D类功放输出功率调节电路设计

Design of Class D Power Amplifier with Output Power Adjustment

D类音频功放具有高效率的优点,但是随着功率的不断提高,通常需要完善的保护及限制电路。设计介绍了一种用于高功率D类音频功率放大器的输出功率调节电路,可以通过芯片外部引脚输入电压或编程的方式动态调节功放的输出功率。控制方式采用了限制输入信号最大幅度的方法,分别介绍了电路的控制原理与电路实现。测试结果显示,该电路达到了较好的调节效果,具有好的调节线性度,提高了高功率放大器电路的可靠性。

Because the class D audio power ampliifer has the advantages of high efifciency, has become the trend of the development of high-power audio ampliifer, but with the constant improvement of the power, the reliability of the system is particularly important, often need to perfect protection and limiting circuit. The paper introduces a design for high power class D audio power ampliifer output power regulating circuit, can be done by outside chip pins input voltage or programmatically dynamically adjust the output power of the power ampliifer. Control method using the method of the biggest limit input signal respectively introduces the control principle and circuit realization of the circuit. Test results show that the circuit has reached the good adjustment effect has good linearity adjustment, improve the reliability of the high power ampliifer circuit.