A power delivery network (PDN) including a battery, a set of regulators for generating supply voltages, and an integrated circuit (IC) including power rails configured to receive the supply voltages. The IC further includes an IC chip having a set of cores. The power rails includes a larger rail configured to provide a full range of currents, and the other smaller power rails each configured to provide lower range of currents. The IC includes multiplexers having first inputs coupled respectively to the smaller rails, second inputs coupled to the larger rail, and outputs coupled to the cores. When the smaller rail is able to supply the current needed by a core, the multiplexer is configured to couple the smaller rail to the core. When the smaller rail cannot supply the current needed by the core, the multiplexer is configured to couple the larger rail to the core.