KitGuru KitGuru.net – Tech News | Hardware News | Hardware Reviews | IOS | Mobile | Gaming | Graphics Cards
Advanced Transient Response Tests
For details on our transient response testing, please click here.
These tests are crucial because they simulate the transient loads a PSU is likely to handle (such as booting a RAID array or an instant 100 percent load of CPU/GPUs). We call these “Advanced Transient Response Tests” and they are designed to be very tough to master, especially for a PSU with a capacity of less than 500W.
In all of the tests, we use an oscilloscope to measure the voltage drops caused by the transient load. The voltages should remain within the ATX specification's regulation limits.
We should note that the ATX spec requires for capacitive loading during the transient rests, but in our methodology we chose to apply the worst case scenario with no extra capacitance on the rails.
Advanced Transient Response at 20 Percent – 200ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.090V | 11.859V | 1.91% | Pass |
| 5V | 5.035V | 4.860V | 3.48% | Pass |
| 3.3V | 3.355V | 3.131V | 6.68% | Fail |
| 5VSB | 4.983V | 4.892V | 1.83% | Pass |
Advanced Transient Response at 20 Percent – 20ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.091V | 11.769V | 2.66% | Pass |
| 5V | 5.036V | 4.828V | 4.13% | Pass |
| 3.3V | 3.356V | 3.139V | 6.47% | Fail |
| 5VSB | 4.984V | 4.902V | 1.65% | Pass |
Advanced Transient Response at 20 Percent – 1ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.090V | 11.729V | 2.99% | Pass |
| 5V | 5.036V | 4.839V | 3.91% | Pass |
| 3.3V | 3.356V | 3.100V | 7.63% | Fail |
| 5VSB | 4.985V | 4.860V | 2.51% | Pass |
Advanced Transient Response at 50 Percent – 200ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.047V | 11.923V | 1.03% | Pass |
| 5V | 5.000V | 4.817V | 3.66% | Pass |
| 3.3V | 3.316V | 3.088V | 6.88% | Fail |
| 5VSB | 4.925V | 4.827V | 1.99% | Pass |
Advanced Transient Response at 50 Percent – 20ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.047V | 11.870V | 1.47% | Pass |
| 5V | 5.001V | 4.818V | 3.66% | Pass |
| 3.3V | 3.317V | 3.069V | 7.48% | Fail |
| 5VSB | 4.926V | 4.842V | 1.71% | Pass |
Advanced Transient Response at 50 Percent – 1ms
| Voltage | Before | After | Change | Pass/Fail |
|---|---|---|---|---|
| 12V | 12.047V | 11.892V | 1.29% | Pass |
| 5V | 5.000V | 4.826V | 3.48% | Pass |
| 3.3V | 3.317V | 3.068V | 7.51% | Fail |
| 5VSB | 4.926V | 4.829V | 1.97% | Pass |
Given the not good load regulation we expected to see mediocre results in the transient response tests, and indeed this is the case. Both models are far away from the competition's results. High Power should work on this platform's transient response, since under real life conditions PSUs have to constantly cope with transient loads.
Here are the oscilloscope screenshots we took during Advanced Transient Response Testing:
Transient Response At 20 Percent Load – 200ms
Transient Response At 20 Percent Load – 20ms
Transient Response At 20 Percent Load – 1ms
Transient Response At 50 Percent Load – 200ms
Transient Response At 50 Percent Load – 20ms
Transient Response At 50 Percent Load – 1ms
Turn-On Transient Tests
In the next set of tests, we measure the TPG-750AH3FSGR’s response in simpler transient load scenarios—during its power-on phase.
For our first measurement, we turn the PSU off, dial in the maximum current the 5VSB rail can handle, and switch the power supply back on.
In the second test, we dial the maximum load the +12V rail can handle and start the PSU while it is in standby mode. In the last test, while the PSU is completely switched off (we cut off the power or switch the PSU off through its power switch), we dial the maximum load the +12V rail can handle before restoring power. The ATX specification states that recorded spikes on all rails should not exceed 10 percent of their nominal values (+10 percent for 12V is 13.2V, and 5.5V for 5V).
There is only a small spike at 5VSB, with the rest two test results being almost perfect.
