Although wiring may be relatively simple, if the CPU power supply demand is high, it may lead to excessive load pressure on the wire terminals and a higher risk of damage. However, the Gujia team has confirmed that they will make improvements in this aspect in future products, and we are also looking forward to it.
At present, the official selling price of the Geely GEX 750 power supply is 799 yuan, which comes with a 5-year warranty service. This price is in line with its performance and is quite competitive in the market, suitable for players using mid to high end platforms.