Over the last several decades, there have been studied many amplifiers for the consumer electronics which are so familiar with human````s life. Amplifiers in electronics are used in a wide variety of applications in the areas of audio, TV, personal computer application and so on. A conventional analog amplifiers such as class A, class B and class AB based on the linear circuit technology, have very excellent distortion characteristics, but show considerably poor power efficiency and bulky volume for cooling. On the other hand, the class D digital switching amplifier, which adopts a pulse width modulation (PWM) technology, has high efficiency and small volume but relatively bad fidelity.
This thesis presents analog / digital switching mixed mode amplifiers (MMA) and their applications for audio, regulator and TV. The proposed amplifier named MMA, more simply class k amplifier, simultaneously has only the advantages of conventional amplifiers, which are high fidelity (or low total harmonic distortion: THD) and high efficiency. It is composed of two amplifier circuits: one is analog amplifier and the other is digital amplifier. Analog amplifier plays a role of independent voltage source, which is responsible for high fidelity. On the other hand, digital amplifier works as a dependent current source, which is in charge of high efficiency. Digital amplifier supplies almost all the current needed in load, but analog amplifier merely supplies the rest of current, i.e., ripple current to compensate the distortion caused by the digital amplifier. In order to verify the operation principle as well as usefulness of MMA in commercial applications, the four kinds of prototypes, i.e., two kinds of audio power amplifiers, one regulator and one vertical deflection amplifier are implemented for the practical commercial applications.
A novel mixed mode amplifier for high fidelity and high efficiency audio application is presented. To confirm the operation for audio application...