Dynamic Output Resistance Optimization for Duty-cycle Control in Hybrid Capacitive LED Drivers

Juan C. Castellanos, Mert Turhan, Eugenio Cantatore

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

Abstract

This paper proposes a technique to optimize dynamically the efficiency of hybrid switched capacitor converters, while changing their output voltage/current. Pulse width modulation can be used to change the output current in LED drivers based on hybrid converters. However, changes in duty-cycle cause a reduction in efficiency due to the increasing output resistance of the associated switched capacitor converter. The proposed solution re-configures dynamically the ratio among the flying capacitors and the size of the switches in the power train to minimize the output resistance in different duty-cycle ranges. Transistor level simulations, using 180nm CMOS technology, show the benefits of this technique in a 3:1 Dickson step-down hybrid capacitive LED driver using three duty-cycle optimization regions. A better efficiency and flatter output resistance over a variable conversion ratio was achieved with up to 8% efficiency improvement in this case study, without increasing the area occupied by power switches and flying capacitors.

Original languageEnglish
Title of host publication2018 IEEE International Symposium on Circuits and Systems, ISCAS 2018 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers
Number of pages5
ISBN (Electronic)9781538648810
DOIs
Publication statusPublished - 26 Apr 2018
Event2018 IEEE International Symposium on Circuits and Systems, ISCAS 2018 - Florence Conference Center, Florence, Italy
Duration: 27 May 201830 May 2018
https://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=8334884

Conference

Conference2018 IEEE International Symposium on Circuits and Systems, ISCAS 2018
Abbreviated titleISCAS 2018
CountryItaly
CityFlorence
Period27/05/1830/05/18
Internet address

Keywords

  • Hybrid Switched Capacitor Converter
  • Integrated DC-DC converter
  • LED Driver

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