A self-adjusting scheme to determine the optimum RBB by monitoring leakage currents

Reverse body biasing (RBB) is often used to reduce the leakage power of a device. However, recent research has shown that if this applied RBB is too high, the leakage power can actually increase due to the contribution of band-to-band tunneling (BTBT) currents. Hence, there exists an optimal RBB value at which the leakage is minimum. This optimum point can vary with temperature and process variations. In this paper we show that it is desirable to operate at the optimal RBB point which minimizes total leakage. We present a scheme that monitors the total leakage current (the sum of the sub-threshold, BTBT and gate leakage) of an IC with a representative leaking device and, using this monitored value, automatically finds the optimum RBB value across temperature and process corners, using a self-adjusting circuit. Our approach has a modest placed-and-routed area utilization, and a low power consumption.