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Protection Features & DC Power Sequencing

Protection Features

Check out our PSUs 101 article to learn more about PSU protection features. Our protection features evaluation methodology is described in detail here.

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Protection Features
OCP	12V: 91A (130%), 12.157V 5V: 25.7A (128.5%), 5.023V 3.3V: 25.3A (126.5%), 3.33V 5VSB: 5.1A (170%), 5.005V
OPP	1107.7W (130.32%)
OTP	✓ (170°C @ 12V heat sink)
SCP	12V: ✓ 5V: ✓ 3.3V: ✓ 5VSB: ✓ -12V: ✓
PWR_OK	Operates properly
NLO	✓
SIP	Surge: MOV Inrush: NTC thermistor & bypass relay

The over-current protection feature's triggering point at +12V, 5V, and 3.3V is properly set at 130% and below. While it's much higher at 5VSB, this is fine with us since we don't measure increased ripple and the voltage is within spec.

Over-power protection is right on target at 130%, while over-temperature protection gets activated once the +12V rail reaches 170°C.

The power-good signal is accurate, and inrush current protection includes an NTC thermistor and a bypass relay.

DC Power Sequencing

According to Intel’s most recent Power Supply Design Guide (revision 1.4), the +12V and 5V voltages must be equal or greater than the 3.3V rail’s output during power-up and normal operation.

For our first measurement, we turn the PSU off and switch it back on without any load. In the second test, we operate the PSU in standby mode, dial in a full load, and start the PSU. In the last test, while the PSU is completely switched off, we set a full load before restoring power.

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