High-Efficiency Drive Circuit Research With Electrically Isolation And Its Application In Led Lights

LED lighting has the advantages of environmental, high-efficiency, energy-saving, safe and reliable over other lighting devices. This paper based on the theory research of utility power white LED lighting drive circuits, analyzes the test data from experimental circuits, including the following aspects:Firstly, state is conducted from the topologies of utility power AC-DC-DC converters, which are generally classified into two categories:non-electrically isolated drive circuit and electrically isolated drive circuit. Then, many ways are introduced to improve the circuit efficiency, boost the power factor, optimize overall layout of the LED light and load arrangement based on various topologies.Secondly, several white LED lighting drive circuits with different topologies, power grades and applications are recommended, which are designed by our laboratory. After repeated improvements and strict tests, there is one non-electrically isolated T8LED lighting tube that has got Singapore TUV PSB Quality Authentication; one electrically isolated white LED driver satisfied the requirements of TUV PSB and Energy Star Authentication.What’s more, many self-made high-frequency switch-mode power transformers made of various ferrite cores during the research of electrically isolated white LED lighting drivers, are described. Formula derivation and constantly amendments of magnetic core gap, structure adjustment of multi-winding distribution and ratio are conducted in order to improve electromagnetic conversion efficiency, change magnetic flux coupling co-efficiency, increase transmission power and optimize the match between the electrically isolated transformer and peripheral drive circuit. By this way, the power utilization efficiency of LED lights, performance and life all become better.Finally, analysis is also conducted to the power factor correction module design strategies of commercialized LED lights and function comparison is made between passive PFC and active PFC, which is supported by circuit experiments.