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Current Sensing Circuit of MOSFET Switch for Boost Converter

부스터 변환기를 위한 MOSFET 스위치 전류 감지 회로

  • Min, Jun-Sik (Department of Semiconductor Engineering, Chungbuk National University) ;
  • No, Bo-Mi (Department of Semiconductor Engineering, Chungbuk National University) ;
  • Kim, Eui-Jin (Department of Semiconductor Engineering, Chungbuk National University) ;
  • Lee, Chan-Soo (Department of Semiconductor Engineering, Chungbuk National University) ;
  • Kim, Yeong-Seuk (Department of Semiconductor Engineering, Chungbuk National University)
  • 민준식 (충북대학교 반도체공학과) ;
  • 노보미 (충북대학교 반도체공학과) ;
  • 김의진 (충북대학교 반도체공학과) ;
  • 이찬수 (충북대학교 반도체공학과) ;
  • 김영석 (충북대학교 반도체공학과)
  • Received : 2010.07.14
  • Accepted : 2010.08.23
  • Published : 2010.09.01

Abstract

In this paper, a high voltage current sensing circuit for boost converter is designed and verified by Cadence SPECTRE simulations. The current mirror pair, power and sensing metal-oxide semiconductor field effect transistors (MOSFETs) with size ratio of K, is used in our on-chip current sensing circuit. Very low drain voltages of the current mirror pair should be matched to give accurate current sensing, so a folded-cascode opamp with a PMOS input pair is used in our design. A high voltage high side lateral-diffused MOS transistor (LDMOST) switch is used between the current sensing circuit and power MOSFET to protect the current sensing circuit from the high output voltage. Simulation results using 0.35 ${\mu}m$ BCD process show that current sensing is accurate and the pulse frequency modulation (PFM) boost converter using the proposed current sensing circuit satisfies with the specifications.

Keywords

Boost converter;LED driver;LDMOST;Current-sensing circuit

Acknowledgement

Supported by : 충북대학교

References

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