一种用于恒压AC-DC变换器的新型模拟指数波产生电路

A Novel Analog Exponential Wave Generator for Constant Voltage AC-DC Converter

提出了一种用于恒压AC-DC变换器的新型模拟指数波产生电路,并据此设计了一种受误差放大器输出动态调节幅值的可变指数波产生电路.该结构能够解决传统三角波恒压控制负载调节范围窄的问题,且相比于其他指数波电路,所提出的电路结构简单,可以有效节省版图面积,输出波形平滑,误差较小.对所提出的指数波产生电路输出电压进行了完整的分析和公式推导,并基于Nuvoton 0.35μm BCD工艺在Cadence Spectre仿真平台上验证了指数波产生电路的可行性和有效性.经仿真验证,轻载下的开关频率能够降低为三角波控制方式下的1/4,有效降低了轻载开关频率,且改进后指数波应用于恒压AC-DC变换器系统中负载调整率仅为0.542 mV/mA.

A novel analog exponential wave generator for constant voltage AC-DC converter is proposed.Based on this,a variable exponential wave generator is designed,which can dynamically adjust the amplitude according to the output of error amplifier.Compared with other exponential wave generator,the circuit structure of the proposed generator is simple,which can effectively save the layout area,the output waveform is smooth,and the error is small.The output voltage of the proposed exponential wave generator is analyzed and derived completely,and the feasibility and effectiveness of the exponential wave generator are verified on Cadence Spectre simulation platform based on Nuvoton 0.35μm BCD process.The simulation results show that the switching frequency under light load can be reduced to 1/4 of that of triangle wave control mode.The load regulation rate of the improved exponential wave applied to the constant voltage AC-DC converter system is only 0.542 mV/mA.