| 摘要 |
<p>PURPOSE:To facilitate the formation of a semiconductor integrated circuit and to make it corresponding to an active filter circuit by constituting the negative feedback circuit of an operational amplifier of a variable conductance amplifier and an integrator composed of a capacitor connected to the output step. CONSTITUTION:An input terminal 1 is connected to the positive-phase-sequence input terminal of an operational amplifier A1, the output terminal is connected to an output terminal 2 and the positive-phase-sequence input terminal of a mutual conductance amplifier A2, a capacitor C1 is connected between the output terminal of the mutual conductance amplifier A2 and the ground and connected to the inverse-phase-sequence input terminal of the operational amplifier A1, and the mutual conductance amplifier A2 constitutes the integrator together with the capacitor C and operates as the negative feedback circuit of the operational amplifier A1. Then, a differentiated output is obtained from the output terminal 2. Therefore, the device is formed by the simple circuit and by adjusting the operating current of the variable conductance amplifier A2, the mutual conductance can be easily changed. Thus, the semiconductor integrated circuit can be easily formed and made fit for the active filter circuit.</p> |
