Key Considerations for Power Management in Active Implantable Medical Devices

Within the rapidly advancing field of active implantable medical devices, power management is a major consideration. Devices that provide life critical (or avoiding life threatening) function require a dependable, always-on power source, for example pacemakers. There is then a trade-off with battery lifetime as to whether such devices employ a primary cell or rechargeable battery. With new applications requiring multi-module implants, there is now also a need for transmitting within the body from one device to another. This paper outlines the key considerations and the process to define and optimise the power management strategy. We then apply this to a case study application – developing an implanted, multi-module closed-loop neuromodulation device for the treatment of focal epilepsy

Adaptive Power Regulation and Data Delivery for Multi-Module Implants

Emerging applications for implantable devices are requiring multi-unit systems with intrabody transmission of power and data through wireline interfaces. This paper proposes a novel method for power delivery within such a configuration that makes use of closed loop dynamic regulation. This is implemented for an implantable application requiring a single master and multiple identical slave devices utilising a parallel-connected 4-wire interface. The power regulation is achieved within the master unit through closed loop monitoring of the current consumption to the wired link. Simultaneous power transfer and full-duplex data communication is achieved by superimposing the power carrier and downlink data over two wires and uplink data over a second pair of wires. Measured results using a fully isolated (AC coupled) 4-wire lead, demonstrate this implementation can transmit up to 120 mW of power at 6 V (at the slave device, after eliminating any losses). The master device has a maximum efficiency of 80 % including a dominant dynamic power loss. A 6 V constant supply at the slave device is recovered 1.5 ms after a step of 22 mA

In-body wireline interfacing platform for multi-module implantable microsystems

The recent evolution of implantable medical devicesfrom single-unit stimulators to modern implantable microsys-tems, has driven the need for distributed technologies, in whichboth the implant system and functions are partitioned across mul-tiple active devices. This multi-module approach is made possiblethanks to novel network architectures, allowing for in-body powerand data communications to be performed using implantableleads. This paper discusses the challenges in implementing suchinterfacing system and presents a platform based on one centralimplant (CI) and multiple peripheral implants (PIs) using a cus-tom 4WiCS communication protocol. This is implemented in PCBtechnology and tested to demonstrate intrabody communicationcapabilities and power transfer within the network. Measuredresults show CI-to-PI power delivery achieves 70%efficiency inexpected load condition, while establishing full-duplex data linkwith up to 4 PIs simultaneously

A 4-Wire Interface SoC for Shared Multi- Implant Power Transfer and Full-duplex Communication

This paper describes a novel system for recovering power and providing full-duplex communication over an AC-coupled 4-wire lead between active implantable devices. The target application requires a single Chest Device be connected to a Brain Implant consisting of multiple identical optrodes that record neural activity and provide closed loop optical stimulation. The interface is integrated within each optrode SoC allowing full-duplex and fully-differential communication based on Manchester encoding. The system features a head-to-chest uplink data rate (1.6 Mbps) that is higher than that of the chest-to-head downlink (100kbps) superimposed on a power carrier. On-chip power management provides an unregulated 5 V DC supply with up to 2.5 mA output current for stimulation, and a regulated 3.3 V with 60 dB PSRR for recording and logic circuits. The circuit has been implemented in a 0.35 μm CMOS technology, occupying 1.4 mm 2 silicon area, and requiring a 62.2 μA average current consumption

Four-Wire Interface ASIC for a Multi-Implant Link

This paper describes an on-chip interface for recovering power and providing full-duplex communication over an AC-coupled 4-wire lead between active implantable devices. The target application requires two modules to be implanted in the brain (cortex) and upper chest; connected via a subcutaneous lead. The brain implant consists of multiple identical “optrodes” that facilitate a bidirectional neural interface (electrical recording and optical stimulation), and the chest implant contains the power source (battery) and processor module. The proposed interface is integrated within each optrode ASIC allowing full-duplex and fully-differential communication based on Manchester encoding. The system features a head-to-chest uplink data rate (up to 1.6 Mbps) that is higher than that of the chest-to-head downlink (100 kbps), which is superimposed on a power carrier. On-chip power management provides an unregulated 5-V dc supply with up to 2.5-mA output current for stimulation, and two regulated voltages (3.3 and 3 V) with 60-dB power supply rejection ratio for recording and logic circuits. The 4-wire ASIC has been implemented in a 0.35-μm CMOS technology, occupying a 1.5-mm 2 silicon area, and consumes a quiescent current of 91.2 μA. The system allows power transmission with measured efficiency of up to 66% from the chest to the brain implant. The downlink and uplink communication are successfully tested in a system with two optrodes and through a 4-wire implantable lead

STATUS OF WILD BOAR (Sus scrofa L.) ON THE ISLAND KRK

Divlja svinja u Republici Hrvatskoj autohtona je vrsta. Zakonski spada u krupnu, lovostajem zaštićenu vrstu divljači. Krajem prošlog stoljeća tjerana nagonom za širenjem svoje vrste plivanjem dolazi na otok. Krk je danas veoma kvalitetno stanište za život krupne divljači. Obilje hrane, vode, gusta vegetacija, raznolikost staništa, mir u lovištu, kvalitetno tlo, zapuštanje poljoprivrednih površina koje se pretvaraju u šikaru, rezultira stalnim prirastom postojeće divljači kao i zauzimanje prostora od nove pristigle divljači. Nekada je otok izgledao bitno drugačije nego kako izgleda danas. Obrađivao se svaki komadić zemlje, a danas se većina prepušta sukcesiji. Nova situacija u staništu uvjetuje i pojavu novih životinjskih vrsta. Upravo ovakva situacija pogoduje krupnoj, a ne odgovara sitnoj divljači. Divlje svinje nalaze se i u nelovnim površinama, gdje dolaze zbog hrane i mira, budući se tu zbog zakonskih propisa ne vrši lov. Nelovne površine služe kao rezervat iz kojeg nastanjuju najkvalitetnija staništa. «Crna divljač» na otoku Krku smatra se nepoželjnom vrstom divljači, te se sukladno naredbama ministarstva lovi cijele godine, bez obzira na spol i dob. Zbog odstrjela krmača vodilja, kvalitetnog staništa i velikog odstrjela bucanje i prašenje traje tijekom cijele lovne godine. Divljač pokušava opstati koristeći svoje prirodne mehanizme za očuvanje svoje vrste. U devet lovnih godina s otoka je izlučeno 3.602 grla divljih svinja. Kvalitetu staništa potvrđuje i snaga trofeja odstreljenih veprova, koja zbog nepravilnog odstrjela opada. Želja za potpunim izlučenjem divlje svinje s otoka Krka borba je sa prirodom, a za sada priroda uvijek pobjeđuje. Da li će tako biti i ovoga puta pokazati će budućnostThe wild boar is a native species in the Republic of Croatia. This large game animal is protected by law in closed season. At the end of the last century, driven by instinct to expand its species, it swam from the mainland to the island of Krk. Today Krk provides an excellent habitat for large game animals. Due to an abundance of food, water, dense vegetation, habitat diversity, peaceful hunting ground, fertile ground, abandoned farming areas which have been turning into thick underbrush, the existing game is on a constant increase while new arrivals crowd the existing habitat. The island has changed much and the landscape is not what it was once. Each parcel of land was once cultivated, while today it is left to succession. The new situation in the habitat has caused the emergence of new animal species. It is exactly this type of situation that suits the large and not the small game animals. Wild boars are found in areas not designated for hunting where they come to feed in a peaceful environment since by law hunting is prohibited there. Areas not designated for hunting serve as a game refuge and as such are considered to be habitats of the highest quality. The “black game” on the island of Krk is considered an undesirable type of game animal and pursuant to regulations may be hunted throughout the year, regardless of its sex or age. Due to the eradication of dominant female wild boars, excellent habitat and the large number of killings, mating lasts throughout the entire hunting season. The wild boar tries to survive using its natural mechanisms to preserve its species. In the nine years of hunting 3,602 head of wild boars were eradicated. The quality of the habitat is measured by the number of male boars that were killed as trophies, this being on the decline due to irregular killings. The desire to completely eradicate the wild boar from the island of Krk is a battle against nature and nature is winning, for now. Will this be the case now, only the future will tell

Effects of packaging and ozone treatments on quality preservation in purple figs

The present study was conducted to investigate the effects of different package types and ozone treatments on post-harvest quality of figs. Three different package types (classical-type, modified atmosphere –MAP, consumer-type) and different ozone treatments (0, 5, 10 and 15 minutes) were used in experiments. Purple figs grown in Tekkeköy town of Samsun province were used as the experimental material of the study. Fruits harvested at optimum harvest period were subjected to pre-cooling for a day and then stored in a cold storage at 4°C temperature and 85–90% relative humidity. At the beginning of cold storage and each week of storage, fruits removed from the storage were subjected to weight loss, water soluble dry matter content, titratable acidity, wrinkle, leakage, mold spots, peeling and degustation analyses. Current findings revealed that MAP and 10 or 15-minute ozone treatments had positive impacts on weight loss prevention in figs. While there were not significant differences in other characteristics of treatments, 10 and 15-minute ozone treatments retarded mold spots and leakage in consumer and modified packages

32-channel ultra-low-noise arbitrary signal generation platform for biopotential emulation

This paper presents a multichannel, ultra-low-noise arbitrary signal generation platform for emulating a wide range of different biopotential signals (e.g. ECG, EEG, etc). This is intended for use in the test, measurement and demonstration of bioinstrumentation and medical devices that interface to electrode inputs. The system is organized in 3 key blocks for generating, processing and converting the digital data into a parallel high performance analogue output. These blocks consist of: (1) a Raspberry Pi 3 (RPi3) board; (2) a custom Field Programmable Gate Array (FPGA) board with low-power IGLOO Nano device; and (3) analogue board including the Digital-to-Analogue Converters (DACs) and output circuits. By implementing the system this way, good isolation can be achieved between the different power and signal domains. This mixed-signal architecture takes in a high bitrate SDIO (Secure Digital Input Output) stream, recodes and packetizes this to drive two multichannel DACs, with parallel analogue outputs that are then attenuated and filtered. The system achieves 32-parallel output channels each sampled at 48kS/s, with a 10kHz bandwidth, 110dB dynamic range and uV-level output noise

Design Considerations for Ground Referencing in Multi - Module Neural Implants

Implantable neural interfaces have evolved in the past decades from stimulation-only devices to closed-loop record- ing and stimulation systems, allowing both for more targeted therapeutic techniques and more advanced prosthetic implants. Emerging applications require multi-module active implantable devices with intrabody power and data transmission. This distributed approach poses a new set of challenges related to inter-module connectivity, functional reliability and patient safety. This paper addresses the ground referencing challenge in active multi-implant systems, with a particular focus on neural recording devices. Three different grounding schemes (passive, drive, and sense) are presented and evaluated in terms of both recording reliability and patient safety. Considerations on the practical implementation of body potential referencing circuitry are finally discussed, with a detailed analysis of their impact on the recording performance