一种适用于LDO的新型斜坡软启动电路

A novel ramped soft-start circuit for Low-Dropout Regulator

摘要:

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。

Abstract:

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.