Increasing LTCC inductance density by using inverse coupling technique and multi-permeability structure

Abstract

Inductor size is one of the biggest challenges to reduce the size of the portable electronic devices. Several methods are presented for reducing inductor’s size, among which LTCC has a specific significance in low power converters. Given the fact that it does not need any additional control circuits and also by considering its structure and constituent materials, the value of this inductor and its efficiency increases. This paper investigates LTCC inductor with the inverse coupling method in form of a multi-permeability structure. First, the inverse coupling inductor is considered in vertical and lateral flux patterns in the single permeability state and then, these inductors’ behaviors are considered in a multi-permeability structure by optimizing inductor’s core. Ultimately, a new structure in multi-permeability lateral flux inductor is presented which leads to increasing inductance density that is more phenomenal in low currents. Then, the behavior of the proposed inductor is investigated in a buck converter with 1.5 MHz switching frequency. It is observed that power density increases up to 735 (w/in3). Performance accuracy of mentioned inductor is confirmed by simulation in MATLAB and FEA2D FLUX.

Keywords

• LTCC| multi-permeability| inverse coupling| hybrid inductor