Conventional power supply for micropower devices typically includes batteries, energy harvesting devices, or AC-DC converters with magnetic components (e.g., inductors or transformers), which results in bulky volume and high cost. This brief proposes a novel non-isolated 110/220 V input AC-DC converter without magnetic components, high voltage filter capacitors or rectifier circuits. The proposed converter has advantages of small volume, low cost and high reliability. The converter can interface the mains voltage (110/220 V AC) directly and convert it to a regulated DC voltage of 3.3/5 V for micropower devices. The working principles and theoretical analysis are presented in detail. Experimental results and comparative analysis verify the effectiveness of the proposed converter. The power supply solution achieves a maximum output power of 416 mW, resulting in a power density of 792 mW/cm3 based on PCB prototype, and the solution takes approximately one-third of commercial non-isolated product cost.