一种用于开关电源的高性能误差放大器设计

摘要

设计了一种用于开关电源的高性能误差放大器。该误差放大器的核心是一个三级放大结构，其中第二级放大是基于传统折叠式共源共栅放大器，增加了“交叉耦合结构”，以此实现高增益设计。另外，高低电平钳位设计增强了误差放大器在不同工作条件下的性能。为提高电路在开关电源中的实用性，还设计了补偿选择电路。设计的误差放大器采用TSMC 0.35µm BCD工艺流片，电路达到设计要求，性能良好，在46XX电源模块中得到实际应用。%A high performance error amplifier for switching power supply was presented. Its core design is a three stage amplifier. In order to get high gain, we design a “cross coupling structure” for the second stage amplifier which is based on traditional folding cascade. In addition, the high-low level clamp design can enhance the amplifier’s working performance. To improve the EA’s practicality in field of switching power supply, a compensation selecting circuit was designed. The EA in this paper has been chipped by TSMC 0.35 µm BCD process and get a high performance. Also it has been applied in 46XX power supply.