WEEK 14

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

The final week. In this week 14, the Engineers day was successful done on 24 Apr, 2012 from 2pm to 5pm. Students have setup their project earlier, from 12noon - 2pm.

Engineer's Day is the day for FYP students to display their Final Year projects. It is a semesterly event that potrays the ingenuity, innovativeness, creativity and quality of our students and also staff. Therefore, it is an important event for it reflects who we are and what we are capable of.

For S112, Engineer's Day will coincide with UniKL-BMI Open Day, which promises more crowd than ever. The day also mark the first time ever Inter-Section Robotic Challenge and Inter-Section Innovation Challenge projects to be displayed. Beside adding new prizes to those two Inter-Section challenges, new prize category also be introduced for Top Blog, the best project reporting by students through the use of blog.

The assessor have evaluate my project on Engineers day:

1. Madam Mazhaniza Binti Mazumil
2. Tuan Haji Zainudin Bin Kornain

Other than that, even if the circuit for Class D does not work but I have made the best explanation about my project to the assessors and demo the circuit to both of them. This week, I'm also began to write the  FYP reports and technical paper for submit to my supervisor before 18 May, 2012.

WEEK 13

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

In week 13, I doing some discussion with my supervisor that the things I'm need to do for the Engineers day in next weeks. I'm have to prepare the poster and slide that will be used when the assessor to evaluate my project on Engineers day. For S112, the assessment (Demo Day) will start on 24 Apr, 2012 from 2pm to 5pm.

Picture below show  the example of my poster:

Picture 1: My poster for Engineers day

I'm continues doing the troubleshoot on circuit Class D audio amplifier to make it's become fully function. The picture below show the circuit For Class D audio amplifier:

Figure 22: The circuit for Class D audio amplifier

I'm also doing the research between topology comparison (linear vs. Class D). The primary and main difference between linear and Class D amplifiers the efficiency. This is the whole reason for the invention of Class D amplifiers. The linear amplifiers is also very inefficient at about 50% typically for a Class AB amplifier, whereas a Class D amplifier is more efficient, with values in the order of 90% in practical designs.

WEEK 12

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

For this week, I design the casing to cover the circuit for make it's more smart and easy to carry. For each casing, I have to drill the hole for the input (power supply), audio input and output (speaker). After placing each circuit in the casing, I must check all the circuit if it's function or not because some mistake such as broken connecting wire or other than that.

Pictures below show the casing that I have used for the each circuit:

Figure 19: The complete circuit of Class B in the casing

Figure 20: The complete circuit of Class AB using TDA 2030 in the casing

Figure 21: The complete circuit of Class AB using TDA 2003 in the casing

For the Class D audio amplifier, I have some doing troubleshoot to know what the problem and it still does not work. A class D amplifier is basically a switching amplier or PMW amplifier. Efficiency of 90-95% are possible.

WEEK 11

Audio Amplifier Performances

In this week, I design, test and construct the circuit of Class AB audio amplifier using TDA 2003 after buying all the component. The TDA 2003 provides a high output current capability, very low harmonic and cross over distortion.

TDA 2003 characteristics:

1. Operating power supply (Min 8, Max 18V)
2. Power dissipation at Tcase = 20W
3. Storage and junction temperature = -40 to 150 C
4. Frequency response = 40 - 15000 Hz

The pictures below is the circuit of Class AB audio amplifier  using TDA 2003 that I'm successful design and construct:

Figure 16: The complete circuit of Class AB using TDA 2003

Figure 17: Testing circuit with Function generator and Oscilloscope

Figure 18: The result displays at Oscilloscope

WEEK 10

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

For this week, I'm doing some discussion with my supervisor to design and construct the another circuit of Class AB audio amplifier using TDA 2003. Objective doing the another circuit is want to make comparison between using TDA 2003 and TDA 2030. 

Other that, I'm doing some research about this TDA 2003 and go buying all the components. Picture below is the circuit diagram that I'm being used:

Figure 14:Circuit diagram TDA 2003

Figure 15: Connection diagram 

Component:

1. IC = TDA 2003
2. Resistor = 15K, 3.3R, 220R and 1R
3. Capacitor = 10uF, 100uF, 100uF, 1000uF, 0.1 and 0.1
4. Speaker = 8 ohm
5. Heat sink
6. Variable resistance

WEEK 9

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

For week 9, I doing discussion with my supervisor for design n construct the circuit of Class AB Audio amplifier using TDA 2030. After successful design and construct this circuit, I'm test the circuit in lab to getting the result displays at Oscilloscope.

The pictures below is the circuit of Class AB Audio amplifier  using TDA 2030 that I'm successful design and construct:

Figure 13: The complete circuit of Class AB using TDA 2030

Figure 14: Testing circuit with Function generator and Oscilloscope

Figure 15: The result displays at Oscilloscope

For this circuit, the noise very high and so that we cannot hear the audio properly. 

WEEK 8

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

In this week, continue construct the circuit of Class B audio amplifier and test the circuit in lab. After finish and testing, I'm doing some troubleshoot for this circuit because I'm getting the low sound at the output (speaker).

After troubleshoot, the sound become clear And very good. The pictures below is the circuit of Class B audio amplifier that I'm have successful design and construct.

Figure 10: The complete circuit of Class B

Figure 11: Testing circuit with Function generator and Oscilloscope

Figure 12: The result display at Oscilloscope

Other that, doing some discussion with my supervisor and update the blog. Also doing some research to be placed in the report.

STUDY WEEK

WEEK 7

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

In this week, I'm construct the circuit and simulation of Class B audio amplifier using Multisim. For this circuit, I'm using 9V power supply and 8 ohm resistor to replace 8 ohm speaker. Doing this simulation not to difficult because I'm can get the result directly after construct the circuit and run the simulation.

This is Class B circuit using Multisim:

This is result (waveform) when I'm run the simulation:

Furthermore, I'm doing some discussion with my supervisor about my research and how to make this research successful. I'm also must about the calculation for getting the output power and speaker coil resistance that will be used. 

WEEK 6

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

For this week, I'm doing some discussion with my supervisor and buying all the component for Class B and AB audio amplifier. Other than that, I'm doing some research about IC TL082 that I will use in Class B audio amplifier.

IC TL082 (Absolute Maximum Ratings):

• Supply voltage: 18V
• Operating temperature range: 0 C + 70 C
• Tj (MAX): 150 C
• Storage temperature range: -65 C to + 150 C

Connection diagram:

Typical connection:

This devices are low cost, high speed, dual JFET input operational amplifiers with an internally trimmed input offset voltage. They require low supply current yet maintain a large gain bandwidth product and fast slew rate.

WEEK 5

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

In this week, after doing some discussion with my supervisor, I found the suitable circuit diagram for Class D audio amplifier. This Class D using the IC TDA7481. This IC is an audio class D amplifier assembled in Multiwatt 15 package specially designed for high efficiency applications mainly for TV and Home Stereo sets, capable of 18W power at load of 8w or 4w and a total harmonic distorsion of 10%. Requires a split-supply (max 20V).

The IC has build -in-stand-by and mute feature, overvoltage protection, short circuit protection and thermal overload protection.

Figure 8: schematic diagram

Figure 9: pinout - TDA7480

WEEK 4

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

In this week, I already found the suitable circuit diagram of Class AB audio amplifier. This audio amplifier which built using a TDA2002 or TDA2003 power amplifier IC module. It is easy to build and has a minimum of external components. 

Figure 7: Circuit diagram

Part and materials for Class AB audio amplifier:

• R1 - potentiometer 10kohm
• R2 - 220 ohm
• R3 - 2R2 ohm
• R4 - 1 ohm
• IC1 - TD2002/3
• Heat sinkC1 - 10uF/50V electrolytic capacitor
• C2 - 470uF/16V electrolytic capacitor
• C3 - 2200uF 25V electrolytic capacitor 1
• C4 - 100nF mylar 1
• C5 - 100nF monoblock 1
• C6 - 100uF 25V ecap 1

The module has both short circuit protection and thermal protection. It can drive loads as low as 1.6ohm and capable of delivering over 10 watts from a 16V supply.

WEEK 3

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

For this week, I already chosen the right circuit diagram for Class B amplifier. This circuit diagram is simple and not using many component.

Figure 5: Schematic diagram

Figure 6: Illustration

Part and materials for Class B audio amplifier:

• Four 6 volt batteries
• Dual operational amplifier, model TL082 
• One NPN power transistor in a TO-220 package
• One PNP power transistor in a TO-220 package
• One 1N914 switching diode
• One capacitor, 47uF electrolytic, 35WVDC
• Two capacitors, 0.22uF, non polarized
• One 10kohm potentiometer, linear taper

Be sure to use an op-amp that has a high slew rate. Avoid the LM741 or LM 1458 for this reason.

WEEK 2

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

In this week, I have to search and take the right circuit diagram for Class D and Class AB amplifier. other than that, I'm doing some discussion with my supervisor about circuit diagram and components that I will use and few things need to be considered before buying all the components.

This is some example of circuit diagram that I had found:

Figure 2: TDA8920BTH 200W Class D Amplifier

Figure 3: UM10155 Discrete Class D High Power Audio Amplifier

Figure 4: Class AB BJT 100W hi-end-audio

Last Thursday, 26 January 2012 at 3pm, there was a meeting with all FYP students at Gemilang Hall. The agenda is FYP updates and System Engineering. 

WEEK 1

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.


For the first week semester 1, 2012, I had a discussion with my supervisor on planning in this research for this semester. After discussion, I have come out with the Gantt Chart for this semester from week 1 until week 15. Figure show below is my Gantt Chart semester 2 FYP.

Gantt Chart S1'2012

On Tuesday, 17 January 2012 at 3pm, there was a meeting with all FYP students and Engineering Design students at Gemilang Hall. In meeting, the management of FYP want us to create a blog for our own project to replaced the logbook.

Logo of Blogger

So, all the information about the project including photos, videos and softcopy of full report must be upload in this blog. Other than that, all the FYP students degree sem 2 have to buy a t-shirt to be wear on Engineer Day in week 14.

INTRODUCTION

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

Amplifier plays an important role in an audio system. As it simply amplify the input audio signal to a certain power level to drive the speaker to bring the original desired signal to live. In recent market, Class AB amplifier seems to be dominating the audio market. Class B operation is opposite of Class A.

Figure 1: Class B, AB and D Amplifier

Class B amplifiers are those in which the output transistors only conduct during half (180 degrees) of the signal waveform. To amplify the entire signal, they use two transistors, one conducting for positive output signals and the other conducting for negative outputs. Class B amplifiers are much more efficient than Class A amplifiers, but they have high distortion due to the crossover point when the two transistors transition from on to off.

Class AB amplifiers combine Class A and Class B to form an amplifier with more efficiency than Class A but with lower distortion than Class B. This performance is achieved by biasing both transistors to conduct near zero signal output-the point where Class B amplifiers introduce nonlinearities. They then transistor to Class B for large excursions.

Class D amplifiers are those that output a switching waveform at a frequency for higher than the highest audio signal that needs to be reproduced. The lowpass-filtered, average value of this waveform corresponds to the actual required audio waveform. This amplifiers are highly efficient (often up to 90% or higher) because the output transistors are either fully turned on or off during operation. Modern Class D amplifiers achieve fidelity comparable to Class AB.

SYNOPSIS

Comparison Study of audio amplifier performances using Class AB, B and D topologies in portable audio devices.

In battery-powered portable audio devices such as mobile phones and MP3 playes, the audio amplifier takes a significant portion of the system's power budget. As a result, audio equipment  designers have been looking for enhancements to the Class AB topolology.

In this project, comparison studies such as power savings achievable through implementing a newer technology such as open looped Class D and Closed looped Class D against Ab and B will be performed. Differences in power consumption between different implementations of topologies should be studied to determine whether they are large enough to affect the overall power budget will also be performed. Besides the power consumption, other factors such as distortions and noise will be taken into account.

The student is expected to perform extension studies on various amplifier topologies, design, build and perform comparison between these topologies. Knowledge in analog electronics is an added advantage.