LED lamp high power factor driver design

With the uncontrolled consumption of energy resources, lighting products with energy-saving performance have been promoted by government organizations, and energy organizations in some countries have also issued relevant policies to subsidize lighting products that meet their standards. For example, commercial lighting products have a power factor greater than 0.9, and households greater than 0.7 are one of the mandatory requirements of the US Energy Star. Therefore, while paying attention to the high luminous efficiency and long life characteristics of LED lamps, it is particularly important to design LED drivers with high power factor and high performance while ensuring low component cost.

1 Overview of the development of LED lighting

Consumers' conversion from traditional lighting to LED lighting has been considered to be the trend of the times. Some articles have pointed out that LED lighting can save 80% energy compared to incandescent lamps, and its life span can be as long as 10 to 20 years. In addition, compared with compact energy-saving lamps, LED lamps do not contain environmentally harmful substances, such as mercury, mercury and other heavy metal substances, and there is no problem that the energy-saving lamps (CFLs) have a long warm-up time at startup, so the resources in the world are tight. In the big environment, balanced to the relationship between the environment and energy, the policy will also accelerate the promotion of LED lighting, because LED lighting is far superior to traditional lighting products in terms of lighting principle, energy saving and environmental protection, although in a short time The cost of LED lighting is very high. For example, the retail price of traditional 60W incandescent lamps is less than 1/10 of that of 7W LED lamps. Therefore, the current price of LED lamps for home users is still limited, but on the other hand, most of them are new. In the commercial lighting market under construction, such as hotels and shopping malls, LED lighting is used, and it is rare to see the shadow of traditional lighting.

This article will focus on the driving part of LED lighting, how to reduce the input current harmonics, and improve the input power factor. The energy problems in the lighting industry in developed countries have been highly valued. For example, the European energy standard EVP5 and the US Energy Star have clearly stated that the power factor PF of residential lighting drivers must be greater than 0.7, and the commercial lighting is greater than the mandatory requirement of 0.9.