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一、前言 在许多测量和控制系统中,通常用集成运放对微弱的电信号进行放大和处理,集成运放的精度将直接影响测量系统的精确度。 影响集成运放精度的因素是多种多样的,但是在不同的使用条件下将由不同因素起主导作用。例如,在同相放大器中,集成运放的同相端和反相端差不多等于输入电压,即加有共模电压,因此,同相工作的运算放大器应具有良好的共模抑制比和较宽的共模电压工作范围;而在反相放大器中,同相端和反相端电压几乎为零,即共模输入电压几乎为零,此时共模电压不是主要因素,但是,失调电压引入的误差将起主要作用。由图1
I. INTRODUCTION In many measurement and control systems, it is common to amplify and process weak electrical signals using an integrated operational amplifier. The accuracy of the integrated operational amplifier will directly affect the accuracy of the measurement system. The factors that affect the accuracy of the integrated op amp are varied, but under different conditions of use will be dominated by different factors. For example, in a noninverting amplifier, the integrated op amp’s non-inverting and inverting terminals are almost equal to the input voltage plus a common-mode voltage, so op-amps operating in the same phase should have good common mode rejection and wider common mode Voltage operating range; In the inverting amplifier, the non-inverting and inverting terminal voltage is almost zero, that is common mode input voltage is almost zero, the common mode voltage is not a major factor, but the error introduced by the offset voltage will play a major effect. From Figure 1