A Study of the Fully On-Chip Inductor Coils for 30 MHz Power Regulation Applications in Energy Harvesting, Sensor Networks, and IoT Scenarios

This letter looks into the performance of the on-silicon inductor coil with integrated buck dc–dc converters, made using a 180 nm bulk complementary metal-oxide semiconductor (CMOS) process. A parallel shunting structure with different metal layers was selected for its lower resistance and higher inductance at the specific low-power internet of things (IoT) scenario. The simulation results show that the fabricated inductors have stable values of more than 230 nH over the expected 1–50 MHz range. The proposed dc–dc converter's efficiency (2.4 to 1.2 V) reaches a maximum of 69.1% at 30 MHz for a 12.9 mA load. Our inductor coil achieved the highest inductance via the most straightforward CMOS technique without the additional expensive postprocessing technology. It pushes the boundary of power inductor integration with a dc–dc converter to a 30 MHz and 10 mW domain, thus exhibiting excellent potential for managing electricity in energy harvesting scenarios.