An on-die ultra-low voltage DC-DC step-up converter with voltage doubling LC-tank

Jayaweera H. M. P. C., Pathirana W. P. M. R., Muhtaroglu A.

JOURNAL OF MICROMECHANICS AND MICROENGINEERING, vol.26, no.12, 2016 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 26 Issue: 12
  • Publication Date: 2016
  • Doi Number: 10.1088/0960-1317/26/12/124010
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: charge pump, step-up converter, center-tap inductor, ultra-low voltage, LC-tank, on-die converter, DC-DC converter, BOOST CONVERTER, CHARGE PUMP, ENERGY, CIRCUITS
  • Middle East Technical University Affiliated: Yes


In this paper we report the design, characterization and verification of a novel on-die ultra-low voltage DC-DC converter circuit for energy harvester applications in 0.18 mu m complementary metal oxide semiconductor (CMOS) technology. The circuit self-starts, does not use off-chip components, and is thus suitable for use in highly integrated low cost systems. The first version of the design has a five-stage charge-pump stimulated by an oscillator with two center-tap inductors. It is validated on a test chip that this converter can boost 0.25 V-1.7 V for a 60 k Omega load with 15.5% maximum efficiency. The center-tap implementation leads to a 38% area reduction compared to the conventional four planar inductors. The proposed second version of the DC-DC design has a modified LC-tank with center-tap and planar hybrid inductors, which leads to a simulated step up from 0.2 V input to 1.65 V output for a 45 k Omega load with 35% maximum efficiency. The new boost implementation is hence expected to improve both power efficiency and output power capacity significantly compared to the first design, at a cost of a 31% layout area growth. The second revision in addition provides a 15% chip area reduction compared to the conventional four planar-inductor approach.