“Spinal cord stimulation (SCS)” is an established therapy for chronic pain and an emerging modality for functional recovery after spinal cord injury (SCI) and other clinical applications. Despite its clinical potential, current implantable SCS systems remain constrained by high power consumption, limited adaptability, device size, and long-term stability. Recent advances in closed-loop neuromodulation and integrated circuit (IC) design are enabling more adaptive, efficient, and miniaturized SCS systems. This narrative review focuses on integrated circuit and system-on-chip (SoC) architectures that enable more advanced closed-loop SCS modalities, including stimulation, sensing, and wireless power/data subsystems. Specifically, the present work examines stimulation drivers and charge-balancing circuits that ensure safe and precise current delivery, wireless power transfer, telemetry methods which maintain reliable energy and data flow in implanted systems, and analog front-end circuits that enable closed-loop biopotential monitoring for adaptive feedback control. It aims to highlight innovations in IC design, energy harvesting, and wireless communication strategies while discussing trade-offs in power efficiency, die area, thermal limits, and biocompatibility. Emerging trends emphasize miniaturized and adaptive neural implants that integrate circuit-level efficiency with therapeutic flexibility, thereby advancing the next generation of closed-loop neuromodulation technologies. Ultimately, innovations in microelectronics are paving the way for enhanced long-term efficacy, safety, and clinical applicability of implantable SCS systems to optimize functional impacts.