Design And Research Of Double Windings LED Driver

LED as a solid-state light source, its low-power, high-energy, long life and environmental friendly features and other characteristics become a new generation of green lighting source. Now LED will replace traditional lighting which is a universal trend. Thus as LED lighting will be the important part of the application. LED driver power supply should meet the dc drive, high efficiency, high reliability and other advantages base on the electrical characteristics of LED. Whereby the high-frequency switching power supply is becoming a hot spot of the LED driver technology. In this paper,we study the Double Windings LED drive module design and research.Purpose in view of the current LED market conditions, this article aims at the design of LED driver chip. The main research content first understand the object of study optical properties of LED, which determine the LED driver power supply design requirements.Chip module from the power supply circuit design of each topology. Firstly,this paper will analyse all kinds of topology structure output current equation, through the analysis of the topology structure and established the theory of wave by the general calculus to the ultimate goal of equation. Study the advantages and disadvantages of the constant current LED driver, which is simple RC structure, low cost, low reliability, which used in low-end LED market. Linear constant current drive circuit is not complicated, low cost, no flicker, and is conducive to driver and lamps are integratedbut its reliability needs to be improved, especially in the design ofsurges inrush. Non-isolated switching power supply with high efficiency in terms of widely used, commonly used in the DC-DC power supply module design.For safety consider, isolated switching power supply is widely used in furniture lighting. So this article focus on the research of isolated LED driver chip design.Isolated LED drive power applied to the high-end market, the design process often need to consider a variety of regulatory requirements. Traditional isolated LED driver power control complexity, high cost and the system component count and more, the reliability of the corresponding restrictions. This paper introduces a relatively streamlined flyback primary control LED driver power supply, eliminating the need for this type of power system secondary traditional power control, the feedback optocoupler, mainly through its ideological primary winding demagnetization secondary side feedback signal. The paper focuses on two-winding power LED driver chip, the program uses an integrated MOS parasitic capacitance charging and discharging the secondary transfer demagnetization signal to the primary side, it is possible to further simplify the system structure, greatly improving the reliability of the system. By constantly changing the feedback control signal causes a change in the structure, double winding drive chip design is the key research content of this paper.In this paper, the above ideas introduction of dual winding drive power LED driver system design and module design. The power system is mainly aimed at the single voltage input:180-264V output voltage:280mA 66-99V drive program. For circuit design, two-winding transformer design, design research dimming system startup, where dimming design variations occur by modifying the ADJ pin current change along with the system frequency to achieve frequency modulation dimming function. Chip-level design module introduces PWM comparator, each significant elements bandgap reference design, leading-edge blanking, under voltage protection, open circuit protection. The subsequent introduction of the control circuit control strategy using microarray secondary winding demagnetization signal area control. Proposed dimming module analog dimming and digital dimming design, which make the system more widely used.Eventually, the chip through 1um 40Vprocess flow sheet simulation and testing, follow-up to build the application system to verify the reasonableness of the LED driver chip design. Chip various parameters tested were able to achieve the metrics of system application.