A 50 nW-to-10 mW Output Power Tri-Mode Digital Buck Converter With Self-Tracking Zero Current Detection for Photovoltaic Energy Harvesting

作者：Chen Po Hung^*; Wu Chung Shiang; Lin Kai Chun

来源：IEEE Journal of Solid-State Circuits, 2016, 51(2): 523-532.

DOI：10.1109/JSSC.2015.2506685

• Asynchronous mode (AM)
• buck converter
• digital pulsewidth modulation (DPWM)
• digital zero current detection
• pulse-frequency modulation (PFM)
• tri-mode

This paper presents a tri-mode digital buck converter in 0.18-mu m CMOS technology for photovoltaic energy harvesting. The on-chip gate-boosted digital pulsewidth modulation (DPWM) improves the conversion efficiency at heavy load conditions. Pulse-frequency modulation (PFM) along with digital self-tracking zero current detection is proposed to avoid reverse current at light load. The asynchronous mode (AM) operation further reduces the controller loss and improves the conversion efficiency at ultra-light load conditions. By applying DPWM, PFM, and AM at different load conditions, the proposed converter provides a maximum conversion efficiency of 92% with output power ranging from 50 nW to 10 mW. In addition, the proposed buck converter achieves more than 70% efficiency from 400 nW to 10 mW output power.

• 出版日期2016-2