A 3.4W digital-in class-D audio amplifier

Berkhout, Marco; Dooper, L.

doi:10.1109/esscirc.2011.6044921

Cited by 3 publications

(3 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The third term comprises the components related to the carrier, which are the carrier, its harmonics, and the intermodulation components between the input signal and the carrier. Although (10) is based on the 1FB-CDA, we will later show in Section III-C that the derived Fourier series expression can be easily extended to other closed-loop topologies, e.g., the 2FB-CDA.…”

Section: ) Fourier Series Expression For Noise-free Supply and Infinmentioning

confidence: 99%

“…Step 2-Derivation of the Output PWM Signal : The general Fourier series expression of rectangular pulses is given by (9) Substituting (8) into (9), the PWM signal expression is (10) where Equation (10) is interpreted as follows. The first two terms are, as in (4) for the open-loop CDA, the inconsequential constant dc offset and the amplified replica of the input signal, respectively.…”

Section: ) Fourier Series Expression For Noise-free Supply and Infinmentioning

confidence: 99%

“…This drawback arises primarily because of the architecture of the switching-mode output stage. For example, the fundamental PSRR of an open-loop CDA is merely 6 dB [10], [11]; in this paper, the fundamental PSRR refers to the PSRR due to the nonlinear component whose frequency is the same frequency as the frequency of supply noise, typically 100 Hz or 120 Hz.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Power Supply Noise in Analog Audio Class D Amplifiers

Shu

Chang

2009

IEEE Trans. Circuits Syst. I

View full text Add to dashboard Cite

A potential drawback of class D amplifiers (CDAs) is their relatively poor tolerance to power supply noise. It has been recently established by means of a linear model that the manifested nonlinearities due to the supply noise are the fundamental noise frequency component and second-order intermodulation components, qualified by the power supply rejection ratio (PSRR) and intermodulation distortion (IMD), respectively. In this paper, multidimensional Fourier series analysis is applied to open-loop, single-, and double-feedback pulsewidth modulation CDAs, and expressions for PSRR, IMD, and fold-back distortion (FBD) are derived. This analysis takes into account the nonlinear pulse modulation process (unaccounted for in the linear model), and all components of PSRR and IMD nonlinearities are hence modeled. It is shown that the first-harmonic PSRR and third-order IMD components, which are usually ignored in CDAs and linear amplifiers, are significant and that, under certain conditions, the third-order IMD components can be higher than the second-order IMD components. It is also shown that the loop gain should be high for high PSRR and low IMD. Furthermore, significant FBD can arise due to the intermodulation between the supply noise, the input signal, and the carrier, and interestingly, the FBD in closed-loop CDAs is more serious than that in open-loop CDAs. The analyses herein are verified by computer simulations and on the basis of measurements on a prototype CDA IC and on other hardware realizations.

show abstract

Section: ) Fourier Series Expression For Noise-free Supply and Infinmentioning

confidence: 99%

Section: ) Fourier Series Expression For Noise-free Supply and Infinmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation