Low-Power Bootstrapped Rail-to-Rail Logic Gates for Thin-Film Applications

Papadopoulos, Nikos; Lee, Czang-Ho; Tari, Alireza; Wong, William S.; Sachdev, Manoj

doi:10.1109/jdt.2016.2561841

Cited by 12 publications

(5 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such logic gates may employ additional transistors with a feedback function that reduces transistor leakage after the switching action has occurred 38 . Feedback circuits at the system level for disabling large idle blocks are also unexplored in TFT circuits.…”

Section: Digital Logic Gatesmentioning

confidence: 99%

The development of flexible integrated circuits based on thin-film transistors

2018

View full text Add to dashboard Cite

T hin-film transistors (TFTs) are currently the dominant technology for in-pixel switches and drivers in flat-panel displays. Trends in consumer electronics demand ever-higher display resolution and brightness, lower power consumption, and new features and form factors (such as curved and foldable displays). This drives TFT devices to deliver more complex functions than simply switching. For example, recent bezel-less displays delegate the task of row selection to TFT circuits integrated next to the pixel array. Such driver circuits comprise thousands of switches operating together -previously a job for silicon chips mounted around the display.Beyond displays, how far can thin-film circuits go in terms of replacing silicon complementary metal-oxide-semiconductor (CMOS) chips? Fig. 1 illustrates the key advantages of thin-film circuits on flexible substrates. The circuits can be fabricated on large substrates, thereby creating very thin, lightweight and ultra-flexible electronics 1,2 . Folding, rolling or crumpling such flexible circuits is possible without destroying the electronic functionality. Because of these properties, a flexible TFT-based microprocessor 3 (Fig. 1d) or thin-film near-field communication (NFC) tag (Fig. 1e) can, for example, be integrated imperceptibly into any object. TFT technologies also have considerable potential for fabrication on ultrathin stretchable substrates 4 that can be made porous to create breathable devices for contact with skin. With these features, thin-film integrated circuits (ICs) could be a game-changer for wearable electronics. Ultrathin, conformable ICs in the form of a tattoo could be used to monitor vital body parameters, communicating these parameters directly to a patient's smartphone or a medical database.In this Perspective, I discuss the potential of thin-film circuits on plastic substrates for the development of Internet of Things (IoT) and wearable applications. First I look at the different TFT technologies that can be realized on flexible substrates, and then discuss the impact TFT technology will have on circuit design at the level of digital logic gates and very-large-scale integration (VLSI) digital circuits. For the latter, I consider the use of thin-film ICs in the creation of low-cost radiofrequency identification (RFID) tags for everyday items. Flexible chips may initially be used to simply identify each item. Then, when the RFID chip is potentially replaced with a thinfilm NFC chip, standard smartphones and tablets equipped with NFC readers could identify objects and connect them to the cloud. Another advantage of thin-film IC technology is its potential to be combined with sensor or signage technology, thereby integrating more functionality into the objects, which is discussed in a section on analogue circuits. Finally, I will briefly examine the potential of silicon CMOS chip technology to be interfaced directly with TFT circuitry. TFT technologyThe development and optimization of transistor technologies are driven by four important figures of me...

show abstract

Section: Digital Logic Gatesmentioning

confidence: 99%

The development of flexible integrated circuits based on thin-film transistors

2018

View full text Add to dashboard Cite

show abstract

“…For a 19-stage ring oscillator, a power reduction of up to one order of magnitude is measured with 50% increase in stage delay for the same supply voltages by optimized TFT sizing of the logic gates. Furthermore, power and area reduction can be achieved with the use of DG logic [4] already available in the technology and feedback reduces power up to 90% [25]. Finally, the use of more logic gates and improvement of the digital flow can decrease the number of used TFTs in the block.…”

Section: B Digital Control Blockmentioning

confidence: 99%

Toward Temperature Tracking With Unipolar Metal-Oxide Thin-Film SAR C-2C ADC on Plastic

Papadopoulos

Roose

Steen

et al. 2018

IEEE J. Solid-State Circuits

Self Cite

View full text Add to dashboard Cite

The maturity of metal-oxide thin-film transistors (TFT) highlights opportunities to develop robust and low-cost electronics on flexible and stretchable substrates over large area in an industry-compatible technology. Internet-of-Everything applications with sensor nodes are driving the development of analog-to-digital converters (ADCs). In this paper, a self-biased and self-digital-controlled successive approximation ADC with integrated references and sensor read-in circuitry together with a printed negative temperature coefficient (NTC) sensor using unipolar dual-gate metal-oxide (InGaZnO) TFTs is demonstrated. The system is operated at a clock of up to 400 Hz and a total power dissipation of 245 mW (73 µW from analog) at a maximum power supply of 30 V is measured. The radio-frequency identification-ready ADC comprises of a total of 1394 indium-gallium-zinc oxide TFTs and 31 metal-insulatormetal capacitors. A figure of merit of 26 nJ/c.s. is achieved from the ADC driven from external microcontroller. The robustness of the various blocks of the chip is characterized and the yield is discussed.

show abstract

“…In addition, it requires two explicit signals for controlling the operation in pre-charge and evaluation phase. On the other hand, the gates reported in [20] employ a large number of transistors for implementation of simple gates. For a single inverter, 7 TFTs were used to obtain the desired performance.…”

Section: Introductionmentioning

confidence: 99%

Rail-to-Rail Timing Signals Generation Using InGaZnO TFTs For Flexible X-Ray Detector

Bahubalindruni

Tiwari

Pereira

et al. 2020

IEEE J. Electron Devices Soc.

View full text Add to dashboard Cite

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. INDEX TERMS Rail-to-rail logic gates, IGZO TFT, timing signals, flexible radiation sensing system.

show abstract

Low-Power Bootstrapped Rail-to-Rail Logic Gates for Thin-Film Applications

Cited by 12 publications

References 18 publications

The development of flexible integrated circuits based on thin-film transistors

The development of flexible integrated circuits based on thin-film transistors

Toward Temperature Tracking With Unipolar Metal-Oxide Thin-Film SAR C-2C ADC on Plastic

Rail-to-Rail Timing Signals Generation Using InGaZnO TFTs For Flexible X-Ray Detector

Contact Info

Product

Resources

About