An error amplifier applied to white-light LED driver circuit was designed for the stability and reliability of the circuit. In combination with the working principle of DC/DC boost converter,a simple two-stage operational amplification circuit is adopted,which was designed by using CMOS technique of three-layer metal and the standard 0.5 μm two-layer polysilicon made by CSMC. The circuit is verified by Spectre simulation software. The open-loop gain of 54.8 7dB,common-mode rejection ratio of 70.98 dB,and power supply rejection ratio of 63.15 dB were achieved at power supply voltage of 2.5 V. Compared with the traditional design methods,this design can reduce the chip area,and meet the design specifications.%从电路的稳定性和可靠性出发,设计一款用于白光LED驱动电路中的误差放大器.结合DC/DC升压式变换器的工作原理,在无锡上华(CSMC)的标准0.5 μm两层多晶硅、三层金属CMOS工艺下,采用比较简单的两级运放电路.通过Spectre软件进行仿真验证,在2.5 V的电源电压下,得到开环增益为54.87 dB,共模抑制比为70.98 dB,电源电压抑制比为63.15 dB.该设计与传统的设计方法相比,减小了芯片的面积,同时基本达到设计指标.
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