基于555定时器的高线性度锯齿波发生器

文中简要分析了用555时基电路构成锯齿波发生器的基本原理，指出构成线性度良好的锯齿波发生器所需要满足的关键条件即以一恒定的电流对定时电容进行充电并以极快的速度放电。考虑到可以采取不同的电路来实现恒流充电，提出了构成线性度良好的锯齿波发生器的3种具体方法：自举式、恒流源式、电压一频率转换式。并分析了各种锯齿波发生器的特点，给出各自产生的锯齿波的频率的计算公式。通过实验证明，这几种方法得到的锯齿波的线性度良好。

Well Linearity Sawtooth Wave Generator Based on 555 Timer

The basic principle of the sawtooth-wave generator which designed by the 555 timer was analyzed briefly.The key condition that the timed capacitor must charged by constant current and discharge quickly to the well linearity sawtooth-wave generator was pointed out.In consideration of different circuit can provide constant current,three kinds of concrete methods which can generate well linearity sawtooth-wave have been put forward:bootstrap type,constant current source type,and voltage-current converter type.And their respective characteristic was analyzed,the formula to calculate the frequency of the sawtooth wave which generated by these methods was pointed out.The sawtooth wave which generated by these methods has well linearity,this was demonstrated by the experiments.