Design and characterization of CMOS differential pair circuits for membership function generation with noise analysis in fuzzy logic systems

With the growing demand for energy-efficient and sustainable electronic systems,CMOS technology plays a crucial role in ad vancing green electronics and greentechnologies, emerging as a key enabler for low-power analog hardwareimplementations in intelligent systems. This paper presents a comprehensive study ofCMOS differential pair implementations for generating bell shaped and sigmoidmembership functions, which serve as fundamental components in fuzzy logicsystems, directly influencing decision-making accuracy. By employing CMOSdifferential pair circuits, we propose a hardware-efficient approach to realize smooth,continuous, analog membership functions suitable for fuzzy inference applications. Thestudy encompasses detailed mathematical modeling, circuit design methodologies,and performance evaluation through LTspice simulations. Particular em phasis isplaced on noise characterization, where both flicker (1/f) noise and thermal noisecontributions are analyzed to assess their impact on circuit performance. The resultsdemonstrate how circuit topology and membership function shape affect noisebehavior, supported by a comparative analysis of bell-shaped and sigmoid functionimplementations. Additionally, the characteristic curves of both membership functionsare extracted and discussed, validating their operational suitability for analog fuzzylogic systems. The findings provide valuable insights for designing low-noise, analogfuzzy inference hardware, thereby contributing to enhanced reliability, precision, andenergy efficiency in intelligent electronic systems.