低压差双电容补偿高瞬态响应线性稳压器设计

Design of the Dual-Capacitor Compensation,Low Dropout Linear Regulator with a Transient-Enhanced Response

为适应现代电子产品对电源性能的较高要求,基于教学中应用的Spectre平台,采用源随器补偿方法设计了一种无片外电容的LDO稳压器。小补偿电容和大驱动能力的两级运放误差放大器,加快了电路的响应速度,提高了瞬态响应性能,并降低了输出电压波纹,从而增强了系统的稳定性。测试结果表明,电路的静态电流为30μA,工作输出电压为1.2 V,最大输出电流为100 mA,Vdrop为200 mV,相位裕度大于60°,在相应条件下的线性调整率SL、负载调整率So分别为0.05%(V/V),0.23%(V/A)。源随器补偿方法既可保证电路稳定工作,又能有效降低输出波纹和加快瞬态响应速度,已达到系统预期设计指标。

To meet the higher requirements of modern electronic products to the p ower performance,based on the Spectre platform of teaching,a off-chip capacito r LDO voltage regulator was presented with compensation used source follower and a small capacitor to block feedforward path.Error amplifier is a two stage amp lifier of high driving capability which can improve circuit speed and transient response,and reduce the output ripple.The test results show that the circuit w ith the static current of 30 μA,which owns the output voltage of 1.2 V,maxim um output current of 100 mA,and Vdrop for 200 mV,including the phase margin over 60°,the linear adjustment rate SLof 0.05%（V/V）and load adjustment rate So of 0.23%（V/A）under correspo nding conditions.The manager method with compensation used source follower,whi ch can guarantee circuit in good working order,and effectively reduce the outpu t ripple and speed up transient response,has been designed to achieve the system＇s anticipated targets.