Design Of A Continuously Adjustable Class D Power Amplifier

The Power amplifier is one of the core components of the sonar transmitter. Regarding its special application environment in sonar transmitter, the amplifier circuit must have small size,low power consumption,high efficiency,high reliability and output power adjustment.The main job of this thesis is to design a continuously adjustable Class D power amplifier. At first, the classification of the power amplifier is discussed. According to the requirements, class D power amplifier is chosen as the main design. Then the proposed amplifier technical indicators are indicated, and the design of the power control part is determined. Switching power supply is used in the amplifier circuit, so the composition and classification of switching power supply topologies are discussed. And the structure of the switching power supply is determined. Besides,the transformer and power MOSFET are also integral parts for both the amplifier and switching power supply, so the model of the power MOSFET is introduced. And the design of transformers is explained.Functions of the power control circuit and the amplifier circuit are illustrated respectively. Models and parameters of required circuit components are listed. And parameters of the transformers are calculated and determined.Finally, debugging of the power supply part and the amplifier part are carried out separately. And then the whole circuit is tested and the results are analyzed. The results show that the whole circuit works well, and all specifications satisfy the design requirements.