| 摘要 |
<p>Provided is a variable gain amplifier. The variable gain amplifier includes an operational amplifier, a variable feedback impedance unit, a variable compensation impedance unit, and a variable current source. The variable feedback impedance unit is connected between an inverting input terminal and output terminal of the operational amplifier, and has a feedback impedance value which varies for gain control. The variable compensation impedance unit is connected to the inverting input terminal, and has a compensation impedance value which varies in response to change of the feedback impedance value for maintaining a constant feedback factor. The variable current source is connected to the inverting input terminal, and supplies an output current, which varies in response to change of the compensation impedance value, to the variable compensation impedance unit.</p> |
