High Power Factor High-power Led Driver Control Chip Design

LED (Light Emitting Diode) is an energy-saving and environmental-friend green illumination source due to its long life-span, pollution-free. Great efforts have been put on research & development in LED and its application especially high power LED illumination application which tightly connected to our life, e.g. LED street lamp. ON the other hand, LED street lamp mainly powered by AC mains, high power factor is needed for high power LED driving to prevent the disturbing power harmonics.In this paper, fundamental working principle of LED driving circuit and Power factor corrections (PFC) technique is given. Based on those thesis a continuous current mode, average current PFC circuit based on boost switching regulation is designed and proposed, which can be used as PFC stage for high power LED driving circuit or single stage LED driving circuit with the help of Flyback topology. The input ac power voltage range is 90V~264V, switching frequency 100kHz, output power 100Watt, Output DC voltage 400V, Peak to peak DC ripple is 12V.When applied to a 110V ac input, its efficiency is up to 90% , Power Factor 0.95, which complies with its required design specifications.Based on the cooperated project with other company, a average current PFC controlling chip using unique modulation mode which suitable for continuous current is proposed in this paper, this circuit is designed and simulated on CSMC 0.5um 25V BCD process. Detailed circuit design and simulation on sub-circuits: Voltage reference-internal powers, current reference, modulated voltage, under voltage lock are done according to project's specification requirement. In the end, function of the whole circuit and performance under typical condition is verified and analyzed.