Effectiveness of Weak-Inversion Current Reduction

The effectiveness of energy reduction techniques is best observed when charge or energy delivered by the power supply source is considered, instead of comparing static leakage currents or power in standby and active periods (see figure 2.3 for definitions). Time aspects need to be taken into account. Addition of circuitry enabling weak-inversion-current reduction brings extra power dissipation with it. Therefore, the effectiveness and usefulness of leakage-power reduction techniques for specific applications is best determined in terms of the break-even standby time. The break-even standby time indicates a minimum standby time, required before power reduction techniques provide for any gains. In section 7.1 the impact weak-inversion current-reduction techniques have in general on break-even standby times is discussed. Section 7.2 considers the effectiveness of three specific (practical and theoretical) weak-inversion current reduction techniques.