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Protection Features & DC Power Sequencing
Protection Features
Check out our PSUs 101 article to learn more about PSU protection features. We describe our protection features evaluation methodology in detail here.
| CX450 (CWT) Protection Features | |
|---|---|
| OCP | 12V: 45.2A (120.86%)5V: 32.15A (160.75%)3.3V: 33.85A (169.25%)5VSB: 5.8A (193.33%), 76mV Ripple |
| OPP | 542.026W (120.45%) |
| OTP | ✓ (175°C @ secondary side) |
| SCP | 12V: ✓5V: ✓3.3V: ✓5VSB: ✓-12V: ✓ |
| PWR_OK | Operates properly |
| NLO | ✓ |
| SIP | Surge: MOVInrush: NTC thermistor |
| CX450 (Great Wall) Protection Features | |
|---|---|
| OCP | 12V: 47.4A (126.74%), 12.018V 5V: 32.3A (161.5%), 4.998V 3.3V: 35.3A (176.5%), 3.312V 5VSB: 5.3A (176.67%), 4.919V |
| OPP | 567.995W (126.22%) |
| OTP | ✓ (190°C @ secondary side) |
| SCP | 12V: ✓ 5V: ✓ 3.3V: ✓ 5VSB: ✓ -12V: ✓ |
| PWR_OK | Operates properly |
| NLO | ✓ |
| SIP | Surge: MOV Inrush: NTC thermistor |
It was nice to see over-temperature protection present in these budget-oriented PSUs. Their power-good signals were also accurate (though hold-up time was low in both cases).Both PSUs sport protection features with similar thresholds. The only notable exception is the CWT model's 5VSB rail. OCP (over-current protection) was set pretty high, allowing ripple to get out of control.
DC Power Sequencing (CX450 - Great Wall)
According to Intel’s most recent Power Supply Design Guide (revision 1.4), the +12V and 5V voltages must be equal to or greater than the 3.3V rail’s output at all times.
For our first measurement, we turned the PSU off and switched it back on without any load. Next, we set the PSU to standby mode, dialed full load and then started the PSU. In the last test, while the PSU was completely off (we cut power or switched the PSU off), we dialed full load before restoring power.
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