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Dlje časa trajajoča povišana raven krvnega sladkorja oziroma raven glukoze v krvi je tesno povezana s pojavom diabetesa ali sladkorne bolezni tipa 2 in posledično resnih zdravstvenih težav kot so nevropatija, srčno-žilne bolezni, nagnjenost k okužbam itd. Dandanes edini učinkovit in zanesljiv način merjenja krvnega sladkorja je neposredna analiza krvi (kapilarne ali venozne), intersticijske in drugih telesnih tekočin. Najpogostejša je prva omenjena metoda. Njena glavna slabost je prebadanje pacientove kože (npr. blazinic na prstih), ki pogosto povzroča bolečino in predstavlja tveganje, saj lahko virusi in bakterije prodrejo v telo. Razvoj učinkovite in natančne neinvazivne metode za merjenje ravni krvnega sladkorja je bil prepoznan kot ključni korak za bodoče študije krvnega sladkorja in implementacije takih metod v prenosne naprave. V tej disertaciji je predstavljeno merjenje ravni krvnega sladkorja na osnovi merjenja impedance kože. Merilni sistem z integriram vezjem (ASIC) je predstavljen in analiziran. Izdelano integrirano vezje v 350 nm CMOS tehnologiji z dimenzijami 1223 µm x 1388 µm tipično troši 450 µA pri napajalni napetosti 3,3 V in deluje v frekvenčnem razponu 5 kHz do 16 MHz. Sistem izkazuje dober linearni odziv za bremena do nekaj kW, kar je primerno za meritve impedance kože. Blood glycemic level, also known as blood sugar level or blood glucose level, especially that reaching high values (hyperglycemia) and persisting in time, is strongly linked to the development of type 2 diabetes and consequently serious medical conditions such as neuropathy, cardiovascular diseases, sensitivity to infections etc. Nowadays the only effective and reliable way of monitoring blood sugar level is to directly analyze the blood (capillary or venous), interstitial or other body fluids. The former method is the most used. Its main disadvantage is puncturing of patient skin (finger pricking for example) which frequently causes pain and the risk of viruses and bacteria entering the body. The development of an effective and accurate noninvasive method for blood glucose monitoring has been recognized as a crucial goal for future studies of blood sugar and implementations of such methods into wearable devices. In this thesis we propose monitoring of blood glucose level employing skin impedance measurement. A measurement system featuring an Application-Specific Integrated Circuit (ASIC) is presented and analyzed. The fabricated ASIC in 350 nm CMOS technology with dimensions 1223 µm x 1388 µm, typically consumes 450 µA at 3.3 V supply voltage and operates in frequency region from 5 kHz to 16 MHz. The system exhibits a good linear response for loads up to a few kW, making it suitable for skin impedance measurements. |
