D Amplifier Solutions & Practical Considerations
OBJECTIVE: To research common switching (class D) amplifier design techniques and their implementation in various consumer applications.
RESEARCH SUMMARY: Class-D_amp_research.pdf (21 pages)
NOTE: The above document is only a rough outline summarizing key information from my research. I had hoped to produce a well-written report; however, the breadth of my research would’ve required a 50+ page paper which I regretfully did not have time to write. Nonetheless, this outline provides a useful summary of my research on Class D amplifier design and implementation.
- Class D amplifier topologies
- Common applications
- Tradeoffs between switching amps & linear amps
- Practical considerations when designing & implementing switching amplifier solutions
- Emerging device technologies
· Class D history
· Class D topologies & modulation techniques
· Output filter vs. filterless topologies
· Output switching circuits (half-bridge vs. H-bridge)
· Sources of distortion in class D amps
· EMI & noise considerations
· Thermal considerations
· PCB layout considerations
· Power supply requirements & considerations
· Typical class D solutions for:
o Low power mobile applications
o High power applications
o High fidelity applications
REFERENCES: Interested readers are encouraged to review the extensive list of online references (below) gathered during my research.
Click HERE for the printable list.
Class D Amplifiers Empower Mobile Multimedia
Designing With Class D Amplifier ICs
Class D Audio Amplifier Basics
A Class D audio amplifier is basically a switching amplifier or PWM amplifier. There are a number of different classes of amplifiers. This application note takes a look at the definitions for the main classifications.
Class D Audio Amplifier Performance Relationship to MOSFET Parameters
This application note discusses key parameters to be considered in the selection of MOSFETs for class D audio amplifier and their relationship with amplifier’s performance such as efficiency, EMI, and THD. In addition, benefits and advantages of IR Digital Audio MOSFETs in class D audio amplifier are presented.
PCB Layout with IR Class D Audio Gate Drivers
…The layout of a class D amplifier remains the most obscure part of the design process. The purpose of this application note is to highlight aspects of the PCB layout which require a designer’s careful attention.
IRS2092(S) Functional Description
The IRS2092(S) is a Class D audio amplifier driver with integrated PWM modulator and over current protection. Combined with two external MOSFETs and a few external components, the IRS2092(S) forms a complete Class D amplifier with dual over current, and shoot-through protection, as well as UVLO protection for the three bias supplies.
IRS2093M Functional Description
The IRS2093M is a four channel Class D audio amplifier driver with integrated PWM modulators and over current protection. Combined with eight external MOSFETs and external passive components, the IRS2093M forms four complete Class D amplifiers.
Class D Amplifier FAQ
This FAQ is intended to capture a variety of knowledge about the selection, application, and measurement of Class D amplifiers. The emphasis of this FAQ is towards Class D amplifiers in the 0.5W to 2W range intended for portable media devices such as mobile phones, portable DVD players, and portable navigation systems. However, the vast majority of this information can be applied to Class D amplifiers from milliwatts to kilowatts of output power.
Commercializing Class D Amplifier Technologies
The popularity of commercial audio systems having large numbers of channels has resulted in a growing demand for smaller, lighter, and less expensive multichannel power amplifier products. This paper describes how careful integration of power factor corrected switchmode power supplies, class D power amplifiers, and digital signal processors yields high power density and especially reliable and electromagnetically quiet products at a reasonable cost.
Class D Audio Amplifiers - Theory and Design
Minimize Noise in Audio Channels with Smart PCB Layout
Class D Amplifiers:
Fundamentals of Operation and Recent Developments
Considerations for a Class D Amplifier
Reference Design for
a Class-D, 2.1 Channel, Audio Amplifier for an MP3
Player Docking Station
Overview of 2.1
(Satellite/Subwoofer) Speaker Systems
- for 2.1 stereo PC speakers
Mode Minimizes Electromagnetic Interference in Class D Amplifiers
- no output filter needed in class D!
Reduce EMI from Class
D Amplifiers Using New Modulation Techniques and Filter Architectures
Complete Audio Record/Playback for GSM/GPRS Cell Phones
Class D Audio
Amplifiers Save Battery Life – 2002
Class D Audio
Amplifier Output Filter Optimization – 2002
Considerations in Ceramic Speaker Applications - (pg 3-6)
Class G and
Charge-Pump Technologies Maximize Efficiency in Boosted Amplifiers with Minimal
- class D cannot drive ceramic (piezoelectric) speakers
Ensure Quality Audio in Portable Devices
Personal Mobile Devices – Selection Guide
Analog Product Guide 2009 Vol
Filterless Class D Amplifiers
Managing EMI in Class D Audio Applications
Noise, TDMA Noise, and Suppression Techniques
LM49352 - Mono Class D Audio Codec Subsytem with
Ground Referenced Headphone Amplifiers, Earpiece Driver, and Audio DSP from the
Semiconductor Extends Family of Low-Power, Premium Quality Audio Subsystems for
LM48511 - 3W, Ultra-Low EMI, Filterless, Mono, Class D
Audio Power Amplifier with Spread Spectrum
Semiconductor’s New Audio Amplifier with Spread Spectrum and Integrated Boost
Architecture Reduces EMI Sensitivity in Portable Applications
Reference Design 167 - High Efficiency Portable Media
Player (PMP) Docking Station
LM4962 Stereo Ceramic Speaker Driver Application Note
- not class D
Class D Audio Amplifiers: What, Why, and How
Stereo Audio Codecs Deliver
Best Audio Experience with Lowest Power Dissipation
FIRST PULSE DENSITY
MODULATION (PDM) DIGITAL-INPUT CLASS D AUDIO AMPLIFIER
D2-814xx PWM Controllers – The World’s First Intelligent Digital Amplifier Solution
D2AUDIO® TXF15-2 – Advanced Audio Processing Solution for Stereo, 2.1 and Bi-Amp TV’s
Call for comment on
reaffirmation of AES17-1998