一种基于迟滞比较器的锯齿波产生电路

A sawtooth wave generation circuit based on hysteresis comparator

介绍一种基于TSMC 0.18μm工艺设计的锯齿波产生电路。传统锯齿波产生电路通常以比较器为核心结构,采用恒流源充放电技术实现。为了获得更快的响应速度,设计了一款利用内部正反馈原理实现的迟滞比较器来取代传统比较器,同时改进架构,得到一种对电源电压变化不敏感,具有较高频率的锯齿波产生电路。最终通过HSpice对电路进行了仿真验证,在常温下锯齿波的频率大约为7.5 MHz;同时当电源电压在2.5~4.5 V内变化时,锯齿波的频率变化不超过0.12 MHz。

A sawtooth wave generation circuit designed with TSMC 0.18 μm process is introduced. The traditional sawtooth wave generation circuit often takes the comparator as its core structure and is realized with the constant current source chargingdischarging technology. To obtain faster response,a hysteresis comparator based on the internal positive feedback principle is designed to take place of the traditional comparator. The architecture is improved to obtain a high frequency sawtooth wave generation circuit insensitive to power supply voltage changes. The circuit was simulated and verified by HSPICE. The results show that the frequency of sawtooth wave at room temperature is about 7.5 MHz,and the frequency change is not more than 0.12 MHz when the power supply voltage changes from 2.5 V to 4.5 V.