On designing sigma-delta converter systems for class-D power amplifiers

Kok, Robert; Weber, David M.

doi:10.1109/afrcon.1999.821854

Cited by 3 publications

(1 citation statement)

References 2 publications

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“…A limited number of publications demonstrate, mainly from an experimental point of view, the advantages of SDM over regular PWM to solve EMI, power factor and acoustic tones [1], [3], [24]. However, 0885-8993/$25.00 © 2007 IEEE a comparison between SDM and any kind of RPWM is still lacking and would be of great interest.…”

Section: Introductionmentioning

confidence: 96%

Randomized Carrier PWM With Exponential Frequency Mapping

Carlosena

Chu

Bakkaloglu

et al. 2007

IEEE Trans. Power Electron.

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Pulsewidth modulation (PWM) and sigma-delta modulation (SDM) have been used in several high linearity, high accuracy power delivery applications such as dc-dc power converters, audio, and radio frequency power amplifiers and data converters. While PWM can generate high linearity signals with high efficiency, it suffers from discrete tonal output spectrums. SDM, on the other hand, can generate high linearity output spectrums with shaped quantization noise spectrums and lower efficiencies due to oversampling requirements. In this paper we present a particular class of carrier frequency modulated PWM (CFMPWM), which spreads the tonal content of regular PWM uniformly in frequency and reduces the baseband noise with respect to SDM by up to 15 dB. The new modulation scheme preserves the high efficiency properties of PWM. An approximate method to estimate the spectrum of CFMPWM signals with both deterministic and random modulation is also presented. Simulation results and experimental data are reported to analyze the spectral spreading properties of the proposed CFMPWM scheme. Index Terms-Carrier frequency modulated pulsewidth modulation (CFMPWM), electromagnetic interference (EMI), pulse density modulation (PDM), sigma-delta modulation (SDM).

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Section: Introductionmentioning

confidence: 96%

Randomized Carrier PWM With Exponential Frequency Mapping

Carlosena

Chu

Bakkaloglu

et al. 2007

IEEE Trans. Power Electron.

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Randomized carrier PWM with exponential frequency mapping

Carlosena

Chu

Bakkaloglu

et al.

2006 IEEE International Symposium on Circuits and Systems

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Pulse Width Modulation (PWM) and Sigma Delta attainable with respect to regular PWM. A limited number of Modulation (SDM) have been used in several high linearity, publications show, mainly from an experimental point of high accuracy power delivery applications such as DC-DC view, the advantages of SDM over plain PWM to solve EMI, power converters, audio and RF power amplifiers as well as in power factor and acoustic tones [1,3,9]. data converters. In this paper we present a particular class of Carrier Frequency Modulated PWM (CFMPWM), which Since RPWM methods have been mainly developed for spreads the tonal content of regular PWM uniformly in Power Electronics applications, theoretical procedures to frequency and reduces the baseband noise with respect to SDM estimate the spectral properties of a given scheme are mostly by up to 15 dB. The new modulation scheme preserves at the based on the time Probability Density Function (PDF) of the same time the high efficiency properties of PWM. An parameter to be randomized (namely, period, width, duty approximate method to estimate the spectrum of CFMPWM cycle). This analysis is more straightforward for digital signals with both deterministic and random modulation is also microcontroller based implementations, where PWM signal presented. Simulation results and experimental data are icrated based However,atim e P WM s ignal reported to analyze the spectral spreading properties of the is generated digitally. However, time PDF based analysis proposed CFMPWM scheme. poses serious limitations for continuous-time highfrequency, fully integrated implementations where the I. INTRODUCTION randomization possibilities are less flexible. Although SDM Pulse Width Modulation (PWM) and Pulse Density and RPWM have been compared against plain PWM, Modulation (PDM) -in particular Sigma Delta Modulation spectral content of SDM with respect to RPWM have not(SDM)-have been used in several high linearity and high been analyzed. Also, the selection of a randomization accuracy switched-mode power delivery applications such as technique and its associated PDF to obtain a prescribed DC-DC power converters, audio and RF power amplifiers[1-spectral profile has not been addressed before. Although the 4]. In several applications where conducted and radiated problem is not solvable for a general PDF, a statistical electromagnetic interference (EMI) is a concern, wide-band approximation is critical for noise shaping applications. shaped noise content of SDM is preferred to inherently tonal This aper is organized as follows: in section II an content of PWM. SDM is also preferred in low frequency

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Realization Study of Class D Power Amplifier by Sigma-Delta Modulation

Hsieh

Chen²,

Liu³

2005 International Conference on Power Electronics and Drives Systems

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On designing sigma-delta converter systems for class-D power amplifiers

Cited by 3 publications

References 2 publications

Randomized Carrier PWM With Exponential Frequency Mapping

Randomized Carrier PWM With Exponential Frequency Mapping

Randomized carrier PWM with exponential frequency mapping

Realization Study of Class D Power Amplifier by Sigma-Delta Modulation

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