Design of a Power Management Circuit for an Opto-Electro Stimulator

This paper presents the design of an integrated power management circuit for use in an implantable opto-electro stimulator. It features an active rectifier with pulse width modulation (PWM) regulation to generate a 3.3 V regulated output, and a 3-stage high voltage charge pump (CP) that generates a 12 V output from a 3.3 V input with a 20 MHz, two-phase non-overlapping clock generator. The circuits were designed in a 0.18-µm CMOS technology requiring a chip area of 0.048 mm 2 . Simulation results show that the regulating rectifier has a voltage conversion efficiency of 94.3% and 92.8% with an ac input magnitude of 3.5 V and 3.6 V, respectively. The peak power transfer efficiency of the regulated 3.3V output voltage is 70.7% with a maximum output power of 30.3 mW. The CP with an overall on-chip capacitance is 60 pF

In-Body Energy Harvesting Power Management Interface for Post Heart Transplantation Monitoring

Deep tissue energy harvesters are of increasing interest in the development of battery-less implantable devices. This paper presents a fully integrated ultra-low quiescent power management interface. It has power optimization and impedance matching between a piezoelectric energy harvester and the functional load that could be potentially powered by the heart's mechanical motions. The circuit has been designed in 0.18-µm CMOS technology. It dissipates 189.8 nW providing two voltage outputs of 1.4 V and 4.2 V. The simulation results show an output power 8.2x times of an ideal full-bridge rectifier without an external power supply. The design has the potential for use in self-powered heart implantable devices as it is capable providing stable output voltages from a cold startup

Efficient Dual Output Regulating Rectifier and Adiabatic Charge Pump for Biomedical Applications Employing Wireless Power Transfer †

A power management unit (PMU) is an essential block for diversified multi-functional low-power Internet of Things (IoT) and biomedical electronics. This paper includes a theoretical analysis of a high current, single-stage ac-dc, reconfigurable, dual output, regulating rectifier consisting of pulse width modulation (PWM) and pulse frequency modulation (PFM). The regulating rectifier provides two independently regulated supply voltages of 1.8 V and 3.3 V from an input ac voltage. The PFM control feedback consists of feedback-driven regulation to adjust the driving frequency of the power transistors through adaptive buffers in the active rectifier. The PWM/PFM mode control provides a feedback loop to adjust the conduction duration accurately and minimize power losses. The design also includes an adiabatic charge pump (CP) to provide a higher voltage level. The adiabatic CP consists of latch-up and power-saving topologies to enhance its power efficiency. Simulation results show that the dual regulating rectifier has 94.3% voltage conversion efficiency with an ac input magnitude of 3.5 Vp. The power conversion efficiency of the regulated 3.3 V output voltage is 82.3%. The adiabatic CP has an overall voltage conversion efficiency (VCE) of 92.9% with a total on-chip capacitance of 60 pF. The circuit was designed using 180 nm CMOS technology

Time Stamp – A Novel Time-to-Digital Demodulation Method for Bioimpedance Implant Applications

Bioimpedance analysis is a noninvasive and inexpensive technology used to investigate the electrical properties of biological tissues. The analysis requires demodulation to extract the real and imaginary parts of the impedance. Conventional systems use complex architectures such as I-Q demodulation. In this paper, a very simple alternative time-to-digital demodulation method or ‘time stamp’ is proposed. It employs only three comparators to identify or stamp in the time domain, the crossing points of the excitation signal, and the measured signal. In a CMOS proof of concept design, the accuracy of impedance magnitude and phase is 97.06% and 98.81% respectively over a bandwidth of 10 kHz to 500 kHz. The effect of fractional-N synthesis is analysed for the counter-based zero crossing phase detector obtaining a finer phase resolution (0.51˚ at 500 kHz) using a counter clock frequency ( fclk = 12.5 MHz). Because of its circuit simplicity and ease of transmitting the time stamps, the method is very suited to implantable devices requiring low area and power consumption

Live demonstration: a bioimpedance-based robotic hand control platform using a customised neural network

This work presents a high-accuracy hand gesture recognition platform for robotic hand control. The platform consists of a flexible 8-electrode band, a high-performance electrical impedance tomography (EIT) system, a compact customised neural network deployed on a laptop and a robotic hand. The EIT system captures the bioimpedance features from muscle contraction and bone movement in the upper arm. After training, the customised neural network can predict hand gestures using bioimpedance features. The visitor will experience smooth control of a robotic hand by performing desired gestures using this demo platform

Self-Powered Piezoelectric Biosensing Harvester for Intracardiac Monitoring

This paper presents a novel, biocompatible, in-body energy harvesting piezoelectric biosensing device coupled to sensors for the detection of cardiac allograft vasculopathy. The computational modelling, implementation and measured results of the device are presented. The system includes an ultra-low power readout circuit that operates solely from power harvested from heartbeats. With a natural frequency of 1.52 Hz, the nonlinear piezoelectric harvester generates 56 μW in ex-vivo testing. The device has a 4 × 6 array of fabricated MEMS sensors, which provides over 80% accuracy in detection of heart geometry changes

An integrated bidirectional multi-channel opto-electro arbitrary waveform stimulator for treating motor neurone disease

This paper presents a prototype integrated bidirectional stimulator ASIC capable of mixed opto-electro stimulation and electrophysiological signal recording. The development is part of the research into a fully implantable device for treating motor neurone disease using optogenetics and stem cell technology. The ASIC consists of 4 stimulator units, each featuring 16-channel optical and electrical stimulation using arbitrary current waveforms with an amplitude up to 16 mA and a frequency from 1.5 Hz to 50 kHz, and a recording front-end with a programmable bandwidth of 1 Hz to 4 kHz, and a programmable amplifier gain up to 74 dB. The ASIC was implemented in a 0.18μm CMOS technology. Simulated performance in stimulation and recording is presented

Shaping the Future of Healthcare: The Key Characteristics and Drivers of Smart Hospitals

This paper aims to explore and identify the key characteristics that define smart hospitals, as well as the primary drivers fostering the transformation of conventional hospitals into smart healthcare environments. As the healthcare sector continues to embrace technological innovation, smart hospitals are emerging as a critical model for improving patient care, efficiency, and accessibility. This paper anticipated to offer valuable insights for researchers and stakeholders in healthcare, guiding them in establishing the necessary framework or roadmap for the successful digital transformation of hospitals into smart, technology-driven systems

Emergency medicine in Oman: current status and future challenges

The Sultanate of Oman has a relatively young national health care system that could demonstrate its high performance at an international level. Emergency medicine as a specialty has developed rapidly in the country over the last decade. This has involved the parallel development of local emergency residency training, prehospital emergency care, and emergency nursing programs. This article reviews the progress of emergency care practice in this country from a general primary care system toward becoming an established specialty in hospital, prehospital, and private emergency care settings. It also describes aspects of undergraduate, postgraduate, and continuous emergency medicine education in the country. Further, a glimpse into academic emergency medicine and emergency nursing is provided. Since it describes a developing specialty, the article also attempts to address briefly major future challenges and their importance to the future development of the specialty in Oman