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.

Automated summary

This letter examines the performance of on-silicon inductor coils with integrated buck dc-dc converters made using a 180 nm CMOS process. A parallel shunting structure with different metal layers was chosen for its lower resistance and higher inductance in low-power IoT scenarios. Simulation results demonstrate stable values of more than 230 nH for the fabricated inductors within the expected frequency range. The proposed dc-dc converter achieves an efficiency of 69.1% at 30 MHz for a 12.9 mA load, operating at voltage levels of 2.4 to 1.2 V. Our approach enables high-inductance integration without the need for costly postprocessing techniques, expanding the application of power inductor and dc-dc converter integration.