Introduction to the best audio amplifier design

An audio amplifier is an amplifier that increases smaller audio signals while maintaining the smaller details of the signal. The demands of today's audio industry have increased the architecture of audio amplifiers. The types of audio amplifiers available in the market and the specifications associated with them can help make the best choice of audio amplifier integrated circuit for a specific application.

introduce

An audio amplifier increases the amplitude of a small signal to a useful level while always maintaining the detail of the small signal. This is called linearity. The greater the amplifier linearity, the more the output signal is a true representation of the input.

As the audio market continues to change amplifier performance requirements, there have been many advances in audio amplifier topologies. Therefore, designers must know the types of audio amplifiers available and the characteristics associated with each amplifier. This is the only way to ensure that you choose the best audio amplifier for your application. In this tutorial, we will look at the most important characteristics of each audio amplifier available today: Class A, Class B, Class AB, Class D, Class G, Class DG, and Class H.

Class A amplifier

The simplest type of audio amplifier is Class A. The output transistors of a Class A amplifier (Figure 1) conduct (i.e., are not completely off) regardless of the output signal waveform. Class A is the most linear audio amplifier, but has low efficiency. Therefore, these amplifiers are used in applications that require high linearity with sufficient power.

Class A audio amplifiers generally have higher linearity but lower efficiency

Class B Amplifier

Class B amplifiers use a push-pull amplifier topology. The output of a Class B amplifier contains a positive and negative transistor. To replicate the input, each transistor conducts only during half (180°) of the signal waveform (Figure 2). This allows the amplifier to idle at zero current, improving efficiency compared to a Class A amplifier.

Class B amplifiers come with a trade-off: increased efficiency comes at the expense of audio quality. This happens because there is a crossover point where the two transistors transition from the on state to the off state. Class B audio amplifiers are known to produce crossover distortion when processing low-level signals. They are not a good choice for low-power applications.

With a Class B audio amplifier, the output transistor conducts only during half (180°) of the signal waveform. To amplify the entire signal, two transistors are used, one transistor conducting the positive output signal and the other conducting the negative output signal.

This is a brief survey of the many types of audio amplifiers commonly used in today's designs. Obviously, when designing an audio circuit for any type of equipment, care should be taken to determine the audio amplifier topology that is best suited for the application. A good understanding of these different categories of audio amplifiers will help you choose the best audio amplifier for your design.