A wire-embedded converter used for wearable devices

Abstract

This paper presents an integrated solution of flexible DC-DC converter by embedding a flexible polyimide printed circuit (FPC) board and an inductor made of flexible ferrite-polymer composite in a wire. The cooper in the wire is utilized as the winding to make the embedded inductor with flexible ferrite-polymer sheets. Different wire shapes of the inductor are simulated and compared to optimize the design. A step-up prototype is fabricated and corresponding tests are executed to verify the performance. The flexible wire-embedded converter can output 5V-1W with variational input, and achieve 70% efficiency.