PCB transformers are desirable for future high density power converter applications due to their manufacturing process which reduces transformer parasitic variation, labor, and system cost. Little is known about their thermal performance in high power applications which limits their commercial adoption. This paper analyzes flexible PCB technology with its naturally thin dielectric as a way to enable high density, high current PCB transformers with acceptable thermal margins. 10-layer, 1 MHz, 1.7 kW flex and FR4 PCB transformers were constructed and flex PCB showed ~20 C peak temperature reduction compared to its FR4 counterpart. This paper also investigates via current sharing strategies for high frequency, high amperage PCB transformers which balance current sharing and total loss. Using the proposed strategies, via utilization is increased from 50% to 100%.
