The paper introduces the concept of power supply on chip (PwrSoC) which will enable the development of next generation, functionally integrated, power management platforms with applications in dc-dc conversion, gate drives, isolated power transmission and ultimately, high granularity on-chip, power management for mixed-signal, SOC chips. PwrSoC will integrate power passives with the power management IC, in a 3D stacked or monolithic form factor, thereby delivering the performance of a high efficiency dc-dc converter within the footprint of a low efficiency linear regulator. A central element of the PwrSoC concept is the fabrication of power micro-magnetics on silicon to deliver micro-inductors and micro-transformers. The paper details the magnetics on silicon process which combines thin film magnetic core technology with electroplated copper conductors. Measured data for micro-inductors show inductance operation up to 20MHz, footprints down to 0.5mm(2), efficiencies up to 93% and dc current carrying capability up to 600mA. Measurements on micro-transformers show voltage gain of approximately -1dB at between 10MHz and 30 MHz.