Fully-Integrated High-Conversion-Ratio Dual-Output Voltage Boost Converter With MPPT for Low-Voltage Energy Harvesting

Abstract

This paper proposes a fully-integrated high-conversion-ratio dual-output voltage boost converter (VBC) with maximum power point tracking (MPPT) circuits for low-voltage energy harvesting. The VBC consists of two voltage generators that generate V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OUT1</sub> and V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OUT2</sub> . V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OUT1</sub> and V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OUT2</sub> are three and nine times higher than the harvester's output V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">IN</sub> , respectively. V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OUT1</sub> is used as a supply voltage for on-chip application circuits while V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OUT2</sub> is used as the charging voltage for a Li-ion secondary battery. The VBC achieves a high voltage conversion ratio (max. × 9) and a high power conversion efficiency. The MPPT circuits control the operating frequencies of the CPs to extract maximum power at each output. The measurement results demonstrated that the circuit converted a 0.59 V input to a 1.41 V output with 75.8% efficiency when the output powers of V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OUT1</sub> and V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OUT2</sub> were 396 and 0 μW, respectively, and a 0.62 V input to a 4.54 V output with 49.1% efficiency when the output powers were 0 and 114 μW, respectively.