An ultra-low-power adaptive-body-bias control for subthreshold circuits

Lowering power consumption extends battery lifetime and reduces the battery size that determines the dimension of distributed sensor nodes. One of the effective low-power solutions is using subthreshold circuits. However, subthreshold circuits suffer from process variations that question the robustness in the practical applications. Adaptive designs are necessary although the power overhead must be seriously constrained. Accordingly, this work presents an ultra-low-power adaptive-body-bias method, of which the additional power consumption is at a leakage level. The proposed circuits can be operated in dynamic voltage scaling with multiple configurations to simplify the implementation of power management. The measurement results of the test chips showed effective compensation for the process variations. The characteristics of the subthreshold circuits were simultaneously enhanced.