基于TL494器件反馈控制的Buck降压电路的设计

Design of Buck Circuit Based on TL494 Feedback Control

Buck电路,也称降压电路,是一种输出电压小于输入电压的直流到直流的变换电路。传统的Buck电路是基于开环控制的电路,而本文分析基于一种反馈器件TL494对Buck电路进行闭环控制的设计,其中输出电压反馈到TL494芯片的一个引脚,通过内部比较电路将其与基准电压比较后产生PWM(脉冲宽度调制)信号来推动MOSFET(半导体场效应晶体管)的开断,最终得到确定纹波比的稳定的电压。

Buck circuit, it is the DC to DC conversion circuit whose output voltage is less than tne input voltage. The traditional Buck circuit is based on open loop control circuit. However, in this paper, we analyze the design of dosed loop control of Buck circuit based on a feedback chip TL494.In it, the output voltage is fed back a pin of TL494,after comparison between the output voltage and the reference voltage by the internal comparison circuit,it produces a PWM signal to drive MOSFET to turn on or off. At last, we get the stable voltage whose Bobbi is certain.