【摘要】 为了解决LED恒流驱动输出电流不稳的问题,提出采用双反馈环路的通道结构。在此基础上,设计了采用分段模式的快速启动电路,可极大地提升通道的开启速度。基于0.25μmBCD工艺,完成HSPICE仿真。结果显示,该系统的外环路增益为83dB,相位裕度为80o,通道间电流互不影响。当电流在5～45mA范围内变化时,快速启动电路正常工作,通道的开启时间仅为4ns,开启速度较传统结构有显著提升。该输出通道已成功应用于LED恒流驱动中。更多还原

【Abstract】 To solve the problem of output current instability in LED constant-current driver,a channel structure with dual feedback loop was proposed.Based on the structure,a fast startup circuit using segmentation mode was designed to enhance turn-on speed of the channel.The circuit was simulated with HSPICE based on 0.25 μm BCD process.Results showed that the system had an outer loop gain of 83 dB,and a phase margin of 80o with no interaction of currents between channels.The fast startup circuit operated properly when channel current varied from 5 mA to 45 mA.The turn-on time of the channel was only 4 ns,which was a significant improvement,compared to the traditional structure.The proposed output channel has been applied to LED constant-current driver successfully.更多还原