基于开关信号理论的电流型CMOS多值施密特电路设计

以开关信号理论为指导,建立了描述电流型CMOS多值施密特电路中阈值控制电路的电流传输开关运算.在此基础上,提出了新的电流型CMOS三值和四值施密特触发器设计.所设计的电路可提供多值电流和电压输出信号,回差电流的大小只需通过改变MOS管的尺寸比来调节.所提出的电路较之以往设计具有结构简单,回差值调整容易以及可在较低电压下工作等特点.采用TSMC 0.25 μ m CMOS工艺参数和1.5V电压的HSPICE模拟结果验证了所提出设计方案的有效性和电路所具有的理想回差特性.

Design of Current-Mode CMOS Multiple-Valued Schmitt Triggers Based on Switch-Signal Theory

Guided by the switch-signal theory, the operations of current transmission switch used to describe the action of threshold-controUable switch in multiple-valued Schmitt trigger were established, and novel current-mode CMOS ternary and quaternary Schmitt triggers with output current and voltage signal were presented. The hysteresis current values of multiple-valued Schmitt triggers were controlled by only sizing the transistor aspect ratios. The main properties of the circuit are its simple structure, fully adjustable hysteresis and suitable for low-voltage applications. The designed circuits are simulated using HSPICE program and the model parameters of a TSMC 0. 251xm CMOS process, with 1.5V power supply. From the simulation results, the effectiveness of the proposed approach and the ideal character- istic of multiple-valued Schmitt circuit are validated.