A compact 1–30 μH, 1–350 μF, 5–50 mΩ ESR compliant, 1.5% accurate 0.6 μm CMOS differential ΣΔ boost dc–dc converter

Abstract

Emerging high-end portable electronics demand on-chip integration of high-performance dc---dc power supplies not only to save pin count, printed circuit board (PCB) real estate, and the cost of off-chip components but also to better regulate the point of load (PoL). In the face of a widely variable LC filter, however, integrating the frequency-compensation circuit is difficult without sacrificing stability performance, which is why integrated controller ICs only cater to relatively narrow LC ranges. While ΣΔ control addresses this LC compliance issue in buck dc---dc converters with high equivalent series resistance (ESR) output capacitors, it is not clear how it applies to ΣΔ boost converters. To that end, this paper discusses, analyzes, and experimentally evaluates a prototyped 0.6 μm CMOS differential ΣΔ boost converter. Experimental results verified the switching supply was stable across 1---30 μH, 1---350 μF, and 5---50 m? of inductance, capacitance, and ESR while keeping output voltage variations in response to 0.1---0.8 A load and 2.7---4.2 V line changes to less than ±1.5%, peak efficiency at 95%, and switching frequency variation to less than 27%.