CV mode load of electronic load, is the basis of LED power test. CV is the constant voltage, but just load current tensile load of equipment, itself can not provide constant voltage. Therefore, the so-called CV, just through the voltage negative feedback circuit, servo LED power supply output current changes and make the LED on the output capacitor charge balance, so as to achieve the purpose of constant voltage.

When the LED power supply output current ripple frequency is very high, if the load is insufficient bandwidth to servo current changes and caused shock, when the shock occurs, load input voltage change sharply, LED output capacitor to frequent high current charge and discharge, at this time the detection of electric rhyolitic wave will be greater than the steady state of the LED power supply when the actual current ripple.

When the load of insufficient bandwidth, if the LED power supply output capacitance is large enough, then the volatility can also control in the acceptable range, but it is a pity, LED power supply price competition is very fierce, output capacitance is generally insufficient. Therefore, the LED power supply tested on load bandwidth requirements are very harsh.

The bandwidth of the load index, manufacturers are not directly labeled, can only refer to another indicator: the full range of current rise time, it is clear that the full range of current rise time is smaller, indicating that the bandwidth of the load is higher. Constant current rise full bandwidth and load is high, the LED power supply output capacitance is low, generally speaking, 10uS range of the time load and can meet most of the LED power supply testing is required, but in theory, any load in the CV model, shock possible. In this case, when the LED output capacitance, load bandwidth is high, the shock amplitude is smaller, the test results of confidence is high, therefore, users in the use of electronic load test, we must pay close attention to the load input voltage ripple VPP changes, once it is beyond the scope of the test result can't be trusted. This point is very important.

Based on the above analysis, LED power supply test, the load has harsh requirements, mainly in the following points: the full-scale current rise time is fundamental to ensure accurate load, this value is lower, the better; the sampling rate of the data is to ensure the accurate measurement of the basic, the value, the higher the better; VPP real time display, is trusted to determine whether the measured data; filtering speed regulating function is to get stable current data of small means;

The most simple way to increase the filtering intensity, forced to make data stable. Simple use of this method, very easy to cause a miscarriage of justice, causing quality accidents.