A Class-D Amplifier with Digital PWM and Digital Loop-Filter using a Mixed-Signal Feedback Loop

Mario Auer, Timucin David Karaca

Research output: Chapter in Book/Report/Conference proceedingConference paperpeer-review


A digital class-D audio amplifier is presented that is based on digital pulse-width modulation (PWM) and a com- bination of digital and analog feedback. Unlike other recent im- plementations for low-power applications this amplifier directly accepts digital input as the digital-to-analog conversion is an inherent feature of the presented topology.
The feedback topology uses a hybrid scheme with digital feedback to improve the performance of the PWM and analog- feedback to mitigate analog imperfections and to improve power supply rejection. Because of the proposed feedback scheme, the requirements on the analog-to-digital converter (ADC) in the feedback loop are greatly relaxed allowing the use of a continuous-time ∆Σ-modulator.
The class-D amplifier was realized in a standard 180nm CMOS technologies and drives 1.2W into an 8Ω load and achieves a total harmonic distortion plus noise (THD+N) of −96dB, a signal-to-noise ration (SNR) of 99.9dB having an efficiency of 91%.
Original languageEnglish
Title of host publicationESSCIRC 2019 - IEEE 45th European Solid State Circuits Conference (ESSCIRC)
PublisherInstitute of Electrical and Electronics Engineers
Number of pages4
ISBN (Electronic)978-1-7281-1550-4
Publication statusPublished - Nov 2019
Event49th European Solid-State Circuits Conference: ESSCIRC 2019 -
Duration: 23 Sept 201926 Sept 2019


Conference49th European Solid-State Circuits Conference
Abbreviated titleESSCIRC
Internet address

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