基于线性可调全差分OTA的电容倍增器

Capacitance multiplier based on linearly tunable fully differential OTAs

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.

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.