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摘要
In order to reduce the cost and volume of small-medium power ac-dc light-emitting diode (LED) lighting systems, single-stage LED drivers are often used to drive LEDs with constant current. In this paper, a single-stage isolated high-power factor ac-dc LED driver is proposed and analyzed in detail, which is composed of a buck-boost power factor correction unit operating in discontinuous conduction mode and an isolated dc/dc unit with a voltage doubler rectifier, and the two units are integrated together by sharing the same power switch. Very high input power factor is achieved since the PFC unit operates with almost fixed duty ratio during half period of the utility line voltage. Since a voltage doubler rectifier is included in the isolated dc/dc unit, magnetic core size of the transformer and voltage stress of the secondary side diodes are reduced remarkably. First, the operating principle and performance of the LED driver are analyzed. Then, the main parameters are quantitatively calculated out in detail. Finally, a comparative analysis is presented and a 120W experimental prototype with 1 A output current is built according to the calculated parameters and the experimental results are presented to verify the correctness of the theoretical analysis and parameter design.
- 出版日期2017-7
- 单位重庆大学
