Techniques are provided that can extend the efficiency of a switching regulator further into the low current region by making use of the available knowledge on predictable load variations and voltage ripple tolerance across different states, providing improved efficiency and reducing total current consumption. The load current requirement in low power states is provided using switch mode rather than linear regulation, the switch mode operation being controlled by a mode dependent control circuit so as to minimize the energy cost of the switching operation in each mode and thus obtain improved efficiency from the power source.