Introduction

The LEPA already had a power supply series called “G,” with 500 W, 700 W, and 900 W models. We reviewed the 500 W and 700 W models, and they deserved our recommendation. Now LEPA is releasing 650 W, 750 W, and 850 W models within its “G” series, but those models are manufactured by a different company. Let’s see how the new 850 W model fared in our tests.

The new 650 W, 750 W, and 850 W models are manufactured by CWT, while the 500 W, 700 W, and 900 W models are manufactured by Enermax. The LEPA G850-MAS is a rebranded CWT PUQ(G)-850 (a.k.a. PUQ750V-G) power supply.

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Figure 1: LEPA G850-MAS power supply

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Figure 2: LEPA G850-MAS power supply

The LEPA G850-MAS is 6.3” (160 mm) deep, using a 140 mm ball-bearing fan on its bottom (Yate Loon D14BH-12).

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Figure 3: Fan

The reviewed power supply has a modular cabling system with six connectors: two for video cards and four for SATA or peripheral power connectors. The main motherboard cable and the ATX12V/EPS12V cables are permanently attached to the power supply. These cables are protected with nylon sleeves, which come from inside the unit. This power supply comes with the following cables:

• Main motherboard cable with a 24-pin connector, 22.4” (57 cm) long, permanently attached to the power supply
• One cable with two ATX12V connectors that together form an EPS12V connector, 23.6” (60 cm) long, permanently attached to the power supply
• One cable with one EPS12V connector, 23.6” (60 cm) long, permanently attached to the power supply
• Two cables, each with two six/eight-pin connectors for video cards, 18.1” (46 cm) to the first connector, 5.9” (15 cm) between connectors, modular cabling system
• Three cables, each with four SATA power connectors, 18.1” (46 cm) to the first connector, 5.9” (15 cm) between connectors, modular cabling system
• One cable with four standard peripheral power connectors and one floppy disk drive power connector, 18.1” (46 cm) to the first connector, 5.9” (15 cm) between connectors, modular cabling system

All wires are 18 AWG, which is the minimum recommended gauge, except the main motherboard cable, which uses thicker 16 AWG wires. The number of connectors is adequate for an 850 W power supply, however, we’d prefer that this power supply would come with six video card power connectors, which would allow for out-of-the-box support for three high-end video cards.

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Figure 4: Cables

Let’s now take an in-depth look inside this power supply.

A Look Inside the LEPA G850-MAS

We decided to disassemble this power supply to see what it looks like inside, how it is designed, and what components are used. Please read our “Anatomy of Switching Power Supplies” tutorial to understand how a power supply works and to compare this power supply to others.

On this page we will have an overall look, and then in the following pages we will discuss in detail the quality and ratings of the components used.

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Figure 5: Top view

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Figure 6: Front quarter view

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Figure 7: Rear quarter view

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Figure 8: The printed circuit board

Transient Filtering Stage

As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil. 

In the transient filtering stage, this power supply is flawless, with two Y capacitors and one X capacitor more than the minimum required.

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Figure 9: Transient filtering stage (part 1)

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Figure 10: Transient filtering stage (part 2)

On the next page, we will have a more detailed discussion about the components used in the LEPA G850-MAS.

Primary Analysis

On this page we will take an in-depth look at the primary stage of the LEPA G850-MAS. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses two GBU806 rectifying bridges connected in parallel and attached to an individual heatsink. Each bridge supports up to 8 A at 100° C. So, in theory, you would be able to pull up to 1,840 W from a 115 V power grid. Assuming 80% efficiency, these bridges would allow this unit to deliver up to 1,472 W without burning themselves out (up to 1,656 W at 90% efficiency). Of course, we are only talking about these particular components. The real limit will depend on all the components combined in this power supply.

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Figure 11: Rectifying bridges

The active PFC circuit uses two IPW60R190E6 MOSFETs, each supporting up to 20.2 A at 25° C or 12.8 A at 100° C in continuous mode (see the difference temperature makes) or 59 A at 25° C in pulse mode. These transistors present a maximum 190 mΩ resistance when turned on, a characteristic called RDS(on). The lower the number the better, meaning that the transistor will waste less power, and the power supply will have a higher efficiency.

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Figure 12: Active PFC transistors

The output of the active PFC circuit is filtered by one 470 µF x 400 V Japanese electrolytic capacitor, from Panasonic, labeled at 105° C.

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Figure 13: Capacitor

In the switching section, two IPW60R099C6 MOSFETs are employed using the traditional two-transistor forward configuration. Each transistor supports up to 37.9 A at 25° C or 24 A at 100° C in continuous mode or 112 A at 25° C in pulse mode, with a maximum RDS(on) of 99 mΩ.

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Figure 14: Switching transistors

The switching transistors are managed by a CM6802 active PFC/PWM combo controller.

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Figure 15: Active PFC/PWM controller

Let’s now take a look at the secondary of this power supply.

Secondary Analysis

The LEPA G850-MAS uses a synchronous design, meaning that the rectifiers were replaced with MOSFETs. Also, this power supply uses a DC-DC design, meaning that it is basically a +12 V power supply, with the +5 V and +3.3 V outputs being generated through two smaller switching power supplies connected to the +12 V rail. Both designs are used to increase efficiency.

The +12 V output uses five IPD031N06L3 G MOSFETs, each supporting up to 100 A at 100° C in continuous mode or up to 400 A at 25° C in pulse mode, with a maximum RDS(on) of 3.1 mΩ. These transistors are controlled by an SP6019 integrated circuit, and they are located on a small daughterboard.

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Figure 16: The +12 V transistors

The DC-DC converters are located on the same printed circuit board as the modular cabling system. Both are managed by an APW7159 PWM controller, with each output using a pair of AP72T03GH MOSFETs, each supporting up to 63 A at 25° C or 44 A at 100° C in continuous mode or up to 190 A at 25° C in pulse mode, with a maximum RDS(on) of 9 mΩ.

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Figure 17: The DC-DC converters

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Figure 18: The DC-DC converters

The outputs of this power supply are monitored by a WT7502 integrated circuit, which only supports over voltage (OVP) and under voltage (UVP) protections.

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Figure 19: Monitoring circuit

This power supply uses a mix of Japanese electrolytic capacitors, from Chemi-Con, and solid capacitors to filter its outputs. See Figure 20.

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Figure 20: Capacitors

Power Distribution

In Figure 21, you can see the power supply label containing all the power specs.

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Figure 21: Power supply label

As you can see, this power supply has a single +12 V rail, so there is not much to talk about here.

How much power can this unit really deliver? Let’s find out.

Load Tests

We conducted several tests with this power supply, as described in the article, “Hardware Secrets Power Supply Test Methodology.” 

First we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching the behavior of the reviewed unit under each load. In the table below, we list the load patterns we used and the results for each load.

If you add all the powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (e.g., the +5 V output working at +5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. In the “Total” row, we are using the real amount of power being delivered, as measured by our load tester.

The +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During this test, both inputs were connected to the power supply’s single +12 V rail. (The power supply’s EPS12V connector was installed on the +12VB input of the load tester.)

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	6 A (72 W)	13 A (156 W)	19 A (228 W)	25.5 A (306 W)	32 A (384 W)
+12VB	6 A (72 W)	13 A (156 W)	19 A (228 W)	25.5 A (306 W)	31.5 A (378 W)
+5 V	1 A (5 W)	2 A (10 W)	4 A (20 W)	6 A (30 W)	8 A (40 W)
+3.3 V	1 A (3.3 W)	2 A (6.6 W)	4 A (13.2 W)	6 A (19.8 W)	8 A (26.4 W)
+5VSB	1 A (5 W)	1.5 A (7.5 W)	2 A (10 W)	2.5 A (12.5 W)	3 A (15 W)
-12 V	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)
Total	165.4 W	345.6 W	508.6 W	681.4 W	848.4 W
% Max Load	19.5%	40.7%	59.8%	80.2%	99.8%
Room Temp.	45.0° C	45.5° C	46.9° C	49.4° C	49.0° C
PSU Temp.	48.4° C	48.6° C	49.2° C	50.6° C	52.3° C
Voltage Regulation	Pass	Pass	Pass	Pass	Pass
Ripple and Noise	Pass	Pass	Pass	Pass	Pass
AC Power	187.5 W	382.9 W	570.1 W	777.0 W	990.0 W
Efficiency	88.2%	90.3%	89.2%	87.7%	85.7%
AC Voltage	114.6 V	112.4 V	110.6 V	107.9 V	104.6 V
Power Factor	0.961	0.982	0.991	0.994	0.996
Final Result	Pass	Pass	Pass	Pass	Pass

The 80 Plus Gold certification promises a minimum efficiency of 90% at typical load (i.e., 50% load) and a minimum efficiency of 87% at light (i.e., 20% load) and full loads. The LEPA G850-MAS presented efficiency between 85.7% and 90.3% during our tests. At the full load test, efficiency was below 87%, which can be explained by the AC voltage at our lab that dropped to 104.6 V, and power supplies present lower efficiency at lower AC voltages. Therefore, we can claim the LEPA G850-MAS passed our efficiency tests.

All positive voltages were closer to their nominal values during all tests (3% voltage regulation). The -12 V output was outside this tighter range during tests one through four, but still inside the allowed range. The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values.

Let’s discuss the ripple and noise levels on the next page.

Ripple and Noise Tests

Voltages at the power supply outputs must be as “clean” as possible, with no noise or oscillation (also known as “ripple”). The maximum ripple and noise levels allowed are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures. We consider a power supply as being top-notch if it can produce half or less of the maximum allowed ripple and noise levels.

The LEPA G850-MAS provided low ripple and noise levels, making it a “flawless” unit here.

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	14.2 mV	20.0 mV	28.4 mV	39.4 mV	50.4 mV
+12VB	12.6 mV	17.4 mV	26.8 mV	39.4 mV	52.8 mV
+5 V	10.2 mV	12.6 mV	14.6 mV	18.2 mV	21.2 mV
+3.3 V	12.6 mV	13.8 mV	16.2 mV	18.6 mV	25.2 mV
+5VSB	5.8 mV	6.4 mV	8.4 mV	10.0 mV	13.0 mV
-12 V	52.2 mV	64.4 mV	70.2 mV	70.2 mV	77.8 mV

Below you can see the waveforms of the outputs during test five.

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Figure 22: +12VA input from load tester during test five at 848.4 W (50.4 mV)

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Figure 23: +12VB input from load tester during test five at 848.4 W (52.8 mV)

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Figure 24: +5V rail during test five at 848.4 W (21.2 mV)

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Figure 25: +3.3 V rail during test five at 848.4 W (25.2 mV)

Overload Tests

Below you can see the maximum we could pull from this power supply. The objective of this test is to see if the power supply has its protection circuits working properly. This unit passed this test, as it shut down when we tried to pull more than what is listed in the table below. However, noise and ripple levels were way above the maximum allowed at the +12 V (above 460 mV) and -12 V (above 450 mV) outputs. On the other hand, all positive voltages were still within 3% of their nominal values.

Input	Overload Test
+12VA	33 A (396 W)
+12VB	33 A (396 W)
+5 V	20 A (200 W)
+3.3 V	20 A (66 W)
+5VSB	3 A (15 W)
-12 V	0.5 A (6 W)
Total	956.4 W
% Max Load	112.5%
Room Temp.	46.5° C
PSU Temp.	54.1° C
AC Power	1,147 W
Efficiency	83.4%
AC Voltage	102.6 V
Power Factor	0.996

Main Specifications

The main specifications for the LEPA G850-MAS power supply include:

• Standards: ATX12V 2.3 and EPS12V 2.92
• Nominal labeled power: 850 W
• Measured maximum power: 956.4 W at 46.5° C
• Labeled efficiency: 80 Plus Gold certification
• Measured efficiency: Between 85.7% and 90.3%, at 115 V (nominal, see complete results for actual voltage)
• Active PFC: Yes
• Modular Cabling System: Yes
• Motherboard Power Connectors: One 24-pin connector, two ATX12V connectors that together form an EPS12V connector, and one EPS12V connector, all permanently attached to the power supply
• Video Card Power Connectors: Four six/eight-pin connectors on two cables
• SATA Power Connectors: 12 on three cables
• Peripheral Power Connectors: Four on one cable
• Floppy Disk Drive Power Connectors: One
• Protections (as listed by the manufacturer): Over voltage (OVP), over power (OPP), over temperature (OTP), short-circuit (SCP), and brown-out
• Are the above protections really available? Yes. This unit also has under voltage protection (UVP).
• Warranty: Three years
• Real Model: CWT PUQ750V-G
• More Information: http://www.lepatek.com
• Average Price in the U.S.*: USD 150.00

* Researched at Newegg.com on the day we published this review.

Conclusions

On our tests, the new LEPA G850-MAS presented efficiency between 85.7% and 90.3%, low ripple and noise levels, and all positive voltages were closer to their nominal values than required (3% voltage regulation). However, the most positive point of this power supply is its price, USD 150, which is a terrific price tag for an 850 W power supply with the 80 Plus Gold certification and modular cabling system. Therefore, the LEPA G850-MAS deserves our recommendation.

If you are an observant reader, you will notice that internally, the LEPA G850-MAS is very similar to the Corsair HX 850 W Gold. This similarity, however, is due to the fact that both products are manufactured by the same company, CWT. While Corsair hired CWT to deliver them an exclusive model, LEPA opted for buying a ready-made product. Internally, the Corsair HX 850 Gold uses more powerful active PFC transistors and a higher number of rectifying transistors for the +12 V, +5 V, and +3.3 V outputs. Externally, the model from Corsair provides more cables, including two additional connectors for video cards. Also, we’ve seen lower ripple and noise levels on the Corsair’s model. However, the Corsair model is more expensive. If you won’t need to install three high-end video cards, the LEPA G850-MAS is a terrific option for its price.