Design of Automatic Body Biasing System for Low Power VLSI Application

Dr.D. Venugopal, Dr.B. Jaishankar and R. Shyamala Banu

Body bias control is one of the most efficient means to reduce leakage power, adjust process variation, and apply performance boost. However, such control incurs a certain power overhead that has to be reduced, especially in ultra low-power systems. In order to exploit the advantages of body bias control while guaranteeing power efficiency, an on-chip control scheme is required. Conventionally, on-chip body bias control relies on the use of digital–analog converters. However, such analog circuits require a high power supply voltage and an additional power source, resulting in a considerable power overhead and an increased system cost. In this paper, an on-chip “Digitally assisted Automatic Body-bias Tuning” (DABT) scheme for ultra low-power systems is proposed and evaluated. The proposed scheme controls the body bias voltage so as to meet the timing constraints of a given target system. Since DABT is based on “Digitally assisted” circuitries, it can decrease the power supply voltage to near-threshold region and, therefore, a significant amount of power overhead can be reduced. According to the obtained evaluation results, the proposed system can enable 80% of leakage reduction while maintaining the frequency required meeting the timing constraints of the adopted target MIPS processor.

Volume 11 | Issue 1

Pages: 374-380