下截止频率1.3～244 Hz可调带通VGA设计

发布时间：2019-03-07 17:23

【摘要】：采用电压控制的伪电阻结构,设计了一款具有超低频下截止频率调节功能的带通可变增益放大器(VGA),由于该结构具有可调节超大的等效电阻和反馈电容使VGA的下截止频率可以调节。提出了一种改进的甲乙类运算跨导放大器(OTA)结构,采用新颖的浮动偏置设计,在满足高压摆率的条件下,有效提高共源共栅结构的电压输出范围。将伪电阻用于OTA的共模反馈,克服了阻性共模检测结构负载效应的问题。该VGA电路采用TSMC 0.18μm标准工艺设计和流片,测试结果表明,1.2 V电源电压下,其下截止频率调节范围为1.3~244 Hz,增益为49.2,44.2,39.2 d B,带宽为3.4,3.9,4.4 k Hz,消耗电流为3.9μA,共模抑制比达75.2 d B。
[Abstract]:A band-pass variable gain amplifier (VGA) with an ultra-low-frequency lower-cut-off frequency adjustment function is designed by means of a voltage-controlled pseudo-resistance structure, since the structure has an adjustable large equivalent resistance and a feedback capacitor so that the lower cut-off frequency of the VGA can be adjusted. A modified class B operational transconductance amplifier (OTA) structure is proposed, and a novel floating bias design is used to effectively improve the voltage output range of the cascode structure under the condition of high slew rate. The pseudo-resistance is used for common mode feedback of the OTA, and the problem of the load effect of the resistive common mode detection structure is overcome. The test results show that the lower cut-off frequency of the VGA circuit is 1.3-244Hz, the gain is 49.2, 44.2, 39.2 d B, the bandwidth is 3.4, 3.9, 4.4k Hz, the consumption current is 3.9. m A, and the common-mode rejection ratio is 75.2 d B.
【作者单位】：中国科学院上海高等研究院;中国科学院大学;上海科技大学;
【分类号】：TN722

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