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Protection Features, DC Power Sequencing, Cross-Load Tests and Infrared Images

Protection Features

Check out our PSUs 101 article to learn more about PSU protection features.

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Protection Features	-
OCP (Cold @ 25.5°C)	12V: 68A (108.8%), 11.95V 5V: 26.5A (132.5%), 4.938V 3.3V: 28A (140%), 3.278V 5VSB: 3.8A (152%), 5.025V
OCP (Hot @ 38°C)	12V: 66.2A (105.92%), 11.959V 5V: 25.6A (128%), 4.944V 3.3V: 27.1A (135.5%), 3.281V 5VSB: 3.9A (156%), 5.018V
OPP (Cold @ 27°C)	882.2W (117.63%)
OPP (Hot @ 41°C)	869.59W (115.94%)
OTP	✓ (155°C @ 12V Heat Sink)
SCP	12V to Earth: ✓ 5V to Earth: ✓ 3.3V to Earth: ✓ 5VSB to Earth: ✓ -12V to Earth: ✓
PWR_OK	Accurate but lower than 16ms
NLO	✓
SIP	Surge: MOV Inrush: NTC Thermistor

OCP at 12V and 5V and OPP are configured correctly. We would like to see lower OCP, though, at 3.3V. OTP is also present, and this is a major advantage.

DC Power Sequencing

According to Intel’s most recent Power Supply Design Guide (revision 1.4), the +12V and 5V outputs must be equal to or greater than the 3.3V rail at all times. Unfortunately, Intel doesn't mention why it is so important to always keep the 3.3V rail's voltage lower than the levels of the other two outputs.

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Thermaltake Smart BM2 750W — (Image credit: Tom's Hardware)

DC Power Sequencing Scope Shots

The 3.3V rail is always lower than the other two, as the ATX spec dictates.

Cross Load Tests

To generate the following charts, we set our loaders to auto mode through custom-made software before trying more than 25,000 possible load combinations with the +12V, 5V, and 3.3V rails. The deviations in each of the charts below are calculated by taking the nominal values of the rails (12V, 5V, and 3.3V) as point zero. The ambient temperature during testing was between 30 to 32 degrees Celsius (86 to 89.6 degrees Fahrenheit).

Load Regulation Charts

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Load Regulation Graphs

Efficiency Graph

Ripple Graphs

The lower the power supply's ripple, the more stable the system will be and less stress will also be applied to its components.

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Ripple Suppression Graphs

Infrared Images

We apply a half-load for 10 minutes with the PSU's top cover and cooling fan removed before taking photos with a modified FLIR E4 camera able to deliver an IR resolution of 320x240 (76,800 pixels).

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