TY - JOUR
T1 - Body bias voltage computations for process and temperature compensation
AU - Kumar, Sanjay V.
AU - Kim, Chris H.
AU - Sapatnekar, Sachin S.
PY - 2008/3
Y1 - 2008/3
N2 - With continued scaling into the sub-90-nm regime, the role of process, voltage, and temperature (PVT) variations on the performance of VLSI circuits has become extremely important. These variations can cause the delay and the leakage of the chip to vary significantly from their expected values, thereby affecting the yield. Circuit designers have proposed the use of threshold voltage modulation techniques to pull back the chip to the nominal operational region. One such scheme, known as adaptive body bias (ABB), has become extremely effective in ensuring optimal performance or leakage savings. Our work provides a means to efficiently compute the body bias voltages required for ensuring high performance operation in gigascale systems. We provide a computer-aided design (CAD) perspective for determining the exact amount of bias voltages that can compensate both temperature and process variations. Mathematical models for delay and leakage based on minimal tester measurements are built, and a nonlinear optimization problem is formulated to ensure highest frequency operation under all conditions, and thereby minimize the overall circuit leakage. Three different algorithms are presented and their accuracies and runtimes are compared. The algorithms have been applied to a wide range of process and temperature corners, for a 65- and 45-nm technology node-based process. A suitable implementation mechanism has also been outlined.
AB - With continued scaling into the sub-90-nm regime, the role of process, voltage, and temperature (PVT) variations on the performance of VLSI circuits has become extremely important. These variations can cause the delay and the leakage of the chip to vary significantly from their expected values, thereby affecting the yield. Circuit designers have proposed the use of threshold voltage modulation techniques to pull back the chip to the nominal operational region. One such scheme, known as adaptive body bias (ABB), has become extremely effective in ensuring optimal performance or leakage savings. Our work provides a means to efficiently compute the body bias voltages required for ensuring high performance operation in gigascale systems. We provide a computer-aided design (CAD) perspective for determining the exact amount of bias voltages that can compensate both temperature and process variations. Mathematical models for delay and leakage based on minimal tester measurements are built, and a nonlinear optimization problem is formulated to ensure highest frequency operation under all conditions, and thereby minimize the overall circuit leakage. Three different algorithms are presented and their accuracies and runtimes are compared. The algorithms have been applied to a wide range of process and temperature corners, for a 65- and 45-nm technology node-based process. A suitable implementation mechanism has also been outlined.
KW - Adaptive body bias (ABB)
KW - Circuit optimization
KW - Delay
KW - Leakage
KW - Process variations
KW - Temperature variations
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U2 - 10.1109/TVLSI.2007.912137
DO - 10.1109/TVLSI.2007.912137
M3 - Article
AN - SCOPUS:39749184704
SN - 1063-8210
VL - 16
SP - 249
EP - 262
JO - IEEE Transactions on Very Large Scale Integration (VLSI) Systems
JF - IEEE Transactions on Very Large Scale Integration (VLSI) Systems
IS - 3
M1 - 4444165
ER -