基于线性可调全差分OTA的电容倍增器

为了解决在集成电路中制作大容量电容器困难的问题,设计了一个线性可调跨导运算放大器(LO-TA),利用3个所设计的LOTA和1个接地电容实现了1个浮地电容倍增器.提出的电容倍增器能够通过调节相应LOTA的外部控制电流的比值实现电容容量的线性调节,调节范围为1～103倍时误差小于0.3%.电路的性能通过一个二阶电流模式滤波器和PSPICE仿真得到了验证.

Capacitance multiplier based on linearly tunable fully differential OTAs

In order to overcome the difficulty in fabricating large capacitors in integrated circuits,a Linearly tunable Operational Transconductance Amplifier (LOTA) is designed at first,and then a floating capacitance multiplier circuit composed by the three LOTAs and a grounded capacitor is achieved.The capacitance of the proposed capacitance multiplier can be linearly tuned in 1~3 orders of magnitude through the external control currents’ ratio of the corresponding LOTAs with less than 0.3% error.The performance of the proposed capacitance multiplier is discussed and confirmed through an application example and PSPICE simulation results.