A new design technique for sub-nanosecond delay and 200 V/ns power supply slew-tolerant floating voltage level shifters for GaN SMPS

Dawei Liu*, Simon Hollis, Bernard Stark

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

3 Citations (Scopus)
218 Downloads (Pure)

Abstract

Dual-output gate drivers for switched-mode power supplies require low-side reference signals to be shifted to the switch-node potential. With the move to ultra-fast switching GaN converters, there is a commercial need to achieve switch-node slew-rates exceeding 100 V/ns, however, reported level shifters do not simultaneously achieve the required power supply slew immunities and sub-ns propagation delays. This paper presents a novel design technique to achieve the first floating voltage level shifters that deliver slew-rate immunities above 100 V/ns and sub-ns delay in the same circuit. Step-by-step transistor-level design methods are presented. This technique is applied to improve a reported level shifter, and experimentally validated by fabricating this level shifter in a 180 nm high-voltage CMOS process. The final level shifter has zero static power consumption, and is shown to have a sub-nanosecond delay across the whole operating range, a 200 V/ns positive power-rail slew tolerance, and infinite negative slew tolerance. The measured propagation delay decreases from 722 ps with the floating ground at -1.5 V, to 532 ps for a floating ground of 45 V, and the power consumption is 30.3 pJ per transition at 45 V. It has a figure of merit of 0.06 ns/(μ mV), which is an 1.7 × improvement on the next best reported level shifter for this type of application.

Original languageEnglish
Article number8535039
Pages (from-to)1280-1290
Number of pages11
JournalIEEE Transactions on Circuits and Systems - I: Regular Papers
Volume66
Issue number3
Early online date14 Nov 2018
DOIs
Publication statusPublished - 1 Mar 2019

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Keywords

  • Area efficient
  • energy efficiency
  • floating voltage level shifter
  • GaN
  • gate driver
  • high speed
  • low power
  • slew tolerance

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