Challenge on compact size DC-DC buck converters with high-speed current sensor and on-chip inductors

• Published in: 2007 50th Midwest Symposium on Circuits and Systems pp. 670 - 673
• Main Authors: Shih-Min Chen, Chun-Yu Hsieh, Ke-Horng Chen
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.08.2007
• Subjects: Buck converters; Frequency modulation; Inductance; Inductors; Optical modulation; Pulse width modulation; Space vector pulse width modulation; Switches; Switching converters; Switching frequency
• ISBN: 1424411750; 9781424411757
• ISSN: 1548-3746
• DOI: 10.1109/MWSCAS.2007.4488668

This paper proposes a compact size DC-DC buck converter toward on-chip inductors and minimized external components. Multi-phase, high switching frequency and pseudo continuous conduction mode (PCCM) techniques achieve the possibility to implement on-chip inductors. The effective inductance is about 20nH. Due to high switching frequency above 20MHz, it is a challenge to have a highly accurate current sense for high performance of converters. Simulation results demonstrate that the accuracy of high-speed current sensor is about 95%. Besides, mode switch between pulse width modulation (PWM) and pulse frequency modulation (PFM) alleviates the limitation of high-speed current sensor in case of light load condition. Compact size design of converter is an advanced technique as a power module for system-on-chip (SOC) designs.