Fully-Integrated Two-Cell Interleaved Switched-Capacitor Step-up Voltage Converter For Battery-less Implantable Systems

Document Type : Original Article

Authors

1 Dept. of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, Iran

2 Dept. of Electrical and Computer Engineering, Bushehr Branch, Islamic Azad University, Bushehr, Iran

3 Faculty of Science and technology , Islamic Azad University

Abstract

A fully-integrated self-start-up low-voltage battery-less switched-capacitor step-up voltage converter is proposed that can operate in sub-threshold voltages. For this purpose, a two-branch charge pump is designed with cross-coupled voltage doubler structure. For proper operation, an anti-phase clock generator circuit is designed to operate at the same supply voltage. Body biasing technique is applied to the MOSFET transistors so that the circuit can operate in sub-threshold voltages. The proposed interleaved regulation technique improve the output voltage and current ripple, as well as the load regulation and transient response. The four-stage two-cell interleave charge pump circuit provide the output voltage of 1.43 and 1.95V under 300 and 400mV supply voltage with the pumping efficiency of 96.3% and 97.2%, and CP power efficiency of 93.3% and 95.1%, respectively. Post-layout simulation in 0.18µm CMOS technology shows a 24µs ramp-up time and 0.24% output voltage ripple at 20MHz switching frequency and 1pF load capacitance. The chip area of the proposed circuit is 0.012mm2 while the CP consuming only 21.4nW.

Keywords

Main Subjects

Electronics Industries
Volume 11, Issue 3 - Serial Number 43
September 2020
Pages 39-52

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History

  • Receive Date: 17 April 2019
  • Revise Date: 01 May 2020
  • Accept Date: 06 September 2020
  • First Publish Date: 22 September 2020

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