A 1.2-A buck-boost LED driver with on-chip error averaged senseFET-based current sensing technique

Sachin Rao, Qadeer Khan, Sarvesh Bang, Damian Swank, Arun Rao, William McIntyre, Pavan Kumar Hanumolu

Research output: Contribution to journalArticlepeer-review


This paper presents circuit techniques to improve the efficiency of high-current LED drivers. An error-averaged, senseFET-based current sensing technique is used to regulate the LED current accurately. Because the proposed scheme eliminates the series current-regulation element present in all conventional LED drivers, it greatly improves efficiency and reduces cost. The converter operates in three different operating modes, namely buck, buck-boost, and boost modes, and achieves high efficiency over the entire Li-Ion battery range (3-5.5 V). Fabricated in 0.5-μm CMOS process, the prototype occupies an active area of 5 mm}2. At 1.2-A LED current, the driver achieves an efficiency improvement of over 13% compared to current-regulation-element-based LED drivers. Measured LED current accuracy is better than 2.8% over the entire range of the battery and its standard deviation measured across seven devices is less than 1.6%. The peak efficiencies are 90.7% and 86% at 600- and 1200-mA currents, respectively.

Original languageEnglish (US)
Article number6007147
Pages (from-to)2772-2783
Number of pages12
JournalIEEE Journal of Solid-State Circuits
Issue number12
StatePublished - Dec 2011
Externally publishedYes


  • Buck-boost
  • LED driver
  • current sensing
  • dc-dc power converters
  • error averaging
  • flash light-emitting diode (LED)
  • high efficiency
  • lossless
  • on-chip
  • senseFET

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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