The constant current electronic load with soft start function is design for LED power supply in this paper. It is used to control the classic simulation constant current load circuit through the constant voltage output circuit by the input voltage of the load terminals V+ and V⁃. In combination with the power⁃on delay start circuit composed of the simple RC delay network, it can make the load current rise slowly from 0mA to the rated current. With the power⁃down fast discharge circuit composed of dual transistors, resistors and capacitors, it can ensure the startup delay effect. The constant current electronic load with soft start function, which dose not need any external power supply, connects directly with the electronic load access voltage to realize pas⁃sive soft start without software delay and other hardware delay. Its advantages are low cost, series and parallel application. In the LED power supply aging test, the soft start constant current electronic load can simulate the LED load instead of the resistance load in order to ensure normal LED power supply testing.% 设计实用于LED电源的，具有缓启动功能的恒流电子负载，利用负载接入端子V+、V-输入电压，经过稳压输出电路稳压后用于控制经典的模拟恒流负载电路，配合上简单的由RC延时网络构成的上电延时启动电路、能使负载电流从0 mA缓慢上升至额定电流，再配合由双三极管及电阻电容构成的掉电快速放电电路，保证了下次启动时的延时效果。该设计的具有缓启动功能的恒流电子负载，无需外部供电，直接取电于负载接入电压，无需软件延时和其他硬件延时，实现无源软缓启动，成本低，可以串联和并联使用。在LED电源的老化测试中，替代电阻负载，模拟LED负载，保证LED电源测试无异常。
展开▼
