A novel Ramped Soft-Start(RSS) circuit for Low-Dropout Regulator(LDO) is presented.The RSS circuit generates dual asymmetric ramp signals instead of step signals for soft-starting LDO,eliminating the in-rush current at both the power-up moment and the enabling transient.The RSS circuit is fully integrated on-chip without any external components,which only takes 600 nA quiescent current.The regulator is implemented in 0.35 μm standard CMOS process,occupying 0.352 mm2 active area while the RSS consumes only 8.3% of the area of LDO.The measured line regulation is 2.7 mV/V and the measured load regulation is 0.064 mV/mA in the worst case.%提出了一种新型的应用于低压差线性稳压器(LDO)的斜坡软启动电路,其采用两路斜坡使能信号以及一路斜坡基准信号,消除了电源上电时产生的浪涌电流.该斜坡软启动电路已应用于一款LDO中,并采用0.35 μm CMOS工艺实现流片,其仅占LDO有效面积的8.3%,消耗电流仅600 nA.仿真以及测试结果显示,采用该软启动电路之后,LDO的上电浪涌电流得到有效抑制.LDO在最差情况下的线性调整率为2.7 mV/V,负载调整率为0.064 mV/mA.
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