【摘要】 针对开关电容采样/保持(S/H)电路中由负载电容记忆效应引起的电荷共享问题进行了建模.电荷共享效应会导致运放建立幅度增加,根据所推导的运放建立总公式,得出建立幅度增加会增大对运放功耗和带宽要求,或者降低建立速度.为改善该现象,基于预充电思想和双采样技术提出了一种优化方案,能在保持原S/H电路速度不变时,消除电荷共享效应对运放功耗和带宽的额外要求.仿真实现的12位100Msps双采样/保持电路证明了其有效性.更多还原

【Abstract】 Charge sharing phenomenon due to load capacitance’s memory effect in switched-capacitor sample-and-hold(S/H) circuit is modeled,which gives it may cause the opamp settling amplitude increasing.According to the total equation derived from the settling behavior of opamp,the increased amplitude may further cause more power,larger bandwidth or lower speed.For improving this phenomenon,an optimizing methodology is proposed based on pre-discharge theory and double sampling technology,which can eliminate the extra requirement of power and bandwidth without reducing the initial speed of S/H circuit.A 12bit,100Msps double S/H circuit achieved by simulation proves the availability of this method.更多还原