A DLL-Based Body Bias Generator with Independent P-Well and N-Well Biasing for Minimum Energy Operation

Kentaro NAGAI
Hidetoshi ONODERA

IEICE TRANSACTIONS on Electronics   Vol.E104-C    No.10    pp.617-624
Publication Date: 2021/10/01
Publicized: 2021/04/20
Online ISSN: 1745-1353
DOI: 10.1587/transele.2020CTP0002
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuits and Their Application Technologies)
body bias generator,  minimum energy point tracking (MEPT),  adaptive body bias (ABB),  analog-assisted digital,  

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This paper proposes an area- and energy-efficient DLL-based body bias generator (BBG) for minimum energy operation that controls p-well and n-well bias independently. The BBG can minimize total energy consumption of target circuits under a skewed process condition between nMOSFETs and pMOSFETs. The proposed BBG is composed of digital cells compatible with cell-based design, which enables energy- and area-efficient implementation without additional supply voltages. A test circuit is implemented in a 65-nm FDSOI process. Measurement results using a 32-bit RISC processor on the same chip show that the proposed BBG can reduce energy consumption close to a minimum within a 3% energy loss. In this condition, energy and area overheads of the BBG are 0.2% and 0.12%, respectively.