Protection Features Evaluation

With the exception of the 5VSB rail, OCP is properly set. We don't mind the high OCP triggering point at 5VSB since load regulation and ripple suppression are good. Over power protection is adequately configured at close to 130% of the unit's maximum power, while the triggering point for over temperature protection looks low. We usually measure 150–170 °C on the +12V heatsink before OTP intervenes.

The power_ok signal is accurate, and there is surge and high inrush current protection. Inrush current protection uses both the necessary NTC thermistor and a relay, which allows the thermistor to quickly cool down and simultaneously boosts efficiency since no power is wasted on the thermistor once the start-up phase finishes.

DC Power Sequencing

According to Intel's most recent Power Supply Design Guide (revision 1.4), the +12V and 5V rails must have voltages equal to or greater than the 3.3V rail's output at all times during the power-up phase and regular operation. For our first measurement, we turn the unit off and switch it back on without any load on any of the rails.

EMI Results - AVG and Detector