Op-Amp

理想的运算放大器

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库:
Simscape / Foundation Library / Electrical / Electrical Elements

描述

Op-Amp 模块对理想的运算放大器 (op-amp) 进行建模。下图显示了实现原理图。

Implementation schematic of the Op-Amp block

该模块的实现基于以下假设：

理想的运算放大器增益 A 假定为无限大
那么，对于有限输出，必须使 V1 = 0
理想的运算放大器还意味着电流从 p 到 n 为零 (i1 = 0)

这些假设得出该模块的以下方程：

equations
    v1 == p.v - n.v;
    v1 == 0;
    i1 == 0;
end

有关详细信息，请在模块对话框的描述选项卡中点击源代码链接。

该模块没有参数。但是，您可以在仿真之前初始化流入输出节点的电流变量。有关详细信息，请参阅Block-Level Variable Initialization。

变量

要在仿真之前设置模块变量的优先级和初始目标值，请使用模块对话框或属性检查器中的初始目标部分。有关详细信息，请参阅设置模块变量的优先级和初始目标值。

标称值提供了一种指定模型中变量的预期模的方法。使用基于标称值的系统缩放可提高仿真的稳健性。标称值可以来自不同的来源，其中之一是模块对话框或属性检查器中的的标称值部分。有关详细信息，请参阅Modify Nominal Values for a Block Variable。

示例

Band-Limited Op-Amp

How higher fidelity or more detailed component models can be built from the Foundation library blocks. The model implements a band-limited op-amp. It includes a first-order dynamic from inputs to outputs, and gives much faster simulation than if using a device-level equivalent circuit, which would normally include multiple transistors. This model also includes the effects of input and output impedance (Rin and Rout in the circuit), but does not include nonlinear effects such as slew-rate limiting.

打开模型

Finite-Gain Op-Amp

How higher fidelity or more detailed component models can be built from the Foundation library blocks. The Op-Amp block in the Foundation library models the ideal case whereby the gain is infinite, input impedance infinite, and output impedance zero. The Finite Gain Op-Amp block in this example has an open-loop gain of 1e5, input resistance of 100K ohms and output resistance of 10 ohms. As a result, the gain for this amplifier circuit is slightly lower than the gain that can be analytically calculated if the op-amp gain is assumed to be infinite.