Title :
Application of spread spectrum for EMI reduction in class D amplifier
Author :
Wang, Haishi ; Zhang, Bo ; Sun, Jiang ; Wang, Rui
Author_Institution :
State key Lab. of Electron. Thin Films & Integrated Devices, Univ. of Electron. Sci. & Technol. of China, Chengdu, China
Abstract :
A spread spectrum technique and apparatus for reducing electromagnetic interference (EMI) in class D amplifier are introduced. The technique utilizes very simple hardware, where the switching frequency of a class D amplifier is dynamically varied from 1 to 1.22 MHz. This is achieved by changing the charging current of an oscillator in a random fashion, through 6 switches that are controlled by 6 random digital signals. Compared to fixed frequency operation, the spectrum of a switching signal was greatly flattened and a reduction of 6 dB in the EMI without efficiency and performance degradations was obtained.
Keywords :
amplifiers; electromagnetic interference; interference suppression; oscillators; spread spectrum communication; EMI reduction; class D amplifier; electromagnetic interference; frequency 1 MHz to 1.22 MHz; noise figure 6 dB; oscillator charging current; performance degradations; random digital signals; spread spectrum; switching frequency; Electromagnetic interference; Frequency modulation; Oscillators; Switches; Time frequency analysis; Transistors;
Conference_Titel :
Solid-State and Integrated Circuit Technology (ICSICT), 2010 10th IEEE International Conference on
Conference_Location :
Shanghai
Print_ISBN :
978-1-4244-5797-7
DOI :
10.1109/ICSICT.2010.5667827
