High-Power Factor Flyback Converter for an LED Driver with Ultra-Wide Output Voltage

In conventional AC-DC conversion, the bridge rectifier will convert the AC voltage to DC. However, the input current is not continuously flow through the circuit. Therefore, the input current shape will be deteriorated. Hence, the input power factor dropped. Furthermore, the conversion efficiency reduced and THD (Total harmonic distortion) level increased. This is due to the rectifier diodes which not in forward bias (turn ON) if the bulk capacitor voltage level more than peak input voltage. Additional power correction circuit will improve the input power factor. However, the number of components increase. On the other hand, some of the conventional power factor correction circuit increase the number of stages in power conversion. Moreover, ultra-wide output voltage for an LED driver is important because of the high-brightness LED’s efficiency is keep improving, hence, the lighting lamps are using LED to replace the traditional lighting lamps. Therefore, LED driver need a highly precise output current regulation because the colour and the brightness of the LED are based on the LED current level. This research is to evaluate the performance of high-power factor LED driver with ultra-wide output voltage with circuit simulation and experiment. This research is necessary because it is significant to the policies maker decision on the high efficiency electrical appliances. As for the example, the 80 plus standard set up by Ecos Consulting in year 2004 encourage the power supply manufacturer/ designer to achieves the standard. Therefore, the continuous development of new approaches to improve the power conversion efficiency is necessary. Furthermore, better electrical power management will lead to sustainable usage of energy. A lot of methods proposed to achieve high power factor such as AC-DC bridgeless topologies, synchronous converter, employing silicon carbide power diodes, improve the control strategies and etc. However, this study focuses to produce high power factor LED driver using flyback circuit topology. The Primary Side Regulation (PSR) for LED driver achieve international regulation like Energy Star for Solid State Lightning (SSL) product. PSR use primary side of power supply to control the output current with information to take away the sensing loss of output current and removing the output secondary feedback circuit. Due to this issue, without increasing the cost of SSL application, it able to fit the driver circuit inside a small-form factor lamps and reach the international requirement.