基于反激式AC-DC开关电源中运放电路设计

Design of Operational Amplifier Circuit Based on Flyback AC-DC Switching Power Supply

现今时代是信息化的时代,信息技术的快速发展使得人们对于电子信息设备及产品的依赖性越来越大,这些设备及产品都离不开电源,其性能对电子产品的各项指标是否正常和其是否可以安全地工作起着重要作用。文章设计是采用CSMC 0.5μm工艺,基于Cadence平台设计的基于反激式AC-DC开关电源中两级运放电路,通过模拟仿真,最终使两级运放电路的低频开环增益大于75dB;输入共模电压1.2~4.8V;相位裕度约60°,比较稳定;转换速率大于10v/μs;输出摆幅为0.3~2.4V;共模抑制比大于70dB;电源抑制比大于70dB。

Today's era is the era of information,the rapid development of information technology makes people more and more dependent on electronic information equipment and products,these devices and products are inseparable from the power supply.Its performance plays an important role in whether the indicators of electronic products are normal and whether they can work safely.This design adopts CSMC 0.5μm process and based on Cadence platform,the two-stage operational amplifier circuit based on flyback AC-DC switching power supply is designed.Through simulation,the low-frequency open-loop gain of the final two-stage operational amplifier circuit is more than 75dB,the input common-mode voltage is 1.2~4.8V,the phase margin is about 60°,which is relatively stable,the conversion rate is greater than 10v/μs,the output swing is 0.3~2.4V,the common-mode rejection ratio is greater than 70dB,and the power supply rejection ratio is greater than 70dB.