Audio AmplifierDesign MembersAbstractProblem StatementRedesign IssuesRedesign Issues Cont.Slide 7System OverviewDesign ConstraintsSlide 10Power SupplySlide 12Slide 13Operating FrequencySlide 15Signal-to-Noise Ratio ContinuedSlide 17Slide 18Slide 19Slide 20Slide 21Signal-to-Noise RatioSlide 23Slide 24Slide 25Efficiency (Transistors vs. Opamps)EfficiencySlide 28Slide 29Energy DisplaySunny Day/Rainy Day ScenarioCostSlide 33Final GoalsSummaryAcknowledgementsQuestions???Audio AmplifierSpring Midterm PresentationSpring Midterm PresentationDesign MembersJerome Buckingham – Team LeaderLaCurtis Banks – Member Terrance West – Member Lennon Brown III – Member Advisors:Dr. Roger KingDr. Raymond Winton Mr. Tim SchiltcherAbstractOur project will be to design and construct a power amplifier Our project will be to design and construct a power amplifier which accepts an incoming analog audio signal, amplifies it, and which accepts an incoming analog audio signal, amplifies it, and replays the new version of the signal in “real time” with a better replays the new version of the signal in “real time” with a better sound quality and added effects. sound quality and added effects. Objectives:Objectives:Design an audio amplifier that is ideal for customers looking for high Design an audio amplifier that is ideal for customers looking for high quality sound, but at a reasonable price. quality sound, but at a reasonable price. Add features such as: Add features such as: Energy Display Energy Display User level ControlUser level ControlProblem Statement These customers are searching for a good product which can produce a high quality of sound but at an inexpensive price. People are interested in increasing the sound quality of either their home entertainment system or car audio systems.Redesign IssuesPower TransistorPower TransistorDisadvantagesDisadvantagesSaturationSaturationI Bias (Problem)I Bias (Problem)Offset of OutputOffset of OutputNoise InterferenceNoise InterferenceRedesign Issues Cont.Power Operational AmplifiersPower Operational AmplifiersAdvantagesAdvantagesIntegrated Circuit Integrated Circuit PackagingPackagingShort-Circuit ProtectionShort-Circuit ProtectionThermal ProtectionThermal ProtectionProduce less distortion Produce less distortionRedesign Issues Cont.TMSVC33 DSP Starter KitTMSVC33 DSP Starter KitDisadvantagesDisadvantagesTime ConsiderationsTime ConsiderationsInsufficient Drivers for Display CapabilitiesInsufficient Drivers for Display Capabilities DSP5455 MicrocontrollerDSP5455 MicrocontrollerAdvantagesAdvantagesSmall, CompactSmall, CompactNecessary Drivers for Energy Display Necessary Drivers for Energy Display Process Signal With Real-Time Audio QualityProcess Signal With Real-Time Audio QualityCost EfficientCost EfficientSystem OverviewIncomingSignalPower SupplyDSP Microcontroller LCDAmplifierDesign ConstraintsOperating Frequency20Hz to 20kHzEfficiency 50% or greater efficiency maximum output power.Operating Temperature 45o C to 150oC, Marginal safety of 30oC.Distortion The amplifier will have a total harmonic distortion of 0.01%Size 5”x6”x9”Power Source+ 16 Volts DC. Thermal Protection Mode FeatureProtect components from overheating when improper loads are connected.Signal-to-Noise Ratio 80 dB or Better Cost$250WeightLess than 5 lbs.System OverviewIncoming SignalPower SupplyDSP Microcontroller LCDAmplifierPower SupplyPower Bridge NetworkEquationsVs (min) =.5*sqrt(2*PL*RL) = 15.5 V == 16V PL(max) = Vs * Is Therefore, Is = PL(max) / Vs = 60 W / 16V = 3.75 A == 4 ASystem OverviewIncoming SignalPower SupplyDSPMicrontroller LCDAmplifierDesign ConstraintsDesignConstraintTransistorsResultsOpampsResultsOperating Frequency20Hz to 20 kHz??? ???Operating FrequencyTransistor vs Op-AmpsTransistorTransistorOperational AmplifiersOperational Amplifiers20 – 20k20 – 20kamplified noise in signalamplified noise in signalDesign ConstraintsDesignConstraintTransistorResultsOpampsResultsOperating Frequency20Hz to 20 kHzSignal-to-Noise Ratio (SNR)80 dB or Better??? ???Pass PassSignal-to-Noise Ratio ContinuedTransistorsLow FrequenciesAmplified SignalInput SignalEquation:SNR (dB) = - 20 log (fsignal / fnoise)Signal-to-Noise Ratio ContinuedOpampsLow FrequenciesAmplified SignalInput SignalEquation:SNR (dB) = - 20 log (fsignal / fnoise)Signal-to-Noise Ratio ContinuedTransistorsMid FrequenciesAmplified SignalInput SignalEquation:SNR (dB) = - 20 log (fsignal / fnoise)Amplified SignalInput SignalSignal-to-Noise Ratio ContinuedOpampsMid FrequenciesAmplified SignalInput SignalEquation:SNR (dB) = - 20 log (fsignal / fnoise)Signal-to-Noise Ratio ContinuedTransistorsHigh FrequenciesAmplified SignalInput SignalAmplified SignalInput SignalEquation:SNR (dB) = - 20 log (fsignal / fnoise)Signal-to-Noise Ratio ContinuedOpampsHigh FrequenciesAmplified SignalInput SignalAmplified SignalInput SignalAmplified SignalInput SignalEquation:SNR (dB) = - 20 log (fsignal / fnoise)Signal-to-Noise RatioStereo OutputTransistor OutputOpamp OutputBest Case Best Case SNRSNR-79.19 dB -47.37 dB -55.73 55.73 dBdBWorse Worse Case SNRCase SNR-30.09 dB -7.88 dB -17.96 17.96 dBdBAvg. SNRAvg. SNR -54.64 dB -27.63 dB -36.85 36.85 dBdBTest Frequencies: 75Hz, 200Hz, 250Hz, 500Hz, 1kHz, 5.5kHz,10kHz, 17.5kHz, 20.1kHzDesign ConstraintsDesignConstraintTransistorsResultsOpampsResultsOperating Frequency20Hz to 20 kHzSignal-to-Noise Ratio (SNR)PassFailPassFailApprox =54.6 dB80 dB or BetterSystem OverviewIncoming SignalPower SupplyDSPMicrontroller LCDAmplifierDesign ConstraintsDesignConstraintTransistorsResultsOpampsResultsOperating Frequency20Hz to 20 kHzSignal-to-Noise Ratio (SNR)80 dB or BetterEfficiency 50% or better ??? ???PassFailPassFailEfficiency(Transistors vs. Opamps)Sample Calculations:Avg. Efficiency = (Pin / Pout) * 100%EfficiencyAvg. EfficiencyTransistorsEfficiency = 70.1%70.1%OpampsEfficiency = 73.7%73.7%Design ConstraintsDesignConstraintTransistor ResultsOpampResultsOperating Frequency20Hz to 20 kHzSignal-to-Noise Ratio (SNR)80 dB or BetterEfficiency 50% or betterSize 5”X6”X9” --- ---Cost ??? ???PassFailPassPassPassFail250.00System OverviewIncoming SignalPower SupplyDSPMicrocontroller
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