基于TL494的直流变换器

DC-DC Converter based on the TL494

文章介绍了开关电源的基本原理,DC/DC变换主电路分类,对开关电源的控制方式进行了比较,给出了专用集成控制器的优点。给出了专用集成控制器TL494的内部结构、管脚功能,详细分析了其工作原理、应用和优点,列举了TL494的应用实例。设计了一款由TL494控制的Buck型开关电源,给出了所用元器件,对整个电路工作原理进行了分析,分析了其产生PWM信号的原理,接收反馈实现稳压的原理及实现过流保护原理,测试其关键点的工作波形,并对此电路做了些改进,基于此对TL494进行了测试,该电路是TL494的典型应用,可以体现出TL494的大部分功能,电路具有采用元件少、性能稳定、效率高的优点。

This article describes the basic principles of switching power supply,the main circuit classification of DC/DC converter and control methods were compared,given the advantages of a dedicated integrated controller; given TL494＇s internal structure,pin function,a detailed analysis of its working principle,application and its merits and the application examples listed;designed a buck converter controlled by the TL494,given the components used,the working principle of the whole circuit is analyzed,analyzes the principle of generate PWM signal,the principle of feedback to achieve regulation and achieve over-current protection,test the work of its key waveforms,and made some improvements to this circuit,and based on the circuit test TL494;the circuit is the typical applications of TL494,can reflect most of TL494 features,the circuit has fewer components used,stable performance,high efficiency.