This paper proposes a modified version of recycling folded cascode amplifier. A comparative study, modelling and analysis of the proposed design along with conventional folded cascode and recycling folded cascode have been presented in this work. The design is intended for use as a preamplifier in an epileptic neurostimulator circuit, which ensures high gain, low noise low power trade-off and smaller bandwidth (lower than 500 Hz) as the primary criteria. An adaptive biasing technique is implemented to enhance the key performance parameters like intrinsic gain, slew rate and gain-bandwidth product. Also, the proposed device works in weak inversion region to ensure ultra-low power consumption. There are various neurostimulators categorized as Deep Brain Stimulation and Vagus Nerve Stimulation reported in the literature so far. However the proposed design considers high-frequency oscillations (HFO) as the biomarker of focal epileptic seizures, owing to its occurrence in higher frequencies, thereby asserting a bandwidth less than 500 Hz. The simulations for the designed structures are carried out in Cadence Virtuoso using SCL 180 nm technology, with an operating voltage 0.6 V. The simulation results illustrate the improvement in several parameters: intrinsic DC gain by 14 dB with a consumed power of 1.782 µW, and an input-referred noise of 10.97 µV/√Hz @1 Hz, establishing that the design works with ultra-low power consumption. Analytical modelling and comparative analysis of the proposed as well as conventional designs have been performed. Additionally comparison has been drawn between the pre-layout and post layout simulation results which shows close matching between each other. Furthermore, Monte Carlo analysis has been performed on the proposed design to validate its consistency and dependability.

本文提出了一种改进型的循环折叠共源共栅放大器。在这项工作中，已经对建议的设计以及常规折叠共源共栅和回收折叠共源共栅进行了比较研究，建模和分析。该设计旨在用作癫痫神经刺激器电路中的前置放大器，以确保高增益，低噪声，低功率折衷和较小的带宽（低于500 Hz）为主要标准。实施了自适应偏置技术，以增强关键性能参数，例如固有增益，转换速率和增益带宽积。此外，该器件可在弱反相区域工作，以确保超低功耗。迄今为止，已有文献报道了各种神经刺激器，分别归类为深部脑刺激和迷走神经刺激。但是，由于高频振荡（HFO）发生在较高的频率中，因此提出的设计将高频振荡（HFO）视为局灶性癫痫发作的生物标记，从而断定带宽小于500 Hz。使用SCL 180 nm技术在Cadence Virtuoso中对设计的结构进行了仿真，工作电压为0.6V。仿真结果说明了以下几个参数的改进：固有DC增益为14 dB，消耗功率为1.782 µW，以及输入参考噪声为10.97 µV /√Hz@ 1 Hz，从而证明该设计工作于超低功耗状态。已对建议的设计和常规设计进行了分析建模和比较分析。另外，在布局前和布局后仿真结果之间进行了比较，显示出彼此之间的紧密匹配。此外，已经对提出的设计进行了蒙特卡洛分析，以验证其一致性和可靠性。