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This work presents a peripheral compensation scheme for AMOLED displays, in which threshold voltage and aging information of driving TFT, and the signal data voltage are analogously added in the pixel circuits without changing the gamma corrections and increasing the bit and voltage range of DAC. Without increasing the resolution and voltage range of DAC, the cost and power consumption are reduced. A driving scheme using current sensing method with adjustable settling time and peripheral compensation system are also proposed. [ABSTRACT FROM AUTHOR]

A TFT integrated gate driver with threshold voltage (Vth) shift compensable low-level holding (LLII) unit is proposed. The gate overdrive voltage (VGOV) of LLII TFTs is kept small and constant due to the compensation effect during the LLII period, leading to much suppressed AVTH and enlarged AVTH tolerance. Simulation results show that the proposed gate driver is able to work properly even the AVTH is up to around (VH-VI). This indicates that the proposed gate driver is of long life. [ABSTRACT FROM AUTHOR]

A current comparison scheme for external compensation circuit of AMOLED displays is proposed. In this scheme, a current comparator is designed to sense the difference between the reference current and the driving current of pixels and to output a corresponding digital signal to the compensation block. For the current comparator, a sense amplifier is used to amplify the current difference, which can effectively increase the accuracy of the current comparator. Simulation results show that the accuracy of the proposed current comparator is 1nA and the sensing error is lower than 0.224 %, when the reference current is 500 nA. [ABSTRACT FROM AUTHOR]

A low-power ESL a-IGZO TFT integrated gate driver, where the gate level of driving-transistor is kept lower than the source/drain level to suppress the serious dock-feed-through effect induced by the large parasitic capacitance of the ESL structured driving TFT Moreover, a new inverter is designed to minimize internal leakage current. Thus, the dependence of power consumption in the gate driver on the overlap-length between gate and source/drain of driving TFT anil the bootstrapping capacitor is much lessened. Simulation results verify the feasibility of the proposed gate driver with 16 stages and manifest that the power consumption is smaller than half of the conventional one whit the same simulation parameters. [ABSTRACT FROM AUTHOR]

The microwave dielectric behavior of sandwich-like Ti3C2 MXene nanosheets with efficient microwave absorption was investigated by a combination of experiments and simulations. The obvious frequency dispersion effect and the double-peaked feature of dielectric spectra in Ti3C2 MXene nanosheets could be observed over the frequency range of 2–18 GHz, giving rise to superior microwave attenuation capability. Furthermore, a revised Drude-Lorentz model was proposed to explain the peaked feature of permittivity, and simulated results were demonstrated to agree well with the experimental measurements. It was concluded that the hopping migration between Ti3C2 MXene nanosheets with longer relaxation time than “micro-dipole” relaxation within nanosheets makes a superior contribution to overall absorbing performance. [ABSTRACT FROM AUTHOR]

This paper presents an IGZO-TFT latch circuit featuring high stability and simple structure with only 5 TFTs per stage. Pass-transistor logic style with gate voltage bootstrapped is used to suppress voltage amplitude loss and achieve a full swing output. Comparison studies are carried out with conventional latch, and results show that the proposed one has compact layout, free DC stress and enhanced immunity to △VTH. [ABSTRACT FROM AUTHOR]

A thorough study on the gate driver integrated with hydrogenated amorphous-silicon thin-film transistors (a-Si:H TFTs) for active-matrix flat-panel display (AM-FPD) is carried out in this work. The single stage circuit of the a-Si:H gate driver consists of input, pull-up, pull-down, and low-level holding units. The operation principle of the driver is described in detail. The subtle static and dynamic characteristics of the a-Si:H TFT based circuit are analyzed systematically for the first time. The long term reliability issue is also addressed. Design equations for determining the device sizes of the circuit are derived. The TFT-LCD panels integrated with the designed gate driver are fabricated to verify the design efficiency. [ABSTRACT FROM PUBLISHER]

An optically transparent metamaterial absorber (MMA) operated in the C-band (4–8 GHz) is optimally designed based on the second-order cross fractal structure. The experimental results show that the reflection loss of the proposed MMA is lower than −10 dB from 3.98 GHz to 8.68 GHz. Two overlapped resonances located at 4.77 GHz and 7.33 GHz, respectively, are caused by the second-order cross fractal structure. Distributions of surface current, electromagnetic field and power loss density are investigated to illustrate the absorptive characteristics and electromagnetic loss mechanisms of the proposed MMA. Moreover, the average optical transmittance of the MMA is close to 75% from 390 nm to 780 nm. The MMA possesses simultaneously strong absorptive capacity in the C-band and high transmittance in the visible light range, showing potential application in special environment. • The designed metamaterial absorber with second-order cross structure shows strong microwave absorption and good optical transmittance. • The reflection loss is lower than -10dB in 3.98~8.68 GHz range. • The average optical transmittance is about 75% in 390~780 nm range. [ABSTRACT FROM AUTHOR]

A precision bandgap reference (BGR) with high power supply ripple rejection (PSRR) and low temperature coefficient (TC) is proposed for the peripheral compensation circuitry of active-matrix organic light-emitting diode (AMOLED) displays. The PSRR is enhanced by a coupling structure of the power supply and a feedback loop of the start-up circuit. Furthermore, a high-order nonlinear compensation method is proposed to reduce the temperature coefficient by utilizing the systematic nonlinear offset voltage within the bandgap circuit. Measurement results of the proposed BGR implemented in an industrial 0.25-μm CMOS process demonstrate a TC of 4.99 ​ppm/°C in a wide temperature range of −40 ​°C–130 ​°C. A PSRR around −80 dB is also achieved by the proposed circuit at low frequency. [ABSTRACT FROM AUTHOR]

With the rapid development of the Internet of Things (IoTs), wearable sensors are playing an increasingly important role in daily monitoring of personal health and wellness. The signal-to-noise-ratio has become the most critical performance factor to consider. To enhance it, on the one hand, good sensing materials/devices have been employed; on the other hand, signal amplification and noise reduction circuits have been used. However, most of these devices and circuits work in an active sampling mode, requiring frequent data acquisition and hence, entailing high-power consumption. In this scenario, a flexible and wearable event-triggered sensor with embedded signal amplification without an external power supply is of great interest. Here, we report a flexible two-terminal piezotronic n-p-n bipolar junction transistor (PBJT) that acts as an autonomous and highly sensitive, current- and/or voltage-mediated pressure sensor. The PBJT is formed by two back-to-back piezotronic diodes which are defined as emitter-base and collector-base diodes. Upon force exertion on the emitter side, as a result of the piezoelectric effect, the emitter-base diode is forward biased while the collector-base diode is reverse biased. Due to the inherent BJT amplification effect, the PBJT achieves record-high sensitivities of 139.7 kPa -1 (current-based) and 88.66 kPa -1 (voltage-based) in sensing mode. The PBJT also has a fast response time of <110 ms under exertion of dynamic stimuli ranging from a flying butterfly to a gentle finger touch. Therefore, the PBJT advances the state of the art not only in terms of sensitivity but also in regard to being self-driven and autonomous, making it promising for pressure sensing and other IoT applications., Competing Interests: Competing interestsThe authors declare no competing interests., (© The Author(s) 2024.)