毕业设计实例批注.docVIP

济南大学泉城学院 毕业设计 题 目 学 院 专 业 班 级 学 生 学 号 指导教师 二〇一六年月日摘 要 本次主要目的是设计一个由集成运放与分立元件构成的音频放大器，实现对输入的微弱电信号进行放大，输出功率为10W的音频信号，达到驱动扬声器（负载）发声的目的。在设计中前置放大电路选用的是双电源、低噪声的NE5532集成运算放大器，可以完成小信号的电压放大作用，电压范围在±3V~±22V之间，所以采用±12V供电。分立元件构成的双电源供电的OCL互补推挽功率放大电路应用于功率放大后级，由于电路性能更好，因此它被广泛地应用在高保真音响设备，它主要由输入级、中间级和输出级三部分组成，主要完成电流的放大。输入级是一个偏置电路，主要提供电路的偏置电压，消除电路的交越失真，中间级是一个达林顿连接电路，主要是为了增大电流的放大倍数，输出级采用的是推挽式的OCL互补电路，能控制输出的大电流，这样使得输出电阻较小，带负载能力增强。因为前级和后级都是双电源供电，所以设计的直流稳压电路需要输出正、负两路电压。整个电源电路由降压、整流、滤波和稳压四部分组成，NE5532需要±12V的电压，所以选用的是型号为LM7812与LM7912的三端稳压器。输入的市电在经过整流滤波电路，输出±17V的电压，给功率放大电路使用，然后在经组成的稳压电路之后，输出±12V的电压，给前置放大电路使用。本次设计较严谨地处理各个环节衔接和设计，能较好的达到音频传输的效果，利用分立元件和集成元件设计电路有其使用价值和研究价值[1]。 关键词：集成运算放大器；前置放大；功率放大 ABSTRACT The main purpose is to design an audio amplifier which is composed of integrated operational amplifier with discrete components, implementation of the weak input electrical signal amplification and which the output power of 10W of audio signals, to achieve drive the loudspeaker (load) to sound. In the design of preamplifier circuit used is double power supply, low noise of NE5532 integrated operational amplifier, which can be complete the small signal voltage amplification, the voltage range between ±?3V~?±?22V, so the ±?12V?power supply is used. The discrete components of the dual power supply OCL complementary push-pull power amplifier circuit is applied to the power amplifier stage, due to better performance of the circuit, so it’s widely used in Hi-Fi audio equipment, it is mainly composed of three parts of input stage, intermediate stage and output stage, which mainly to complete the current amplification. The input stage is a bias circuit, the mainly to provide a bias voltage of the circuit and to eliminate the circuit of crossover distortion, intermediate stage is a Darlington connection circuit, mainly to increase the magnification of the current, the output stage is a push-pull OCL complementary