Analysis of Unstable Operation in a Basic Delta Modulator for PWM Control

Hiroshi SHIMAZU  Toshimichi SAITO  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E88-A    No.8    pp.2200-2205
Publication Date: 2005/08/01
Online ISSN: 
DOI: 10.1093/ietfec/e88-a.8.2200
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Nonlinear Problems
pulse-width modulation,  delta modulators,  synchronization,  circle map,  bifurcation,  

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This paper studies dynamics of a delta modulator for PWM control. In order to analyze the circuit dynamics we derive a one-dimensional return map of switching time. The map is equivalent to a circle map in wide parameter region and its nonperiodic behavior corresponds to undesired asynchronous operation of the circuit. We then present a simple stabilization method of the system operations by means of periodic compulsory switching. The mechanism of the stabilization is considered from viewpoints of bifurcation. Using a simple test circuit, typical operations are confirmed experimentally.