一种滞环恒流LED驱动电路的电流采样电路  

A Current Sensing Circuit for High-power LED Driver Using Hysteresis Current Control

作　　者：孙正旻[1,2] 陈后鹏[2] 王倩[2] 罗胜钦[1] 宋志棠[2] 

机构地区：[1]同济大学电子与信息工程学院,上海201804 [2]中国科学院上海微系统与信息技术研究所信息功能材料国家重点实验室,上海200050

出　　处：《电子科技》2012年第1期1-4,共4页Electronic Science and Technology

基　　金：国家集成电路重大专项基金资助项目(2009ZX02023-003);国家重点基础研究发展计划基金资助项目(2007CB935400;2010CB934300;2011CB309602;2011CB932800);国家自然科学基金资助项目(60906004;60906003;61006087;61076121);上海市科委基金资助项目(09QH1402600;1052nm07000)

摘　　要：针对滞环恒流大功率LED驱动芯片,提出一款高性能电流采样电路。该电路采用高压工艺,可承受最高达40 V的输入电压。通过分析滞环控制的特点,采用串联电阻采样技术,结合匹配电流源结构,在保证响应速度和采样精度的同时,降低了电路的复杂度。电路中加入输入电压补偿电路,进一步提高了恒流控制的精度。在Cadence下的仿真结果表明,电路可在800 kHz的频率下正常工作,采样精度达99.78%;当电压从15 V变化至35 V时平均负载电流误差为0.81%;输出电压范围为0～5 V。A high-performance current sensing circuit for the high-power LED driver using current control is proposed. It is a high-side current sensing circuit using high voltage process and can withstand up to a 40 V input voltage. By analyzing the characteristics of hysteresis control and using the series-sense resistor sampling technology and matched current source structure, the circuit reduces the complexity while ensuring the response speed and sam- piing precision. An input voltage compensation circuit is also added to improve the precision of current control. The simulation results in Cadence show that the circuit can work correctly when the operating frequency is 800 kHz. The current sensing accuracy can be up to 99.78%. When the input voltage changes from 15 V to 35 V, the average load current error is as small as 0. 81%. The output voltage ranges from 0 V to 5 V.

关 键 词：恒流控制 高压工艺 匹配电流源 电压补偿 

分 类 号：TN432[电子电信—微电子学与固体电子学]