摘要
本文提出一种适用于恒定导通时间控制的开启时间定时器电路。电路中采用与输入电源电压成正比的电流对电容充电,从而实现定时器的定时时间与输入电源电压成反比,解决了传统恒定导通时间控制中系统工作频率随输入电源电压变化的问题。为了获得高的定时精度,开启时间定时器中的比较器采用了自适应偏置技术,根据输入电源电压的情况动态地设置定时器中比较器的偏置电流。基于0.6μmCD工艺,对所设计开启时间定时器电路进行仿真验证。结果表明,本文所设计的开启时间定时器电路,能够始终保证高的定时精度。同时由于定时时间与输入电源电压成反比,在系统中引入了前馈,极大地提高了系统的线性响应速度。
A kind of on timer circuit applicable to constant on-time mode control was put forward in this paper.ln the circuit the current that proportional to the input voltage charge the capacitance,so as to realize the timing of time is inversely proportional to the input voltage,which can solve the working frequency change with input voltage in the traditional constant on-time mode control.In order to get high precision timer,the comparator in timer is used the adaptive biasing technology which can dynamic set the bias current of comparator according to the input vohage. on_timer circuit is simulated and verified on the 0.6urn 16V CD process.The results show that the on_timer in this paper can always guarantee the high precision timing.Because input voltage,so a feedforward path is introduced into the system speed. of the timing of time is inversely proportional to the which can greatly improve the system linear response
出处
《中国集成电路》
2012年第9期40-44,共5页
China lntegrated Circuit
