一种新型的原边控制 LED 驱动电路研究与设计

摘要

为解决传统的副边控制方法存在控制电路复杂、成本高的问题，设计了一种应用于发光二极管（LED）照明的单级反激控制器中的原边控制电路。通过对原边反馈作输出电流估计，然后将估计值与基准电压作为误差放大器的输入来控制原边导通时间，从而实现平均输出电流的恒流控制。采用零电流开启技术，在电压谷底处打开功率管，减小了导通开关损耗。介绍了原边控制的相关原理和整体电路结构设计。设计采用0．5μm BCD 工艺，并通过 Hspice 仿真进行验证。结果表明，该电路成功实现了平均输出电流的恒流控制，驱动反激变换器工作在准谐振模式时有较高的转换效率。%In order to solve problems such as control circuit complexity and high cost in the traditional secondary side control way,this paper presents methods and circuits of a primary -side control for LED lighting.The output current is estimated by the primary side feedback,and the error amplifier input is combined with reference voltage to control the primary side turn -on time and achieve constant average output current control.The zero -current turn on technology is used by opening power tube at the valley of primary side voltage to reduce switch -on power dissipation.It introduces the theory of the primary side control and the design of whole circuit.The process of 0.5μm BCD craft is used and Hspice simulation is conducted for circuit test.The results of simulation show that the proposed circuit success-fully implements the constant average output current control and drives the flyback converter in quasi -resonant mode to achieve higher efficiency.