| It is a new hope of the 21st century lighting market by using LED lighting, especially the high-power white LED which is a new lighting products called "green light" light source, has a development potential. In urban road lighting systems with green energy-saving, safe and reliable LED lamp has become an important measure to construct economical society, and has a broad market space. Due to working in harsh outdoor environment, it is a high performance and reliability requirementsso to the driving power. At present, LED lamp drive power still exist such issues like low conversion efficiency, low power factor, low output current poor stability, the life can't match with LED, it has become a bottleneck to restricted LED lamp lighting devices to further promote application. Therefore, the development of high performance LED lamp drive power supply reliability has important practical value.This paper gives the background and research significance of high power LED drive power topics, reviews the development status of high power LED drive power, looks forward to the future trends, and briefly introduces the electrical characteristics of high power LED. On this basis, it proposes two levels of plan according to the LED the working characteristic and drive level standard which the former stage is PFC level, after class is DC/DC level. PFC grade adopts inductance Boost converter with current critical continuous mode, DC/DC grade adopts quasi resonant flyback mode. Due to the power factor correction technique with continuous mode,critical current peak control pattern has the simple control circuit, can realize zero voltage conduction, high power factor, it suitable for small and medium-sized power supply products. Therefore, this circuit adopts L6561 chip design a paragraph of active power factor correction circuit, applying 100W LED driving power, to reduce the harmonic interference, stable output voltage, make whole circuit the power factor of system up 0.99. And quasi resonant technology can reduce the MOSFET switching losses, thereby improving reliability. In addition, the softer switch improves the EMI characteristics of power supply, allow a designer to reduce the number of filters, thus reduce costs.This paper firstly deduces and designs the principle and main circuit parameters of power factor correction with critical continuous operation modes, and designs a detailed study based on the L6561 IC simplifies PFC control circuit. Secondly introduces in detail the theoretical basis and application of quasi resonant modes. Analyzes in detail the working principle and steady characteristics of flyback based on NCPl377. This apery briefly introduces the working principle and characteristics of the scheme, then analyzes a clamp and constant-volt/constant-current circuits based on AP431.Combining the scheme mentioned above, this paper made A wide range of input voltage (90 ~ 265Vac), output a 100W lighting LED switching power supply with 53V/1.8A, including the EMI filter circuits, power factor correction circuit based on the L6561, quasi resonant circuit with NCP1377, experimental results verify the feasibility of the proposed scheme. This LED drive power has simple circuit, low cost, easy control, and easier to compliance with relevant EMC standards etc, has a broad prospect of application.
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