Bonding-wire triangular spiral inductor for on-chip switching power converters

Abstract

This work presents the first design and modelling of bonding-wire-based triangular spiral inductors (Fig. 1), targeting their application to on-chip switching power converters. It is demonstrated that the equilateral triangular shape compared to other polygonal shapes best balances the inductive density as well as the total Equivalent Series Resistance (ESR). Afterwards, a design procedure is presented in order to optimize the inductor design, in terms of ESR and occupied area reduction. Finally, finite-elements simulation results of an optimized design (27nH, 1 Ω) are presented to validate the proposed expressionsPeer ReviewedPostprint (published version

Unconventional applications of wire bonding create opportunities for microsystem integration

“…By placing a high permeability ring core over the metallization pattern, a transformer with a completely closed flux path was achieved (table 2(n)). In an interesting variation, authors of [72] have performed extensive modeling of spiral topology on-chip inductors formed from straight section wedge-wedge bonded wire-bond loops, with each of the three windings in a triangular arrangement. In this way, 27 nH inductors with 1 resistance were found to be feasible.…”

Fully-integrated inductive switched-mode DC-DC converters

“…As conducting wires have parasitic inductance, the bonding wires for IC packaging can be used for realizing an integrated inductor [14], [65], [66]. A commonly configured Π-structure bonding wire inductor is depicted in Figure 2.10(a).…”

“…with other loads may be similarly designed. By employing respective inductance models, bonding wire inductors of different shapes [65], [107] can be fitted into our proposed power loss model and evaluated. For sake of simplicity, the commonly employed Π-shaped bonding wire inductor (see Figure 2.10) is assumed and the inductance model based on Equation (2.6) is evaluated in the following analysis.…”