One embodiment relates to an apparatus that includes at least one circuit block and a voltage source configured to supply a first voltage to the at least one circuit block. The apparatus also includes a power delivery unit configured to be selectively activated based on a whether a quantity of power is to be delivered from the power delivery unit to the circuit block. A control unit is configured to, upon a change in power consumption of the at least one circuit block, activate the auxiliary power delivery unit to deliver the quantity of power to the circuit block. The auxiliary power delivery unit can quickly supply large currents since it does not necessarily rely on slow control loops using voltage sensing. Rather, the auxiliary power delivery unit often delivers pre-calculated current profiles to respond to the timing characteristic of the change of power consumption and of the voltage regulator.