Research On High Efficient Boost LED Driver Circuit

Now the development of science and technology promotes the development of the technology of semiconductor materials, which leads to the application of white light in more and more occasions. At present, incandescent lamp stage is still the main source of illumination, but as light source incandescent lamp has many disadvantages:low intensity, low efficiency, high energy consumption and short service life, and because white LED has so many advantages such as:high brightness, high photoelectric efficiency, long service life, energy saving, environmental protection, white LED gradually replaces the incandescent lamp as a new generation of ideal lighting source, and has received the attention of many countries. Currently the main application areas of white LED are:one is the high brightness illumination occasion, such as indoor lighting, navigation lights, traffic lights, street lamps, automotive lighting and emergency exit light, etc; another is the low light situation, such as digital cameras, PAD, mobile phones and other portable small electronic equipment. Because the white LED light-emitting requires constant current, and switch converter has permanent current output, and high efficiency of switching, therefore, the dc switching converters are widely used in LED driver circuits. Most of today’s portable electronic devices are powered by lithium batteries, while lithium battery has low output voltage and wide changing range, which puts forward new requirements for dc switch converters, therefore, the research of dc switching converter has the vital significance for portable electronic devicesThis graduation design is mainly focused on the LED driver circuits with high efficiency high voltage gain, wide voltage input type. This article firstly introduces the LED driver research status at home and abroad, and kinds of DC - DC converters and their advantages and disadvantages are studied, and finally put forward the LED driver circuit to design in this paper. This paper puts up with a quadratic high-gain boost converter with switch capacitance, introduces switch capacitor on the basis of the traditional quadratic Boost converter, which furtherly improves the ability of the Boost converter, implements less duty ratio to obtain larger voltage gain, widens the input voltage range, eliminates the negative impact of the right half plane zero. Because the converter works under the conditions that duty ratio D is less than 0.5, which eliminates the slope compensation circuit, reduces the complexity of the control circuit. At the same time, the converter reduces voltage stress of the traditional quadratic Boost converter switch tube and diode, reduces the switch tube conduction loss and diode reverse recovery loss. In addition, the converter has continuous input current and small output voltage ripple. This paper analyzes the working principles and working characteristics of the converter, and a 12V/60V experimental prototype is set up on the basis of theoretical research, and the peak current control is adopted to conduct the dimming experiments, the experiment results show the validity of the theoretical analysis.