Spire BlackDragon 400 W Power Supply Review
By Gabriel Torres on September 13, 2012


Introduction

Spire provides three models within its BlackDragon series: 400 W, 500 W, and 600 W. None of them has the 80 Plus certification. Let’s see if the 400 W model is a good buy.

Units from the BlackDragon series are manufactured by Seventeam

Spire Black Dragon 400w
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Figure 1: Spire BlackDragon 400 W power supply

Spire Black Dragon 400w
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Figure 2: Spire BlackDragon 400 W power supply

The Spire BlackDragon 400 W is 5.5” (140 mm) deep, using a 120 mm fan on its bottom (no indication of the manufacturer).

Spire Black Dragon 400w
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Figure 3: Fan

The unit doesn’t have a modular cabling system, and all cables are protected with nylon sleeves, which come from inside the unit. This power supply comes with the following cables:

All wires are 18 AWG, which is the correct gauge to be used

The number of connectors is adequate for an entry-level 400 W power supply.

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Figure 4: Cables

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

A Look Inside the Spire BlackDragon 400 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.

Spire Black Dragon 400w
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Figure 5: Top view

Spire Black Dragon 400w
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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 one X capacitor and two Y capacitors 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 Spire BlackDragon 400 W.

Primary Analysis

On this page, we will take an in-depth look at the primary stage of the Spire BlackDragon 400 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses one GBU808 rectifying bridge, which is attached to the same heatsink used by the components from the active PFC circuit. This bridge supports up to 8 A at 100° C. In theory, you would be able to pull up to 920 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 736 W without burning itself out. Of course, we are only talking about this particular component. The real limit will depend on all the components combined in this power supply.

Spire Black Dragon 400w
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Figure 11: Rectifying bridge

The active PFC circuit uses two FDPF18N50 MOSFETs, each one supporting up to 18 A at 25° C or 10.8 A at 100° C in continuous mode (note the difference temperature makes), or 72 A at 25° C in pulse mode. These transistors present a 265 mΩ maximum 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: The active PFC transistors and diode

The output of the active PFC circuit is filtered by one 220 µF x 420 V electrolytic capacitor from CapXon, labeled at 85° C.

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Figure 13: Capacitor

In the switching section, two FQPF12N60 MOSFETs are employed using the traditional two-transistor forward configuration. Each transistor supports up to 5.8 A at 25° C or 3.7 A at 100° C in continuous mode or up to 23 A at 25° C in pulse mode, with a maximum RDS(on) of 700 mΩ.

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Figure 14: The switching transistors

The switching transistors and active PFC circuit are controlled by the omnipresent CM6800 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 Spire BlackDragon 400 W uses a regular design in its secondary, with Schottky rectifiers.

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 two PFR30L60CT Schottky rectifiers, each supporting up to 30 A (15 A per internal diode at 110° C, maximum voltage drop of 0.60 V), giving us a maximum theoretical current of 43 A or 514 W for this output.

The +5 V output uses one PFR30V30CT Schottky rectifier, which supports up to 30 A (15 A per internal diode at 90° C, maximum voltage drop of 0.44 V), giving us a maximum theoretical current of 21 A or 257 W for this output.

The +3.3 V output uses two PFR30V45CT Schottky rectifiers, each supporting up to 30 A (15 A per internal diode at 110° C, maximum voltage drop of 0.47 V), giving us a maximum theoretical current of 43 A or 141 W for this output.

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Figure 16: The +3.3 V, +5 V, and +12 V rectifiers

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

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Figure 17: Monitoring circuit

The electrolytic capacitors available in the secondary are also from CapXon, and labeled at 105° C, as usual.

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Figure 18: Capacitors

Power Distribution

In Figure 19, you can see the power supply label containing all the power specs.

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Figure 19: Power supply label

According to the manufacturer, this unit has two +12 V rails. However, this information is false, since inside the unit all yellow (+12 V) wires are connected to a single point, and the monitoring circuit doesn’t have over current protection, which is a prerequisite to support multiple +12 V rails. Click here to learn more about this subject.

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 and +12VB inputs were connected to the power supply’s single +12 V rail. (The +12VB input was connected to the power supply EPS12V connector.)

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

2.5 A (30 W)

5.5 A (66 W)

8 A (96 W)

10.5 A (126 W)

13.5 A (162 W)

+12VB

2.5 A (30 W)

5.5 A (66 W)

8 A (96 W)

10.5 A (126 W)

13 A (156 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

80.1 W

158.2 W

241.4 W

320.4 W

401.4 W

% Max Load

20.0%

39.6%

60.4%

80.1%

100.4%

Room Temp.

44.8° C

43.1° C

43.0° C

43.7° C

45.6° C

PSU Temp.

47.3° C

45.4° C

45.0° C

45.9° C

47.9° C

Voltage Regulation

Pass

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

Failed at +3.3 V and +5VSB

AC Power

102.9 W

190.4 W

290.9 W

391.3 W

501.7 W

Efficiency

77.8%

83.1%

83.0%

81.9%

80.0%

AC Voltage

117.5 V

118.3 V

117.2 V

116.5 V

115.4 V

Power Factor

0.983

0.98

0.988

0.991

0.994

Final Result

Pass

Pass

Pass

Pass

Fail

Since this power supply didn’t receive the 80 Plus certification, we were not worried about the efficiency below 80% during our test one, with the power supply delivering 80 W. Except for this load, efficiency was good for an entry-level unit, even though the manufacturer promises 86% efficiency, which we didn’t see.

All positive voltages were closer to their nominal values than required (3% regulation), which is excellent. The -12 V output was outside this tighter range, but was 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 Spire BlackDragon 400 W presented noise and ripple levels above the maximum allowed at +3.3 V and +5VSB when delivering 400 W. From our experience, the high jump in noise and ripple from our test four to test five indicates that the unit had surpassed its operating limits. This is not surprising given Spire’s reputation for buying power supplies from Seventeam and labeling them at wattages higher than Seventeam’s intended wattage.

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

13.2 mV

11.2 mV

10.4 mV

15.4 mV

23.8 mV

+12VB

19.6 mV

11.4 mV

18.4 mV

24.8 mV

33.2 mV

+5 V

10.8 mV

8.4 mV

9.8 mV

12.2 mV

14.2 mV

+3.3 V

15.0 mV

9.8 mV

13.4 mV

20.2 mV

54.6 mV

+5VSB

15.2 mV

11.0 mV

16.4 mV

30.2 mV

119.6 mV

-12 V

19.4 mV

13.2 mV

21.6 mV

26.8 mV

30.2 mV

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

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Figure 20: +12VA input from load tester during test five at 401.4 W (23.8 mV)

Spire Black Dragon 400w
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Figure 21: +12VB input from load tester during test five at 401.4 W (33.2 mV)

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Figure 22: +5V rail during test five at 401.4 W (14.2 mV)

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Figure 23: +3.3 V rail during test five at 401.4 W (54.6 mV)

Let’s see if we can pull more than 400 W from this unit.

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, noise and ripple levels were way above the maximum allowed at +3.3 V (at 143.8 mV), +5VSB (at 145.6 mV), and -12 V (at 125.4 mV) outputs. Voltages were below the minimum allowed at +12VA (+10.89 V), +12VB (+10.43 V), and +5 V (+4.53 V), and above the maximum allowed at -12 V (-10.43 V). It is clear that the protection that kicked in was the under voltage protection (UVP), and the unit was operating way above its limits.

Input

Overload Test

+12VA

18 A (216 W)

+12VB

18 A (216 W)

+5 V

8 A (40 W)

+3.3 V

8 A (26.4 W)

+5VSB

3 A (15 W)

-12 V

0.5 A (6 W)

Total

515.8 W

% Max Load

129.0%

Room Temp.

48.2° C

PSU Temp.

49.4° C

AC Power

680.0 W

Efficiency

75.9%

AC Voltage

113.7 V

Power Factor

0.995

Main Specifications

The main specifications for the Spire BlackDragon 400 W power supply include:

Conclusions

At first glance, the Spire BlackDragon 400 W looks like a good entry-level power supply, with a good cable configuration and the manufacturer promising 86% efficiency.

Efficiency was between 77.8% and 83.1% on our tests. It’s not as high as promised by the brand, but it is good enough for an entry-level power supply. Voltage regulation was very good, with all positive voltages within 3% of their nominal values, while the ATX12V specification allows for a 5% margin. Noise and ripple levels were very low when we pulled up to 80% of the power supply labeled wattage, i.e., up to 320 W.

At 400 W, noise and ripple levels skyrocketed, which usually means the power supply surpassed its operating limits. Due to Spire’s reputation for buying power supplies from Seventeam and adding 50 to 100 more watts to the original label (click here to read the full story), we wouldn’t be surprised if this unit was originally a 350 W unit relabeled to 400 W.

Even though we know that entry-level systems won’t pull anything closer to 400 W, we can’t recommend this unit. The fact that it has a suggested price of USD 80 makes our non-recommendation easier. For less than that, you can buy the new Seasonic G-360, which is a vastly superior unit for the savvy user building an entry-level PC.

Originally at http://www.hardwaresecrets.com/article/Spire-BlackDragon-400-W-Power-Supply-Review/1635


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