目前D类音频功率放大器具有成本低、效率高、音响效果好的特点,同时还存在着很多的缺点,如失真度大,不易调试等一些需要改进的地方.
The current class D audio power amplifier is characterized with low cost,high efficiency and good sound effects,as well as a lot of disadvantages,such as high distortion and difficult debugging/adjustment,which need to be improved.
本设计的原理是D类功放是放大元件处于开关状态时的一种放大模式.
The principle of this design is to make/keep the amplifying element of class D power amplifier in the amplification mode when switch is on.
无信号输入时放大器处于静止状态,不耗电.工作时,打开开关,接通电源,接入音频输入,产生音频信号,和运放产生的三角波信号同时通过比较器,通过比较产生PWM调制波信号,再通过死区保护进入LC低通滤波器,过滤成音频信号经过放大后输入扬声器,放出声音.
When there is no signal input,the amplifier is in the off state with no power consumption.When the power switch is turned on and the audio input is connected,the amplifier is in working state,the signals transmitted by audio input pass through the comparator simultaneously with the triangle wave signals generated by OPAMP,and by comparing the two,it generates PWM modulated wave signal which,with the protection of the dead zone,enter the LC low-pass filter,filtrated into audio signals,and transmitted into speaker via amplifier to produce sound.
采用运放芯片OP07组成三角波产生电路,比较器采用LM393N.
The OPAMP chip OP07 is used to form a triangular wave for generating circuit,and the LM393N is used for comparator.
最后通过硬件电路进行系统的调试,实现了系统的整个功能.
Finally,the system is adjusted via hardware circuit to achieve the complete function of the system.