A Forward/Reverse Body Bias Generator with Wide Supply-Range down to Threshold Voltage

Norihiro KAMAE  Akira TSUCHIYA  Hidetoshi ONODERA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E98-C   No.6   pp.504-511
Publication Date: 2015/06/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E98.C.504
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuits and Related SoC Integration Technologies)
Category: 
Keyword: 
body bias generator,  dynamic voltage frequency scaling,  low supply voltage,  analog-assisted digital,  switched-capacitor circuits,  

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Summary: 
A forward/reverse body bias generator (BBG) which operates under wide supply-range is proposed. Fine-grained body biasing (FGBB) is effective to reduce variability and increase energy efficiency on digital LSIs. Since FGBB requires a number of BBGs to be implemented, simple design is preferred. We propose a BBG with charge pumps for reverse body bias and the BBG operates under wide supply-range from 0.5 V to 1.2 V. Layout of the BBG was designed in a cell-based flow with an AES core and fabricated in a 65 nm CMOS process. Area of the AES core is 0.22 mm2 and area overhead of the BBG is 2.3%. Demonstration of the AES core shows a successful operation with the supply voltage from 0.5 V to 1.2 V which enables the reduction of power dissipation, for example, of 17% at 400 MHz operation.