TY - JOUR
T1 - Rail-to-Rail Timing Signals Generation Using InGaZnO TFTs for Flexible X-Ray Detector
AU - Bahubalindruni, Pydi Ganga
AU - Barquinha, Pedro
AU - Tiwari, Bhawna
AU - Pereira, Maria
AU - Santa, Ana
AU - Martins, Jorge
AU - Rovisco, Ana
AU - Tavares, Vitor
AU - Martins, Rodrigo
AU - Fortunato, Elvira
N1 - info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/147333/PT#
info:eu-repo/grantAgreement/FCT/OE/68450/PT#
info:eu-repo/grantAgreement/FCT/OE/62441/PT#
info:eu-repo/grantAgreement/FCT/3599-PPCDT/152013/PT#
info:eu-repo/grantAgreement/EC/H2020/716510/EU#
ECR/2017/000931
POCI-01-0145-FEDER-007688
PY - 2020
Y1 - 2020
N2 - This paper reports on-chip rail-to-rail timing signals generation thin-film circuits for the first time. These circuits, based on a-IGZO thin-film transistors (TFTs) with a simple staggered bottom gate structure, allow row and column selection of a sensor matrix embedded in a flexible radiation sensing system. They include on-chip clock generator (ring oscillator), column selector (shift register) and row-selector (a frequency divider and a shift register). They are realised with rail-to-rail logic gates with level-shifting ability that can perform inversion and NAND logic operations. These logic gates are capable of providing full output swing between supply rails, $V_{DD}$ and $V_{SS}$ , by introducing a single additional switch for each input in bootstrapping logic gates. These circuits were characterised under normal ambient atmosphere and show an improved performance compared to the conventional logic gates with diode connected load and pseudo CMOS counterparts. By using these high-performance logic gates, a complete rail-to-rail frequency divider is presented from measurements using D-Flip Flop. In order to realize a complete compact system, an on-chip ring oscillator (output clock frequency around 1 kHz) and a shift register are also presented from simulations, where these circuits show a power consumption of 1.5 mW and 0.82 mW at a supply voltage of 8 V, respectively. While the circuit concepts described here were designed for an X-ray sensing system, they can be readily expanded to other domains where flexible on-chip timing signal generation is required, such as, smart packaging, biomedical wearable devices and RFIDs.
AB - This paper reports on-chip rail-to-rail timing signals generation thin-film circuits for the first time. These circuits, based on a-IGZO thin-film transistors (TFTs) with a simple staggered bottom gate structure, allow row and column selection of a sensor matrix embedded in a flexible radiation sensing system. They include on-chip clock generator (ring oscillator), column selector (shift register) and row-selector (a frequency divider and a shift register). They are realised with rail-to-rail logic gates with level-shifting ability that can perform inversion and NAND logic operations. These logic gates are capable of providing full output swing between supply rails, $V_{DD}$ and $V_{SS}$ , by introducing a single additional switch for each input in bootstrapping logic gates. These circuits were characterised under normal ambient atmosphere and show an improved performance compared to the conventional logic gates with diode connected load and pseudo CMOS counterparts. By using these high-performance logic gates, a complete rail-to-rail frequency divider is presented from measurements using D-Flip Flop. In order to realize a complete compact system, an on-chip ring oscillator (output clock frequency around 1 kHz) and a shift register are also presented from simulations, where these circuits show a power consumption of 1.5 mW and 0.82 mW at a supply voltage of 8 V, respectively. While the circuit concepts described here were designed for an X-ray sensing system, they can be readily expanded to other domains where flexible on-chip timing signal generation is required, such as, smart packaging, biomedical wearable devices and RFIDs.
KW - flexible radiation sensing system
KW - IGZO TFT
KW - Rail-to-rail logic gates
KW - timing signals
UR - http://www.scopus.com/inward/record.url?scp=85080105943&partnerID=8YFLogxK
U2 - 10.1109/JEDS.2020.2971277
DO - 10.1109/JEDS.2020.2971277
M3 - Article
AN - SCOPUS:85080105943
SN - 2168-6734
VL - 8
SP - 157
EP - 162
JO - IEEE Journal of the Electron Devices Society
JF - IEEE Journal of the Electron Devices Society
M1 - 8981936
ER -