摘要
针对传统开关消抖电路对开关波动现象处理能力不足的情况,利用运算放大器的高增益特点,在运放的输出端与同相输入端之间引入正反馈电阻构成一个滞回比较器,比较器的反相输入端在机械开关闭合的瞬间连接已充足电的电容,反相端电压(即电容电压)的绝对值大于相对应的阈值电压绝对值,输出电压反转;由于开关闭合以后电容的充电电压最大只有0.01倍供电电压,加上电容充电时间远远大于机械抖动脉冲周期,故机械开关的波动不可能引起运放输出的反转,只有再一次闭合开关才可以引起输出电平逻辑值变化,圆满实现了消除开关抖动的目的。
In view of the insufficient ability of traditional switching dithering circuit to deal with switching fluctuations,for beneficial to the high gain characteristics of operational amplifiers,a hysteretic comparator is constructed by introducing a positive feedback resistance between the output end of the amplifier and the input end of the same phase.The inverse input end of the comparator is fully charged when the mechanical switch closes.The absolute value of capacitance,inversion terminal voltage(capacitance voltage)is greater than the corresponding threshold voltage,and the output voltage is inverted.Since the maximum charging voltage of capacitor is only 0.01 times of the supply voltage after the switch is closed,and the charging time of capacitor is much longer than the period of mechanical dithering impulse,the fluctuation of mechanical switch can not be induced.Only by closing the switch again can the logic value of the output level be changed and the switching jitter can be eliminated satisfactorily.
作者
崔建国
宁永香
Cui Jianguo;Ning Yongxiang(Shanxi Engineering and Technology College, Yangquan Shanxi 045000, China)
出处
《山西电子技术》
2020年第2期7-9,共3页
Shanxi Electronic Technology
关键词
正反馈
滞回比较器
触发
抖动
阈值
positive feedback
hysteretic comparator
trigger
jitter
threshold
