Switched-Capacitor Filter Based Type-III Compensation for Voltage-Mode Control of Switched-Mode Buck Converters.

摘要

In this dissertation, we propose a novel technique for the voltage-mode control of switched-mode fixed-frequency Buck Converters using Switched-Capacitor Filters (SCF). The salient features of the analog sampled-data Type-III filter embodiment (using SCF) is a monolithic solution, automatic scalability of the filter's transfer function w.r.t. the Buck Converter's switching frequency, and moderate on-chip area and power consumption. While the proposed technique is aimed to explore a new design-space, it was observed that it can potentially combine the performance benefits of the conventional all-analog (power efficiency) and all-digital implementations (integration and programmability) of the Type-III compensation.;In our prototype, the proposed Type-III SCF-based voltage-mode controller Integrated Circuit (IC) is implemented in Texas Instruments' 0.36-microm BCD (Bipolar-CMOS-DMOS) technology. The IC is configured to control the Buck Converter for two programmable switching frequencies of 500 KHz and 1 MHz. The IC consumes 1.1 mA of static current from a 3.3 V power supply, and has an active-area of ∼ 0.65 mm2. The theoretical foundations have been validated by performing closed-loop load transient response and open-loop frequency response experiments; while operating the controller IC in closed-loop configuration with a Buck converter power stage.