Construction of Chaotic Circuit for Chaotic Switching of LED Driver

Abstract

This backbone of this project is to construct a chaotic circuit to generate a chaotic signal that can be fed to a normal PWM LED driver in order to reduce the electromagnetic interference (EMI). Invented in 1976, pulse width modulation (PWM) has become widely used in different electronic devices like LED drivers. However, the drivers have a great potential that it will cause interference to the system of electronic appliances on the condition that their current and voltage change rapidly. Studies shows that one of the ways to reduce EMI is using spreadspectrum technique. Being able to generate continuous spectrum and pseudo- randomness, a chaotic circuit was constructed to applied on LED driver to reduce the presence of EMI. In the beginning of the project, different types of chaotic circuit were reviewed. Chau’s circuit was selected was then chosen due to its simplicity with good performance. Some adjustments were made in order to make it perform better. Different testing was undergone after the circuit had been built for finding results like the waveform of the voltage at different state, FFT of the chaotic signal, etc. An exploration into how to turn the chaotic signal into a PWM signal was carried out so that it can be linked into a normal LED driver driven by PWM. An attempt was made in building a switching circuit to execute the theoretical exploration. The possible outcome from the circuit will also be discussed.