A systematic approach to designing a wide‐current range, MOS capacitor‐based switched‐capacitor DC‐DC converter with an augmenting LDO. (10th November 2017)

• Record Type: Journal Article
• Authors: Dogan, Hakan; El‐Sayed Mohammed, Shady A.
• Is Part Of: International journal of circuit theory and applications. Volume 46:Number 3(2018)
• Page Start: 468
• Page End: 482
• Publication Date: 2017-11-10
• Subjects: augmenting LDO -- frequency control loop -- interleaving -- switched‐capacitor converter efficiency -- switched‐capacitor DC‐DC converter; Electric circuit analysis -- Periodicals; 621.319205
• DOI: 10.1002/cta.2433
• Languages: English
• ISSNs: 0098-9886

Abstract

Summary: Switched‐capacitor DC‐DC converters (SC DC‐DC) are analyzed for loss sources, voltage regulation integrity, start‐up latency, and ripple size, while the trade‐offs between these metrics are derived. These analyses are used to design a SC DC‐DC that achieves high efficiency in a wide load current range. Four‐way interleaving was employed to reduce the output ripple and efficiency loss due to this ripple. The design can be reconfigured to achieve gains of 1/3 and 2/5 for inputs ranging between 1.4 and 3.6 V to generate output voltage range of 0.4 to 1.27 V and can supply peak load current of 22 mA. It uses thin‐oxide MOS capacitors for their high density and achieves 75.4% peak efficiency with an input frequency of 100 MHz and a load capacitor of 10 nF. An augmenting LDO that only regulates during sudden load transients helps the converter respond fast to these transients. The chip was implemented using a 65‐nm standard CMOS process. Abstract : A practical approach is employed to analyze switched‐capacitor DC‐DC converters (SC DC‐DC) for loss sources, voltage regulation integrity, start‐up latency, and ripple size, while the trade‐offs between these metrics are derived. These analyses are used to design a SC DC‐DC that achieves 75.4% peak efficiency in a wide load current range using core MOS capacitors. An augmenting LDO that only regulates during sudden load transients helps the converter respond fast to these transients.