In Win GreenMe 750 W Power Supply Review
By Gabriel Torres on May 4, 2012


Introduction

Hardware Secrets Silver Award

The new GreenMe power supply series from In Win will arrive on the market in June, in 550 W, 650 W, and 750 W versions, all with the 80 Plus Bronze certification. In a very different move, In Win committed to donate USD 1.00 to the World Wildlife Foundation (WWF) for every GreenMe unit sold. Let’s see if the 750 W model will be a good buy.

In Win GreenMe 750 W power supply
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Figure 1: In Win GreenMe 750 W power supply

In Win GreenMe 750 W power supply
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Figure 2: In Win GreenMe 750 W power supply

The In Win GreenMe 750 W is 5.5” (140 mm) deep, using a 120 mm ball bearing fan on its bottom (ADDA AD1212LB-A70GL).

The reviewed power supply doesn’t have a modular cabling system. All cables are protected with nylon sleeves that come from inside the unit. This power supply comes with the following cables:

All wires are 18 AWG, which is the minimum recommended gauge. The number of connectors available is lower than we expected for a 750 W product. It would be better if the unit had four cables for video cards instead of only two, which would allow the out-of-the-box installation of two high-end video cards that require two power connectors each.

In Win GreenMe 750 W power supply
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Figure 3: Cables

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

A Look Inside the In Win GreenMe 750 W

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.

In Win GreenMe 750 W power supply
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Figure 4: Top view

In Win GreenMe 750 W power supply
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Figure 5: Front quarter view

In Win GreenMe 750 W power supply
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Figure 6: Rear quarter view

In Win GreenMe 750 W power supply
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Figure 7: 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 one X capacitor more than the minimum required, and with two additional Y capacitors and one additional X capacitor after the rectifying bridge.

In Win GreenMe 750 W power supply
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Figure 8: Transient filtering stage (part 1)

In Win GreenMe 750 W power supply
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Figure 9: Transient filtering stage (part 2)

On the next page, we will have a more detailed discussion about the components used in the In Win GreenMe 750 W.

Primary Analysis

On this page we will take an in-depth look at the primary stage of the In Win GreenMe 750 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses two GBU805 rectifying bridges, which are attached to the same heatsink as the active PFC and switch transistors. 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, the bridges would allow this unit to deliver up to 1,472 W without burning themselves out. Of course, we are only talking about these particular components. The real limit will depend on all the components combined in this power supply.

In Win GreenMe 750 W power supply
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Figure 10: Rectifying bridges

The active PFC circuit uses two SPW21N50C3 MOSFETs, each supporting up to 21 A at 25° C or 13.1 A at 100° C in continuous mode (see the difference temperature makes) or 63 A at 25° C in pulse mode. These transistors present a 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.

The output of the active PFC circuit is filtered by one 470 µF x 450 V Japanese electrolytic capacitor, from Panasonic, labeled at 105° C.

In the switching section, two TK20J50D MOSFETs are employed using the traditional two-transistor forward configuration. Each of these transistors supports up to 20 A at 25° C in continuous mode or up to 80 A at 25° C in pulse mode, with a maximum RDS(on) of 270 mΩ. Unfortunately, the manufacturer doesn’t publish the current limits at 100° C.

In Win GreenMe 750 W power supply
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Figure 11: One of the active PFC transistors and the two switching transistors

The primary is managed by a CM6802 active PFC/PWM combo controller.

In Win GreenMe 750 W power supply
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Figure 12: Active PFC/PWM combo controller

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

Secondary Analysis

The In Win GreenMe 750 W uses a DC-DC design in its secondary. This means that the power supply is basically a +12 V unit, with the +5 V and +3.3 V outputs produced by two smaller power supplies connected to the main +12 V rail. This design is used to increase efficiency.

The maximum theoretical current that each line can deliver is given by the formula I / (1 - D) where D is the duty cycle used and I is the maximum current supported by the rectifying diode. As an exercise, we can assume a duty cycle of 30 percent.

The +12 V output uses four PFR40L60PT Schottky rectifiers, each supporting up to 40 A (20 A per internal diode at 110° C with a 0.65 V maximum voltage drop). This gives us a maximum theoretical current of 114 A or 1,371 W for the +12 V output. However, keep in mind that the +5 V and the +3.3 V outputs are generated from the +12 V output.

In Win GreenMe 750 W power supply
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Figure 13: Two of the four +12 V rectifiers and the +5VSB rectifier

As explained, the +5 V and +3.3 V outputs are produced by two DC-DC converters. Each is located on a small daughterboard soldered to the main printed circuit board. In Figures 14 and 15, you can see the physical aspect of one of these converters. Each is controlled by a uP3872B integrated circuit, using two QM3004D (marked “M3004D”) and two QM3016D (marked “M3016D”) MOSFETs. Each QM3004D supports up to 55 A at 25° C or 40 A at 100° C in continuous mode or up to 110 A at 25° C in pulse mode, with an RDS(on) of 8.5 mΩ, while each QM3016D supports up to 96 A at 25° C or 68 A at 100° C in continuous mode or up to 192 A at 25° C in pulse mode, with an RDS(on) of 4 mΩ.

In Win GreenMe 750 W power supply
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Figure 14: One of the DC-DC converters

In Win GreenMe 750 W power supply
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Figure 15: One of the DC-DC converters

This power supply uses a WT7579 monitoring integrated circuit. This chip supports over voltage (OVP), under voltage (UVP), over current (OCP), and over temperature (OTP) protections. There are four +12 V over current protection (OCP) channels, matching the number of +12 V rails advertised by the manufacturer.

In Win GreenMe 750 W power supply
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Figure 16: Monitoring circuit

The electrolytic capacitors that filter the outputs are from Teapo and Samxon and labeled at 105° C, as usual.

Power Distribution

In Figure 17, you can see the power supply label containing all the power specs.

In Win GreenMe 750 W power supply
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Figure 17: Power supply label

This power supply is advertised as having four +12 V rails, which is correct, since the monitoring integrated circuit has four +12 V over current protection (OCP) channels, and we clearly saw four current sensors (“shunts”) on the solder side of the printed circuit board. See Figure 18. Click here to understand more about this subject.

In Win GreenMe 750 W power supply
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Figure 18: Shunts

The four +12 V rails are distributed as follows:

This distribution is perfect.

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, the +12VA input was connected to the power supply +12V1 and +12V3 rails, while the +12VB input was connected to the power supply +12V2 rail.

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

5.5 A (66 W)

11 A (132 W)

16.5 A (198 W)

21.5 A (258 W)

27.5 A (330 W)

+12VB

5.5 A (66 W)

11 A (132 W)

16 A (192 W)

21.5 A (258 W)

27.5 A (330 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

152.9 W

296.4 W

446.9 W

583.7 W

748.8 W

% Max Load

20.4%

39.5%

59.6%

77.8%

99.8%

Room Temp.

45.3° C

45.3° C

48.2° C

44.8° C

45.6° C

PSU Temp.

44.6° C

45.2° C

47.1° C

50.1° C

51.1° C

Voltage Regulation

Pass

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

Fail at -12 V

AC Power

176.1 W

338.3 W

519.3 W

691.0 W

914.0 W

Efficiency

86.8%

87.6%

86.1%

84.5%

81.9%

AC Voltage

115.8 V

114.0 V

111.1 V

111.0 V

108.4 V

Power Factor

0.963

0.975

0.985

0.987

0.992

Final Result

Pass

Pass

Pass

Pass

Pass

On our tests, the In Win GreenMe 750 W presented efficiency between 81.9% and 87.6%, matching the 80 Plus Bronze certification, which promises a minimum efficiency of 82% at light (i.e., 20%) and full loads, and 85% at typical (i.e., 50%) load.

Voltage regulation was excellent, with all voltages closer to their nominal values (3% regulation) during all tests. The only exception was the +5VSB output during test five, which was at +4.80 V, still inside the proper 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 In Win GreenMe 750 W provided ripple and noise levels inside the specification; however, the -12 V output was out of proper range during test five. Also, the noise levels at the +12 V outputs were a little bit high for us to consider this unit “flawless.” See the table below.

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

13.2 mV

18.6 mV

22.6 mV

42.6 mV

74.4 mV

+12VB

16.4 mV

20.8 mV

25.8 mV

45.4 mV

82.8 mV

+5 V

16.2 mV

15.6 mV

15.6 mV

16.4 mV

17.6 mV

+3.3 V

10.8 mV

11.8 mV

13.6 mV

17.2 mV

22.0 mV

+5VSB

11.0 mV

11.2 mV

11.4 mV

16.6 mV

26.4 mV

-12 V

45.4 mV

57.4 mV

75.2 mV

94.2 mV

126.8 mV

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

In Win GreenMe 750 W power supply
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Figure 19: +12VA input from load tester during test five at 748.8 W (74.4 mV)

In Win GreenMe 750 W power supply
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Figure 20: +12VB input from load tester during test five at 748.8 W (82.8 mV)

In Win GreenMe 750 W power supply
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Figure 21: +5V rail during test five at 748.8 W (17.6 mV)

In Win GreenMe 750 W power supply
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Figure 22: +3.3 V rail during test five at 748.8 W (22.0 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, since it shut down when we tried to pull more than what is listed below. During this test, the +3.3 V output presented a voltage below the minimum allowed, at +3.13 V, while noise and ripple levels were above the maximum allowed at +12VB (120.4 mV) and -12 V (168.8 mV).

Input

Overload Test

+12VA

32 A (384 W)

+12VB

32 A (384 W)

+5 V

12 A (60 W)

+3.3 V

12 A (39.6 W)

+5VSB

3 A (15 W)

-12 V

0.5 A (6 W)

Total

876.8 W

% Max Load

116.9%

Room Temp.

44.8° C

PSU Temp.

56.4° C

AC Power

1,127.0 W

Efficiency

77.8%

AC Voltage

104.8 V

Power Factor

0.995

Main Specifications

The main specifications for the In Win GreenMe 750 W power supply include:

Conclusions

The In Win GreenMe 750 W is a fair power supply, with efficiency between 81.9% and 87.6%, three percent voltage regulation, and noise and ripple inside the allowed range, except for the -12 V output when the power supply is delivering 750 W. Another problem with this power supply, in our opinion, is the presence of only two video card power connectors. We think 750 W power supplies should come with four of them in order to allow you to connect two high-end video cards without the need of adapters.

Although not perfect, the In Win GreenMe 750 W is not a “bad” power supply, and it is priced correctly, as most 750 W power supplies that are better cost at least USD 15 (i.e., 15%) more.

In summary, if you are an average user looking for an affordable 750 W power supply with the 80 Plus Bronze certification, the In Win GreenMe may be an option. However, for the same price, you can buy the OCZ Fatal1ty 750 W, which comes with a modular cabling system but has a little lower efficiency. If you prefer to buy a “flawless” unit, you will have to spend more money and pick a different product. (Check the XFX PRO 750 W and the Enermax NAXN 82+ 750 W.) 

 

Originally at http://www.hardwaresecrets.com/article/In-Win-GreenMe-750-W-Power-Supply-Review/1546


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