Start-up Test

Start-up test is used to detect if the power supply can be initiated normally and if there is destructive voltage overshoot and current overshoot in programmed loading condition.

The electronic load has four basic working modes: CC, CV, CP and CR. Besides, JT63 series electronic load also have the function of real-time displaying the peak voltage (Vp+) to detect if the output voltage of the power supply is overshoot. Moreover, users can also use an oscilloscope and current probe to observe the input current waveform of power supply and observe whether the surge current can cause some destructive effect.

If the measured power supply is CV source, you can use any one of the three modes of CC, CP and CR to make the test. But the principles of the three modes are different. In CR mode, the load will gradually increase the loading current according to the rise of power supply output voltage. Therefore, it has the least impact on the measured power supply. In CC mode, since the electronic load current feedback loop is in the disorder state when the power supply is turned off, the electronic load will starting loading at the maximum current at the moment the power supply is turned on. The duration of this process determines the speed of the feedback loop of the electronic load, so the faster the full range current rising time of electronic load is, the shorter the loading time, caused by the disorder of the feedback loop, is, and the smaller the negative impact on the power supply is. For the same electronic load, loading in CC mode has a stricter requirement to the start-up test than loading in CV mode. In CP mode, the electronic load not only starts loading at the maximum current at the moment the power supply is turned on, but also reduces the loading current to the steady-state value slowly according to the rise of the power supply output voltage. Therefore, loading in CP mode has the strictest requirement to the start-up test. It is recommended that users carefully select the working modes in start-up test according to the characteristics of their power supplies.

In addition, JT63 series electronic load also has Von / Voff function. Once enable Von/Voff function, the electronic load starts loading when the voltage of the power supply rise to the Von set value. Meanwhile, in CC, CP mode, the feedback loop will not be in disorder at the moment of turning on the power supply, thus, the loading transient process at the maximum current will be eliminated.

Note: there might be a big difference between cold start-up and warm start-up in the start-up test of the power supply. Thus, users should make several start-up tests after the power supply is turning off for a different period of time. At least ensure that the start-up test has been made once when the residual charge of the capacitance of the power supply is completely released.