Research And Design Of Long Lifetime AD-DC Pulse Drive Power Supplies For LED Lighting Without Electrolytic Capacitor

Because of the long lifetime, low power consumption and green to the environment, LED has widely used in the roads, tunnels and buildings. The lifetime of LED is nearly50000hours and is related to the temperature. As the development of heat dissipation, the lifetime of LED will be longer. However, the lifetime of LED power driver is less than10000hours, which is limited by the electrolytic capacitor. Because the electrolytic capacitor is used to store energy and its lifetime is about5000hours to10000hours. So the difference of lifetime between LED and electrolytic capacitor make the lifetime of LED power driver shorter, which will waste the resource.In consideration of cost, the other capacitor can’t replace electrolytic capacitor, and the inductor also cannot replace the electrolytic capacitor to store energy. So we must drive LED by no electrolytic capacitor. As the AC power input, we use the pulse current to drive the LED without the electrolytic capacitor. In this paper, we come up with a new technology to drive the LED with pulse current. The main research work is introduced below:First, we analysis the recent LED drive power supply technology and the structure and operation principle of the circuit of stable current and stable voltage. Finally we come up with the LED pulse drive power supply without electrolytic capacitor. This project has got rid of influence of lifetime by the electrolytic capacitor. Second, with the help of saber, we simulate the main circuit to make sure the project is right. Adjustment some parameters, so that the result of the simulation will be much closer to the design。Then, make sure the circuit work well and stable, and in consideration of the cost, we simplify the structure of the circuit. Meanwhile, we design an accessory power to supply for the chip and control circuit. At last, in order to protect the whole circuit from damage after the LED break down, we design another protective circuitFinally, we do experiments based on the structure and operational principle which are introduced before. During the experiment, we adjust the structure of the circuit and some parameters of components. After the experiment, we determine the parameters of all the components and make PCB. At last, basing on the experiment of PCB, we check the project and obtain some useful wave profiles and date.