Integrated stereo /spl Delta//spl Sigma/ class D amplifier

Gaalaas, Eric; Liu, B.Y.; Nishimura, Naoaki; Adams, Robert; Sweetland, Karl

doi:10.1109/jssc.2005.856266

Cited by 74 publications

(6 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Incorporating the LC into the feedback loop [7], [12], [24] is necessary for the proposed capacitive feedback scheme. 1 Since the output stage generates [6], [8], [9], [10], [11] high-frequency switching signals at V SW , taking feedback from these nodes would result in a residual error signal (V IN − V OUT /8) that would saturate A 1 , as shown in Fig. 3(a).…”

Section: A Overviewmentioning

confidence: 99%

“…In high-end applications, audio digital-to-analog converters (DACs) with a dynamic range (DR) of above 130 dB are commercially available [1], [2], [3], [4], matching that of the human ear. However, the DR of typical monolithic class-D audio amplifiers is much lower, only around 110 dB for analog-input designs [5], [6], [7], [8], [9], [10] and up to about 115 dB for digital-input designs [11], [12], [13], [14].…”

mentioning

confidence: 99%

See 1 more Smart Citation

A 121.4-dB DR Capacitively Coupled Chopper Class-D Audio Amplifier

Zhang

Berkhout²,

Makinwa

et al. 2022

IEEE J. Solid-State Circuits

View full text Add to dashboard Cite

This article presents a class-D amplifier (CDA) with high dynamic range (DR). To eliminate the typically dominant noise contribution of a resistive feedback network, the input and feedback signals are chopped and applied to a capacitive feedback network. However, this leads to high-voltage (HV) transients at the input of the loop filter, which, due to timing and impedance mismatch in the chopped feedback network, could degrade linearity and even overstress low-voltage (LV) core devices. Robust processing of the HV chopped feedback signal is guaranteed with chopper timing skew correction, chopper impedance matching, and deadbanding. The prototype, implemented in a 180-nm bipolar-CMOS-DMOS (BCD) process, achieves 121.4 dB of DR, 5.9 dB higher than state-of-the-art closed-loop CDAs, and 8-μV RMS output-referred noise (A-weighted). It also achieves a peak total harmonic distortion (THD) + N of −109.8 dB and a peak efficiency of 93%/88% while driving 15 W/26 W into an 8-/4-load.

show abstract

Section: A Overviewmentioning

confidence: 99%

mentioning

confidence: 99%

A 121.4-dB DR Capacitively Coupled Chopper Class-D Audio Amplifier

Zhang

Berkhout²,

Makinwa

et al. 2022

IEEE J. Solid-State Circuits

View full text Add to dashboard Cite

show abstract

“…Among these building blocks, the audio amplifier has to drive a resistive output load with very good linearity and therefore tends to consume large power. To perform the audio signal amplification with minimum power consumption, a class-D amplifier has been widely adopted [4,5,6,7,8,9,10,11,12,13,14].…”

Section: Introductionmentioning

confidence: 99%

An analog sigma-delta modulator with shared operational amplifier for low-power class-D audio amplifier

Noh

Lee

Yoo

2015

IEICE Electron. Express

View full text Add to dashboard Cite

To minimize the power consumption of an analog sigma-delta modulator (SDM), a fifth-order loop filter of the SDM has been realized with only three operational amplifiers (op-amp). The analog SDM with shared opamp is applied to a class-D amplifier for a digital hearing aid. The class-D amplifier with the analog SDM has been realized in a standard 0.13-µm CMOS process. The maximum output power level of the class-D amplifier is 1.13-mW for a load with 46.5-Ω DC resistance. The total harmonic distortion+noise (THD+N) and the dynamic range (DR) of the class-D amplifier are 0.0038-% and 96-dB, respectively. The fifth-order analog SDM with shared op-amp consumes only 0.2-mW from a 1.2-V power supply.

show abstract

“…Then, the integrator output is fed to a comparator with a hysteresis window. This approach gives a second order loop transfer in the audio band using a single integrator [8]. A hysteretic feedback loop is shown in Fig.…”

Section: Hystereticmentioning

confidence: 99%

Active PWM ripple reduction in class-d amplifiers using digital loop filters

Lokin¹

View full text Add to dashboard Cite

The research field around sound reproduction is driven by a desire to continuously pack more powerful amplifiers in a small fan-less enclosure while providing state-of-the-art noise and distortion performance. Class-D amplifiers are a perfect candidate for these requirements, specifically because of the inherently low dissipation in their switching power stage with respect to more conventional linear amplifiers. There is, however, always a caveat: switching high currents at high frequencies causes electromagnetic emissions that could interfere with the correct operation of other electronic devices. Regulations limit the amount of electromagnetic interference (EMI) that devices are allowed to emit to maintain interoperability between the many electronic devices in the Internet of things (IoT) era.Speakers are commonly connected to an amplifier using leads of several meters. These leads double as an antenna for high frequency signals above the audio band, such as the switching frequency and its harmonics or parasitic ringing in the output stage, thereby causing unwanted radiated emissions. This thesis is focused on reducing the EMI due to the residual power after the output filter at the pulse-width modulation (PWM) frequency, the so called ripple. Examples in literature reduce the power at the PWM frequency and its harmonics by applying spread spectrum modulation to smear power out over a larger bandwidth. However, in this way they still radiate the same amount of power, just not concentrated at distinct frequencies. To reduce the ripple current through the speaker leads, it is possible to use a higher order filter, use a multi-phase or multi-level output stage or to inject a cancellation signal after the output filter. In the research field of power electronics, cancellation schemes have been presented. First the disturbance is sensed and processed and afterwards a cancellation signal is synthesized and injected into the circuit. The processing can be done using a feedback or feed-forward topology, each having its advantages and disadvantages.An extensive case study on multi-phase systems is done to evaluate their merits in reducing the ripple current after the output filter. In a multiphase system, multiple half-bridges are combined in a parallel fashion to drive one or both sides of the load. Interleaving of the PWM carriers in the modulator corresponding to each half-bridge provides a reduction in the observed ripple current after combining the half bridge outputs in the output filter. The effect of adding more phases on the amount of ripple is vii ix ABSTRACT high-frequency poles.In summary, this thesis has shown a technique to reduce the ripple current after the output filter. Thereby the amount of EMI that can be radiated off the speaker leads decreases. The effect of unit delays in the loop has been mitigated by applying a special filter design method to obtain a more stable system. A prototype has been made around an existing amplifier to show the effectiveness of the proposed feedback ripple reduction so...

show abstract

Integrated stereo /spl Delta//spl Sigma/ class D amplifier

Cited by 74 publications

References 3 publications

A 121.4-dB DR Capacitively Coupled Chopper Class-D Audio Amplifier

A 121.4-dB DR Capacitively Coupled Chopper Class-D Audio Amplifier

An analog sigma-delta modulator with shared operational amplifier for low-power class-D audio amplifier

Active PWM ripple reduction in class-d amplifiers using digital loop filters

Contact Info

Product

Resources

About