一种宽带高电源抑制比的低压差线性稳压器

A Wideband Low-Dropout Regulator with High Power Supply Rejection Ratio

介绍了一种宽带高电源抑制比的LDO结构。首先对传统采用运放结构的LDO难以满足PSR与运放增益带宽积的折中问题进行了分析,然后分析了采用OTA结构的LDO功耗较大的问题。为了解决上述问题,提出一种基于非对称OTA的LDO结构,功耗有了明显改善;同时在输出端支路加入了共源共栅管,进一步提升了该结构的PSR性能。采用SMIC0.18μm工艺完成设计与仿真,仿真结果表明在1MHz频率处PSR为-59.6dB,相比于传统LDO提升了19%,功耗仅为传统结构的三分之一。

This paper proposes a wideband LDO with high power supply rejection(PSR) ability.The PSRs of traditional LDO with operational amplifier(OPA) or operational transconductance amplifier(OTA) were firstly analyzed, revealing the dependence on the OPA’s gain band width(GBW) in the former, and the unavoidable high power consumption in the latter. A unsymmetrical OTA-based LDO has been proposed then, which draws significantly less power than its symmetrical OTA counterpart. Besides, cascode device has been added to the strong arm, improving the achievable PSR. The circuit has been designed and simulated on the SMIC180nm. The simulation results show that the PSR is-59.6dB at 1MHz, which is 19% higher than the traditional LDO, and the power consumption is only one-third of the traditional structure.