Electromagnetic evaluation of Class-D switching schemes

Karaca, Timucin; Deutschmann, Bernd

doi:10.1109/prime.2015.7251347

Cited by 9 publications

(10 citation statements)

References 2 publications

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“…4 has to be reduced. By going to a BTL topology, a ternary modulation scheme [2] can be used that adds a degree of freedom to choose the CM level. Dissipation can be reduced by reducing the idle output CM voltage and thereby setting V DS over the MOS transistors closer to ground.…”

Section: B Low Common-mode Signalingmentioning

confidence: 99%

“…7 shows the total dissipation as function of the instantaneous output voltage. The dissipation curve for active ripple reduction with conventional AD or BD modulation [2] is drawn to show the advantage in power dissipation of the low CM switching over normal AD or BD modulation. As audio has a high peak to average power ratio [15], most of the signal content resides in the valley of the…”

Section: B Low Common-mode Signalingmentioning

confidence: 99%

“…5, (2) is applied. The resulting loop filter has a resonator at f pwm = 768 kHz, because of the 1/NTF operation in (2). The loop filter transfer function is shown in Fig.…”

Section: Filter Synthesismentioning

confidence: 99%

“…As settop box or car audio amplifier systems connect the speakers via long leads, these leads will function as an antenna for the common-mode (CM) switching residue. Class-D amplifiers can utilize different modulation schemes when their output stage is in a bridge-tied-load (BTL) configuration [2]. The EMI reduction techniques that are explained later depend on the modulation scheme that is used, hence we will now first discuss these modulation schemes.…”

Section: Introductionmentioning

confidence: 99%

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EMI Reduction in Class-D Amplifiers by Actively Reducing PWM Ripple

Lokin

Zee

Schinkel³

et al. 2020

IEEE Trans. Circuits Syst. I

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Class-D amplifiers switch high voltages and currents at high frequencies and hence produce electromagnetic interference (EMI). This work presents a technique to reduce the high frequency ripple, which is still present after the output filter. A Class-A ripple reduction amplifier is put in parallel to the output of the Class-D amplifier, each having their own feedback loop with digital filters. High ripple reduction loop gain is achieved at the PWM frequency by using a resonator as digital loop filter. Dissipation in the Class-A amplifier is reduced by using a low common-mode signaling technique. Commonmode and differential-mode switching components at the PWM frequency are reduced by 27 dB and 18 dB respectively. Total system efficiency is 79% at 40 W output power.

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Section: B Low Common-mode Signalingmentioning

confidence: 99%

Section: B Low Common-mode Signalingmentioning

confidence: 99%

“…5, (2) is applied. The resulting loop filter has a resonator at f pwm = 768 kHz, because of the 1/NTF operation in (2). The loop filter transfer function is shown in Fig.…”

Section: Filter Synthesismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

EMI Reduction in Class-D Amplifiers by Actively Reducing PWM Ripple

Lokin

Zee

Schinkel³

et al. 2020

IEEE Trans. Circuits Syst. I

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show abstract

“…In recent architectures of Class D audio amplifier topologies, the inductance of the speaker itself is incorporated as part of a filter to extract the audio component from the pulse width modulation (PWM) square wave output [5], [6]. This socalled "filterless" topology eliminates the output filter, but might increase the EMI emitted by the speaker cables [7].…”

Section: Introductionmentioning

confidence: 99%

Emission reduction in Class D audio amplifiers by optimizing spread spectrum modulation

Deutschmann

Winkler

Karaca

2015

2015 10th International Workshop on the Electromagnetic Compatibility of Integrated Circuits (EMC Compo)

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Due to their high efficiency compared to conventional Class AB amplifiers, Class D audio amplifiers have increasingly become the amplifier of choice especially for low power applications such as portable electronics. However, Class D amplifiers are still a major source of electromagnetic emission of the electronic applications in which they are used. In this paper the benefits of using spread spectrum techniques in order to reduce the emission of Class D audio amplifiers is highlighted. Based on IC-level measurement results of a 10W Mono Class D speaker amplifier, that allows to be synchronized to an external clock, it is shown how spread spectrum parameters like deviation, modulation frequency and modulation signal can be optimized in order to maximize the reduction of the emission.

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Motivation and Fundamentals

Funk¹,

Wicht²

2020

Integrated Wide-Bandwidth Current Sensing

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Electromagnetic evaluation of Class-D switching schemes

Cited by 9 publications

References 2 publications

EMI Reduction in Class-D Amplifiers by Actively Reducing PWM Ripple

EMI Reduction in Class-D Amplifiers by Actively Reducing PWM Ripple

Emission reduction in Class D audio amplifiers by optimizing spread spectrum modulation

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