A high power efficiency class AB switched-opamp for low voltage low power sigma-delta modulators

Hanging Wang, Jian Xu, Xiaobo Wu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

Two-stage Class-A switched-opamp (SO) is the most popular module in previous low voltage low power SO sigma-delta modulators (SDM). The SO saves about 30%∼40% of the total power since its output stage is just turned off at the integrating phase. To further increase efficiency a novel high power efficiency class AB current mirror SO is proposed in this paper. By turning off the entire SO together with its common mode feedback (CMFB) circuit, the power consumption of the SO can be reduced by 50%. A Class-AB load-compensated opamp version improves the power efficiency further. The proposed SO was fabricated in a 0.35μm TSMC CMOS standard process and achieved a DC gain of 62.7dB, a GBW of 4.39MHz and a slew rate of 1.2V/μs when the load capacitor is 10pF. The effective power consumption including the CMFB circuit is 6.6μW under 1.5V supply voltage. The simulation results showed that the proposed SO can be applied to low power low voltage SDM with a sampling frequency of less than 0.5MHz.

Original languageEnglish (US)
Title of host publication2009 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2009
Pages429-432
Number of pages4
DOIs
StatePublished - Dec 1 2009
Event2009 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2009 - Xi'an, China
Duration: Dec 25 2009Dec 27 2009

Publication series

Name2009 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2009

Other

Other2009 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2009
CountryChina
CityXi'an
Period12/25/0912/27/09

Keywords

  • Common mode feedback circuit (CMFB)
  • Sigma-delta modulator (SDM)
  • Switched opamp (SO)

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