Innovative Design Approaches with Self-Adaptive Methods for Analog and RF Circuits

Abstract

In analog and radio frequency (RF) circuit design, innovation is a cornerstone driving progress amid escalating demands for energy efficiency, reliability, and performance optimization. This thesis, titled ”Innovative Design Approaches with Self-Adaptive Methods for Analog and RF Circuits,” presents a comprehensive exploration of cutting-edge methodologies to revolutionize circuit design paradigms. Divided into two distinct yet interconnected sections, the thesis embarks on a journey through the intricate landscape of analog and RF circuitry. The first section delves into the intricate art of low-power analog and RF design, driven by the relentless pursuit of energy efficiency. Here, novel architectures, circuit topologies, and optimization techniques have been explored to minimize power consumption while preserving signal integrity and performance metrics. The journey begins with a meticulous investigation into two low-supply 0.5V current/voltage reference designs tailored for ultra-low power IoT and biomedical applications. The first one, designed in CMOS 90nm technology, proposes a current and voltage reference that achieves a typical accuracy of 34.6ppm/◦C (29.68ppm/ ◦C) over a wide temperature range of -55◦C to 75◦C with typical value 63.32pA(0.35V). We observe excellent line sensitivities of 0.0318%/V and 0.0576%/V for voltage and current references in a supply range of 0.5V - 2.3V. The second reference focuses on reducing the power to half compared to the previous one. The design generates reference values of 90.7pA and 288mV, giving an excellent temperature coefficient of 15.2ppm/°C and 36.8ppm/°C for compensated current and voltage values, respectively, at a nominal supply of 0.5V for a wide temperature range of -55°C to 100°C. The circuit works for a wide voltage range of 0.5V - 2.6V with a supply sensitivity of 0.028%/V and 0.154%/V for current and voltage reference, respectively. The thesis then introduces a new nW range gate-leakage-based Sub-Bandgap Voltage Reference (SUB-BGR) for low-power, high-temperature IoT applications. Designed in TSMC 65nm technology, the proposed architecture achieves an accuracy of 94ppm/◦C. It achieves an excellent line sensitivity of 0.0066%/V for a supply range of 0.7V to 4V and PSRR of 89dB at DC 1V supply. As the spectrum broadens, the focus shifts to the high-frequency domain, where the work explores the intricacies of on-chip Vector Network Analyzers (VNAs). It introduces a fully integrated low-power, low-area on-chip single-port CMOS VNA, designed explicitly for bio-molecule detection, operating in a tunable frequency range of 0.5GHz to 2.5GHz. This design incorporates innovative features such as an IDC sensor and a high-linearity Low Noise Amplifier (LNA), demonstrating superior performance metrics within a compact footprint. The process, voltage, and temperature (PVT) variations immensely affect the circuit performance of the Analog and RF circuits. The second section of the thesis delves into self-adaptive methodologies tailored to mitigate variations across PVT, addressing the challenge of ensuring consistent circuit performance. Leveraging adaptive control and feedback mechanisms, self-adaptive loops are developed and implemented in simulation, dynamically adjusting circuit parameters in real-time. For efficient self-adaptation, the information of P, V, and T is necessary to provide accurate real-time feedback, enabling dynamic parameter adjustments in analog and RF circuits. This thesis significantly contributes to the advancement of analog and RF circuit design methodologies through a synthesis of theoretical analyses, simulation studies, and practical implementations. By embracing innovation and harnessing the power of self-adaptive methods, this research paves the way for a new era of agile, efficient, and resilient analog and RF circuits.