An 80% peak efficiency, 0.84mW sleep power consumption, fully-integrated DC-DC converter with buck/LDO mode control

A fully-integrated step-down DC-DC converter with LDO mode to reduce the sleep power consumption and improve efficiency at light loads is presented. The converter can switch adaptively between the buck converter and the LDO mode by continuously sensing the load current. Besides, lossless current sense technique is implemented for the mode selection circuits. An improved LDO is also proposed to achieve good stability under various loads. The chip was implemented in 0.13µm CMOS technology. The measured peak efficiency reaches 80% at 90mA load, and efficiency at 10mA load increases by 22.6% compared with forced buck converter mode. Furthermore, the overall power consumption is reduced by 12X at the sleep mode, from 10mW without the hybrid mode to 0.84mW.

[1]  Zhiliang Hong,et al.  Improved on-chip components for integrated DC-DC converters in 0.13 µm CMOS , 2009, 2009 Proceedings of ESSCIRC.

[2]  Ramesh Harjani,et al.  Fully integrated on-chip DC-DC converter with a 450x output range , 2010, IEEE Custom Integrated Circuits Conference 2010.

[3]  Thomas H. Lee,et al.  A 3MHz Low-Voltage Buck Converter with Improved Light Load Efficiency , 2007, 2007 IEEE International Solid-State Circuits Conference. Digest of Technical Papers.

[4]  Vadim V. Ivanov.  Design Methodology and Circuit Techniques for Any-Load Stable LDOs with Instant Load Regulation and Low Noise , 2009 .

[5]  M. Steyaert,et al.  A fully-integrated 130nm CMOS DC-DC step-down converter, regulated by a constant on/off-time control system , 2008, ESSCIRC 2008 - 34th European Solid-State Circuits Conference.

[6]  R. Harjani,et al.  A High-Efficiency DC–DC Converter Using 2 nH Integrated Inductors , 2008, IEEE Journal of Solid-State Circuits.