Design And Research On LED Lighting Switching Power Supply

In the case of the global energy crisis greatly, global energy are scarce, in the face of this situation, energy conservation and environmental protection is an important direction in the kinds of developments, in the lighting industry, LED lighting is energy saving and environmental protection, now the range of LED lighting is becoming more and more widely. In "green energy" mentioned, the LED lighting switch power efficiency is very high, and the main reason is the greatest degree of energy saving and environmental protection. Due to the applications of LED lighting are wide and a large quantity, this situation can significantly reduce the required energy, also reduces the amount of power plants, reducing the power plant emissions of waste water and dust pollution to the environment. LED lighting switch with high efficiency, small volume and light weight and is safe and reliable.So LED lighting switch power technology has become a hot spot in research and development faster and faster.This paper gives the LED lighting switch power supply background, introduces the development status at home and abroad, as well as the LED switch power supply driving practical research significance. We first introduced the driving method of LED switching power supply. In this paper we drive LED with electric and the integrated circuit for direct drive circuit. We introduces the technology of power factor correction, three kinds of power factor correction technology are now more application, namely the passive power factor correction technology, single-stage active power factor correction technique and bipolar active power factor correction technique, then these kinds of power factor correction are introduced and compared. On the choice of main circuit topology, in detail introduces the flyback switch transform circuit, forward converter,push pull switch transform circuit, the whole bridge conversion circuit topology circuit structure have carried on the contrast. The space and cost can be saved. We used the single stage active power factor controller, the main circuit adopts flyback converter circuit.In accordance with the requirements of the design of LED high frequency switching power supply main chip, we use L6562as the control chip. Using the flyback type transform topology, and the critical conduction mode.L6562control chip internal integrates the driver output module, current comparator and PWM latch, TM (critical) mode PFC power factor correction. L6562. in a single level structure not only realizes the power factor correction, and completes the DC/DC level of blood pressure and high and low voltage electrical isolation. The power supply can provide constant current for LED, which ensures that LED brightness stability. In this article we have carried on the flyback transformer in detail. The flyback transformer has functions of energy storage, current limiting and isolation. In the size of the magnetic core, the original side inductance, the air gap size, the former vice edge coil number of turns of the selection calculation, duty ratio calculation and so on all has carried on the detailed consideration. The design of EMI suppression circuit has been down, so that the efficiency of LED lighting switch power supply in this thesis can be as high as88%, to improve the reliability of electric power.Combined with the introduction of the above, this paper designs a wide input voltage range of90～265Vac,50W lighting LED switching power supply, including the design of the RCD buffer, based on the single stage L6562active power factor correction circuit and main circuit topology of the flyback converter, etc., through the design and calculation we verify the feasibility of the scheme. The LED lighting switch power supply has the advantages of simple circuit, low cost, easy to control, and in accordance with the national standards LED production. The LED lighting switch power supply has wide application prospect and huge market space.