그라운드 제어 방법을 이용한 Low Dropout Regulator의 설계와 분석

학위논문 (석사)-- 서울대학교 대학원 : 공과대학 전기·정보공학부, 2018. 8. 정덕균.With a continuously high demand for portable electronic devices and System-on-Chip (SoC) devices in market, which uses Li-ion batteries, design of a low dropout regulator (LDO) with a high power supply rejection (PSR) is crucial to reject deterministic output ripple of a DC-DC converter, which is in between the battery output and a low dropout regulator, at the switching frequencies. In response, this thesis presents a low dropout regulator with high unity gain bandwidth using ground regulation technique. The proposed low dropout regulator targets to have wide loop gain unity gain bandwidth to have the power supply rejection to be high even at high frequency (~ 1 MHz). Because wide bandwidth implies high quiescent current for an LDO, ground regulation technique with a reference change has been applied to reduce the current dissipation. The proposed low dropout regulator is intended to be fabricated in 65 nm CMOS technology, achieves power supply rejection of -50.5 dB at 1 MHz, and dissipates quiescent current of 212 μA, which is a number that is reduced by 3 times from its complementary conventional LDO design with similar LDO performance. Keywords : Low Dropout Regulator (LDO), Portable Electronic Devices, System-on-Chip (SoC), Ground Regulation, Power Supply Rejection (PSR), Quiescent Current Student Number : 2016-22765Table of Contents Chapter 1. Introduction 1 1.1 Backgrounds 1 1.2 Motivation 2 1.3 Thesis Organization 3 Chapter 2. Basics of Low Dropout Regulator 4 2.1 Architecture of Low Dropout Regulator 4 2.2 Specifications of Low Dropout Regulator 6 2.3 Different Types of Low Dropout Regulator 9 Chapter 3. Design of Ground Regulating LDO 16 3.1 Analysis on Reference Change 16 3.2 Frequency Response Analysis 19 3.3 Proposed Architecture 20 3.4 Circuit Implementation 23 3.5 Comparison of a Supply Regulating LDO and Ground Regulating LDO 27 3.6 Load Transient Analysis 29 3.7 Level Shifter 33 Chapter 4. Simulation Results 34 4.1 Layout 34 4.2 Alternating Current Simulations 35 4.3 Transient Simulations 39 4.4 Performance Summary 45 Chapter 5. Conclusion 47 Bibliography 48 Abstract in Korean 53Maste