A Low Quiescent Current, Low THD+N Class-D Audio Amplifier With Area-Efficient PWM-Residual-Aliasing Reduction

Chien, Shih-Hsiung; Chen, Yiwen; Kuo, Tai‐Haur

doi:10.1109/jssc.2018.2873613

Cited by 13 publications

(13 citation statements)

References 14 publications

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“…Moreover, since the IR drop induced by the PWM components is attributed to the ripple current, the relatively large inductance exhibited in a loudspeaker helps keep this distortion below −100 dB. The constant HD3, on the other hand, is attributed to the inherent PWM residual aliasing distortion and therefore is independent of Δ𝑡𝑡 [20].…”

Section: B Impact Of Im On Linearitymentioning

confidence: 99%

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A Chopper Class-D Amplifier for PSRR Improvement Over the Entire Audio Band

Zhang

Rozsa

Berkhout³

et al. 2022

IEEE J. Solid-State Circuits

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The power supply rejection ratio (PSRR) of conventional differential closed-loop Class-D amplifiers is limited by the feedback and input resistor mismatch and finite CMRR of the OTA in the 1 st integrator. This paper presents a 14.4 V Class-D amplifier employing chopping to tackle the mismatch, thereby improving the PSRR. However, chopping-induced intermodulation within a PWM-based class-D amplifier can severely degrade PSRR and linearity. Techniques to mitigate such intermodulation are proposed and analyzed. To chop the 14.4V PWM output signal, a high-voltage (HV) chopper employing DMOS transistors is developed. Its timing is carefully aligned with that of the low-voltage (LV) choppers to avoid further linearity degradation. The prototype, fabricated in a 180 nm BCD process, achieves a PSRR of >110 dB at low frequencies, which remains above 79 dB up to 20 kHz. It achieves a THD of −109.1 dB and can deliver a maximum of 14 W into an 8-Ω load with 93% efficiency while occupying a silicon area of 5 mm 2 . Index Terms-Audio power amplifier, class-D amplifier, intermodulation, power supply rejection ratio (PSRR), total harmonic distortion (THD).C Fig. 1. Conventional closed-loop Class-D amplifier in a BTL configuration and sources of limited PSRR: feedback resistor mismatch, input resistor mismatch, and finite CMRR of the OTA in the 1 st integrator.

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Section: B Impact Of Im On Linearitymentioning

confidence: 99%

“…This is because in a closed-loop Class-D amplifier, the output of the loop filter 𝑉𝑉 𝐿𝐿𝐿𝐿 (Fig. 2) contains residual PWM ripple, which skews the center of the PWM pulses away from the triangle wave peaks [20], as shown in Fig. 7.…”

Section: B Impact Of Im On Linearitymentioning

confidence: 99%

A Chopper Class-D Amplifier for PSRR Improvement Over the Entire Audio Band

Zhang

Rozsa

Berkhout³

et al. 2022

IEEE J. Solid-State Circuits

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“…Its theoretical efficiency of 100% is often transformed into practical efficiencies of 95% and above in applications. Many controllers have been designed and developed for Class-D amplifiers to enhance intrinsic low THD and noise at output levels [31,32].…”

Section: Introductionmentioning

confidence: 99%

A Novel Fundamental Frequency Switching Operation for Conventional VSI to Enable Single-Stage High-Gain Boost Inversion with ANN Tuned QWS Controller

et al. 2021

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Single-stage high-gain inverters have recently gained much research focus as interfaces for inherent low voltage DC sources such as fuel cells, storage batteries, and solar panels. Many impedance-assisted inverters with different input stage configurations have been presented. To decrease passive component sizes, these inverters operate at high-frequency switching. The high-frequency switching optimizes the passive component sizes but introduces many challenges in the form of high-frequency inductor design, control complexity, high-frequency gate driver requirements, high semiconductor losses, and electromagnetic interferences. This article proposes a novel fundamental frequency switching operation for the conventional voltage source inverters (VSI) to operate as a single-stage high-gain inverter. As the novel operational strategy changes the behavior of conventional VSI from buck inverter to a boost inverter, it is hereafter termed as a novel inverter. By virtue of the operation strategy, switches withstand peak inverse voltage (PIV) equal to DC link voltage, unlike other impedance assisted boost inverters where PIV across switches is the amplified DC voltage. The proposed inverter can invert low-level DC voltage to high voltage AC with low total harmonic distortion (THD) in a single stage without the help of any external filter. A novel quarter-wave symmetric phase-shift controller is proposed for variable voltage and frequency control of proposed inverters tuned by a back-propagation thin-plate-spline neural network (BPTPSNN). Mathematical analysis with experimental validation is presented. Experimentation is carried out on a prototype of 2 kW for single-phase resistive load, induction motor, and non-linear loads.

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“…Improving these performances is especially important in battery powered portable devices. However, the full implementation of Class-D technology in portable devices required solving many problems in order to improve electroacoustic, energy, and electromagnetic compatibility (EMI) performance and filter the output signal [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Filterless, Digital Class-BD Audio Amplifiers with Constant Common Mode Output Voltage

et al. 2021

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This paper presents new and original architectures and implementations of two filterless, open-loop digital Class-BD audio amplifiers with constant common mode (CM) output voltage. The first, low-power amplifier consists of four ultrahigh-current EL7158 pin drivers, the OUT pins of which form the H bridge. The drivers are controlled from the extended LBDD PWM modulator and have appropriately set voltage levels on the VL and VH pins. The second proposed amplifier consists of two cooperating H-bridge power stages (HBS) implemented on complementary MOSFET pairs and powered by two different voltages. Both HBSs are driven by four EL7158 pin drivers having appropriately adjusted voltage levels on the VL and VH pins and controlled by an extended LBDD PWM modulator. The hybrid 9 bit DPWM modulator uses a linearized Class-BD double-sided modulation scheme with pre-compensation, enabling the most faithful emulation of natural NBDD PWM and, thus, providing attractive spectral characteristics at the DM output. Basic SPICE simulations and experimental results of the proposed digital Class-BD amplifiers were compared with the conventional digital Class-BD amplifiers. The elimination of CM signals significantly contributes to the reduction in electromagnetic interference (EMI), particularly those produced on the cables connecting the loudspeaker to the HBS terminal. Proposed Class-BD amplifiers with original and new topologies, due to their simple design and easy control (no galvanic isolation of control signals and no floating bias power supplies), which generate no CM voltage and feature excellent DM performance, similar to conventional Class-BD amplifiers, are very attractive solutions for filterless Class-BD amplifiers.

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A Low Quiescent Current, Low THD+N Class-D Audio Amplifier With Area-Efficient PWM-Residual-Aliasing Reduction

Cited by 13 publications

References 14 publications

A Chopper Class-D Amplifier for PSRR Improvement Over the Entire Audio Band

A Chopper Class-D Amplifier for PSRR Improvement Over the Entire Audio Band

A Novel Fundamental Frequency Switching Operation for Conventional VSI to Enable Single-Stage High-Gain Boost Inversion with ANN Tuned QWS Controller

Filterless, Digital Class-BD Audio Amplifiers with Constant Common Mode Output Voltage

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