Research On Single Stage LED Driver Based On The Boost-Flyback Topology

The technology of LED lighting is promising. Compared with the traditional incandescent lamp, the LED lighting is more efficient and energy-saving. With the development of LED lighting technology, the LED driver attracts more attention. Nowadays, the LED drivers can be classified into two kinds:conventional two stage LED driver with PFC and single stage LED driver. The conventional drivers can attain high power factor, but the circuit is complex with high cost and big volume. While the single stage LED driver can also attain good performance by the optimal design of control method and topology.The first part of the paper introduces the current single stage driver. Since the input power is varying and the output power is constant, there must be an energy storing element. Generally, electrolytic capacitor is chosen as energy storing element. The voltage stress of electrolytic capacitor is a key parameter. At the same time, auxiliary circuit can also be chosen as energy storing element with multi-time control.Then the paper analyses the character of circuit based on Boost-Flyback. Primary control is chosen. The paper focuses on two methods:constant frequency and variable frequency. Multi-output is also discussed in the paper.Finally, the paper verifies the theoretical analysis by making a prototype with180Vac-264Vac input and32V/0.7A output. According to the experimental result, the paper also gives the modification of single stage LED driver.