CS-EE 481 Spring 2007

March, 2007 Sublimity Audio 1

University of Portland School of Engineering

Project Sublimity AudioStereo Class-D Audio Amplifier

TeamJoe Baird

Luke Raynor

Aaron Taylor

AdvisorDr. Osterberg

Industry RepresentativeMike Desmith (Intel)

CS-EE 481 Spring 2007

March, 2007 Sublimity Audio 2

University of Portland School of Engineering

Overview

• Introduction

• Scorecard

• Additional Accomplishments

• Plans

• Issues/Concerns

• Conclusions

CS-EE 481 Spring 2007

March, 2007 Sublimity Audio 3

University of Portland School of Engineering

Introduction

• Stereo input, 2.1 Output

• Switching rather than linear

• Much more efficient than “conventional” class-AB amplifiers

CS-EE 481 Spring 2007

March, 2007 Sublimity Audio 4

University of Portland School of Engineering

Introduction

CS-EE 481 Spring 2007

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University of Portland School of Engineering

Classic Class AB Amp

CS-EE 481 Spring 2007

March, 2007 Sublimity Audio 6

University of Portland School of Engineering

Simple Class-D Amp

CS-EE 481 Spring 2007

March, 2007 Sublimity Audio 7

University of Portland School of Engineering

Commercial Class-D Amp Specifications VS Sublimity Audio Class-D Amp

Specification Alpine MRP-M450Value

Sublimity AudioValue

Power Requirements 14.4V DC (11V to 16V) + /- 12V DC for component power Variable power rails – Default to +/- 12V for left/right Ch, 24V for sub CH

Efficiency 80 % 80 %

Input Sensitivity (For Rated Power):

0.2V to 4.0V N/A

RMS Power (at 14.4V THD+N, 20Hz-20kHz)

Per channel into 4 ohms: 220W x 1 (1% THD) At 12V: 90W TotalPer Right/Left Channel into 4 ohms: 18WSubwoofer Channel into 4 ohms: 54W

Channels 1 Channel (Mono) Operation 2 Right/Left Channels1 Subwoofer Channel

Frequency Response 20Hz - 200Hz (+3/-3dB) Right/Left Channel: 125Hz – 20kHzSubwoofer Channel: 20Hz – 150Hz

Signal to Noise (S/N) 90dBA (Reference to Rated Power) N/A

Input Impedance 10k Ohm N/A

CS-EE 481 Spring 2007

March, 2007 Sublimity Audio 8

University of Portland School of Engineering

Scorecard

• Left/Right Ch Gate Driver/FETs Completed

• Left/Right Ch Output Filter Completed

• Left/Right Ch Preamp (95%) Completed

• Left/Right Ch PWM Generator Completed

• Class-AB Comparison Amplifier Completed

CS-EE 481 Spring 2007

March, 2007 Sublimity Audio 9

University of Portland School of Engineering

Full Class-D Schematic

CS-EE 481 Spring 2007

March, 2007 Sublimity Audio 10

University of Portland School of Engineering

Left/Right Channel Demowithout pre-filtering

CS-EE 481 Spring 2007

March, 2007 Sublimity Audio 11

University of Portland School of Engineering

Plans

• Construct full-bridge sub channel

• Solder a single half-bridge channel to demonstrate EMI effects

• Construct a speaker box

• Measure amplifier parameters

• Update TOPs document

CS-EE 481 Spring 2007

March, 2007 Sublimity Audio 12

University of Portland School of Engineering

Milestones

Number Description Original9/25/06

Previous11/30/06

Present1/30/06

1 Product Approval 10/22/06 10/22/06 10/22/06

2 Plan Approval 11/10/06 11/10/06 11/10/06

3 Circuit Diagram 12/1/06 12/1/06 12/1/06

4 Design Release 12/08/06 12/08/06 12/08/06

5 TOP’s Approval 02/23/07 02/23/07 02/23/07

6 Unit Testing Completed 3/23/07 3/23/07 04/10/07

7 Prototype Release 04/13/07 04/13/07 04/13/07

8 Founder’s Day 04/17/07 04/17/07 04/17/07

9 Final Report 04/27/07 04/27/07 04/27/07

10 Party with Stereo 4/27/07 4/27/07 4/27/07

CS-EE 481 Spring 2007

March, 2007 Sublimity Audio 13

University of Portland School of Engineering

Concerns/Issues

• Building a nice speaker box

• Minimizing EMI as much as possible

CS-EE 481 Spring 2007

March, 2007 Sublimity Audio 14

University of Portland School of Engineering

Conclusions

• Left/Right Ch Completed minus simple pre-filter• Class-AB Comparison Amp Completed• Solder a Separate Half-Bridge Channel• In Process of Updating TOPs• Biggest Enemy = EMI!!!

• Does anyone have a question?