Winmate DD-24AX DC-DC Module for Silent, Efficient Power

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TEST RESULTS

The ambient temperature was 22°C, and the ambient noise level was 11 dBA.

TEST A RESULTS
Winmate DD-24AX V220-2 with FSP120-AAB 19VDC 120W Power Adapter
DC Output Voltage (V) + Current (A)
DC Output
AC Input
Calculated Efficiency
Power Factor
+12V1
+5V
+3.3V
-12V
+5VSB
12.30
0.99
5.08
0.97
3.33
0.95
0.1
0.1
22
32
69%
1.0
12.28
1.95
5.08
1.94
3.33
0.94
0.2
0.1
40
53
75%
1.0
12.22
3.88
5.05
1.93
3.33
1.91
0.1
0.1
65
82
80%
1.0
12.16
5.80
5.05
1.93
3.31
1.89
0.2
0.2
90
113
80%
1.0
12.15
7.68
5.02
4.66
3.30
2.73
0.3
0.2
130
169
77%
1.0
Crossload (most output load on 12V line)
12.16
7.81
5.05
0.98
3.33
0.93
0.1
0.1
105
133
79%
1.0
12.18
9.68
5.05
0.98
3.33
0.94
0.1
0.1
128
164
78%
1.0
+12V Ripple on any output line (peak-to-peak): <20mV @ 130W
AC power with no load:
6.3W
AC power when off:
0.8W
NOTE 1: The current and voltage for -12V and +5VSB lines is not measured but based on switch settings. It is a tiny portion of the total, and errors arising from inaccuracies on these lines is <1W.
NOTE 2: The 130W load must be considered a serious overload condition for the FSP power adapter, which is rated for 6.32A maximum. To produce 130W output, the adapter was producing about 7.9A. This was maintained for a little over 5 minutes.

TEST B RESULTS
Winmate DD-24AX V220-2 with Generic 24VDC 180W Power Adapter
DC Output Voltage (V) + Current (A)
DC Output
AC Input
Calculated Efficiency
Power Factor
+12V1
+5V
+3.3V
-12V
+5VSB
12.27
0.97
5.08
0.97
3.33
0.95
0.1
0.1
22
33
66%
0.65
12.27
1.94
5.08
1.94
3.33
0.94
0.2
0.1
40
55
72%
0.70
12.22
3.88
5.05
1.93
3.33
1.89
0.1
0.1
65
86
76%
0.71
12.16
5.78
5.04
1.93
3.31
1.89
0.2
0.2
90
119
75%
0.74
12.14
7.68
5.02
4.66
3.30
2.73
0.3
0.2
130
178
73%
0.76
Crossload (most output load on 12V line)
12.16
7.85
5.05
0.98
3.33
0.93
0.1
0.1
105
138
76%
0.74
12.16
9.63
5.05
0.98
3.33
0.93
0.1
0.1
127
171
74%
0.76
+12V Ripple on any output line (peak-to-peak): <20mV @ 130W
AC power with no load:
6.3W
AC power when off:
1.3W
NOTE: The current and voltage for -12V and +5VSB lines is not measured but based on switch settings. It is a tiny portion of the total, and errors arising from inaccuracies on these lines is <1W.

Comparing the two sets of results, let's look first at the commonalities:

1. Voltage Regulation was excellent, and quite similar with both adapters. The 12V line varied a maximum of 0.15V with either adapter, which is just 1.25%. The 5V line varied just .03V, and the 3.3V line was rock solid.

2. Ripple and noise was very low, about 16mV at the highest peak seen with either adapter on any voltage line. This is excellent.

Both of the above results can be attributed to the Winmate DD-24AX, which regulates all the output voltage lines. This is a major difference between the Winmate DD-24AX and the picoPSU: The latter simply passes the 12V line through from its input. In other words, the 12VDC line is filtered, regulated and protected by the Winmate, while the 12VDC line in the picoPSU is entirely dependent on the quality of the 12VDC adapter feeding its input. For this reason, the picoPSU cannot be considered as secure or reliable a power supply as the Winmate DD-24AX.

3. There was no significant noise from either of the adapters, with any load or plugged in without any load — the buzzing or whining that can occur under the latter condition is a serious problem with some adapters.

4. The DD-24AX made no audible noise at any load.

5. Starting with no load was no problem with either adapter, at the same 6.3W AC power draw.

6. When turned off but still plugged in, the AC power draw was low, slightly lower for the FSP.

Now, consider the differences:

7. Efficiency: By now, most SPCR readers know that this is a measure of AC-to-DC conversion efficiency. The ATX12V Power Supply Design Guide recommends 80% efficiency or better at all output power loads. 80% efficiency means that to deliver 80W DC output, a PSU draws 100W AC input, and 20W is lost as heat within the PSU. Higher efficiency is preferred for reduced energy consumption and cooler operation.

At the super low 22W load, efficiency was quite good with either adapter. But as the load was increased, efficiency with the FSB rose quickly, reaching 75% at just 40W, and the high of 80% by 65W and staying there to about 100W. The 40W~65W efficiency performance can only be matched by Bronze (or higher) 80 Plus ATX12V PSUs. By contrast, with the generic 24VDC adapter, efficiency peaked at 76% at 65W and fell beyond that point. This is bettered by most 80 Plus approved power supplies.

Accepting the claimed 88% efficiency for the Winmate DD-24AX, the efficiency of the power adapters can be calculated:

Estimated Efficiency of Power Adapters
(assuming 88% efficiency in DD-24AX V220-2)
Load
FSP120-AAB adapter
Generic 24VDC adapter
22
78%
75%
40
85%
82%
65
91%
86%
90
91%
85%
130
88%
83%

It's obvious that the FSP is a much more efficient adapter. At 130W load, when the FSP adapter was in overload by at least 20W, the efficiency was still an estimated 88%. The droop at the extremes for both adapters may be a bit exaggerated; the DC/DC converter surely must vary in its efficiency as well, and run slightly less efficiently at very high and very low loads.

Given that FSP only rates this adapter to be better than 86% efficient, it's possible that the 88% efficiency spec of the Wingate is conservative. It could easily be higher. In any case, since the FSP adapter is claimed to be 86% efficient and the Winmate board is claimed to be 88% efficient, the combined claimed efficiency of the two together amounts to 75%. The test results show better efficiency than this for most of the operating range, so the claim of the Winmate board is verified.

It's also possible that the Winmate DD-24AX is more efficient with 19VDC input than with 24VDC; this cannot be determined SPCR's existing power testing gear.

EFFICIENCY UPDATE - Oct 28/09

After some experimentation with the SPCR power supply test system, a way to measure the energy efficiency of the power adapters was established. This methodology has to be refined, but the preliminary results look accurate. The FSP120-AAB adapter was found to have about 86~89% efficiency. This suggests that the Winmate DD-24AX V220-2 has a much higher efficiency than 88%. At the high point of the curve, it appears to be at least 93% efficient, and the 88% figure can be regarded as a worst case.

More on all this to come later, as a method of directly measuring the efficiency of the Winmate DC/DC adapter is being devised.

8. Power Factor is ideal when it measures 1.0. In the most practical sense, PF is a measure of how "difficult" it is for the electric utility to deliver the AC power into your power supply. High PF reduces the AC current draw, which reduces stress on the electric wiring in your home (and elsewhere up the line). It also means you can do with a smaller, cheaper UPS backup; they are priced according to their VA (volt-ampere) rating. Power factor with the FSP was as good as it can be in every state. With the generic 24V adapter, it was mediocre and never went above 0.76.

9. Temperature data was not put into a table because readings were made with an infrared hand-held thermometer at many points. The DC/DC board was checked for temperature after about 5 minutes at full load. With the 24VDC adapter, the single hottest point on the Winmate DD-24AX was the large coil at the power input, which reached over 65°C at full load. Most of the other components were substantially lower, varying from 30°C to about 55°C. With the FSP adapter, the temperature of the big coil was ~15°C lower. The 24VDC adapter itself ran considerably hotter, reaching nearly 50°C in some spots. The FSB, in contrast, measured under 40°C throughout testing.



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