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Design of Low Dropout Regulator using self-cascode structure

셀프-캐스코드 구조를 적용한 LDO 레귤레이터 설계

  • Choi, Seong-Yeol (Department of Semiconductor Engineering, Chungbuk National University) ;
  • Kim, Yeong-Seuk (Department of Semiconductor Engineering, Chungbuk National University)
  • Received : 2018.03.26
  • Accepted : 2018.06.14
  • Published : 2018.07.31

Abstract

This paper proposes a low-dropout voltage regulator(LDO) using self-cascode structure. The self-cascode structure was optimized by adjusting the channel length of the source-side MOSFET and applying a forward voltage to the body of the drain-side MOSFET. The self-cascode of the input differential stage of the error amplifier is optimized to give higher transconductance, but the self-cascode of the output stage is optimized to give higher output resistance, The proposed LDO using self-cascode structure was designed by a $0.18{\mu}m$ CMOS technology and simulated using SPECTRE. The load regulation of the proposed LDO regulator was 0.03V/A, whereas that of the conventional LDO was 0.29V/A. The line regulation of the proposed LDO regulator was 2.23mV/V, which is approximately three times improvement compared to that of the conventional LDO. The transient response of the proposed LDO regulator was 625ns, which is 346ns faster than that of the conventional LDO.

본 논문에서는 셀프-캐스코드 구조를 이용한 LDO 레귤레이터를 제안하였다. 셀프-캐스코드 구조의 소스 측 MOSFET의 채널 길이를 조절하고, 드레인 측 MOSFET의 바디에 순방향 전압을 인가함으로써 최적화하였다. 오차 증폭기 입력 차동단의 셀프-캐스코드 구조는 높은 트랜스컨덕턴스를 가지도록, 출력단은 높은 출력 저항을 가지도록 최적화하였다. 제안 된 LDO 레귤레이터는 $0.18{\mu}m$ CMOS 공정을 사용하였고, SPECTERE를 이용하여 시뮬레이션 되었다. 제안 된 셀프-캐스코드 구조를 이용한 LDO 레귤레이터의 로드 레귤레이션은 0.03V/A로 기존 LDO의 0.29V/A보다 급격하게 개선되었다. 라인 레귤레이션은 2.23mV/V로 기존 회로보다 약 3배 향상되었다. 안정화 속도는 625ns로 기존 회로보다 346ns 개선되었다.

Keywords

References

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