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A thin‐film transistors (TFTs) integrated gate driver circuit with bifunctional capacitors for in‐cell touch with horizontal blanking display mode is proposed in this paper. The coupling capacitor, which conventionally enables low‐level‐maintaining parts in display periods, is reused to store transfer charges during touch detection periods. Consequently, only nine TFTs and two capacitors are used for a single stage of the proposed gate driver for in‐cell touch display. Furthermore, the bifunctional capacitor scheme not only avoids the driving TFT from long‐time voltage stress but also suppresses the transfer charges leakage effectively. Therefore, the variation ratios of rising/falling time between adjacent gate driver stages are suppressed within 6%. For a 5.7‐in. display with HD+ resolution, the layout of a single gate driver stage is 623 μm (width) × 171 μm (height). The proposed gate driver circuit has been prepared with the state‐of‐the‐art hydrogenated amorphous silicon (a‐Si:H) TFT manufacturing process. The measured results verified the circuit functions. The gate driver output waveforms are well maintained and being almost independent of touch detection time interval from 100 to 300 μs. [ABSTRACT FROM AUTHOR]

A peak-voltage detection circuit based on a differential comparison structure is proposed to synchronize the control and the input signal. The detection circuit is hence free of reset signals for the sampling capacitors. Furthermore, a two-channel parallel sample and hold structure (i.e., S/H circuit) is used, and a correlated double sampling technique is used, in combination with the ping-pong technique, to sample the signal value and offset voltage within one sample cycle. Consequently, the parallel connected S/H structure can not only extract the offset voltage of the op-amp but also effectively reduce the detection error, which is caused by circuit noise and leakage current. Measurements of the implemented peak detector show that in the case that the detection signal frequency is 20 kHz and the amplitude is 10 mV, the detection error is decreased to 30 µV with the equivalent output noise of 71 n V / H z . [ABSTRACT FROM AUTHOR]

A new pixel circuit is proposed for the realization of high resolution and high uniformity organic light-emitting diode on silicon (OLEDoS) microdisplays in this article. A compensation scheme is adopted to mitigate the influence of threshold voltage variation of the driving transistor on display uniformity. Furthermore, two coupling capacitors are used to reduce the voltage at the gate terminal of the driving transistor in order to extend the data voltage range. The performance of the proposed pixel circuit is verified in an industrial 0.18- $\mu \text{m}$ CMOS process. Simulation results show that the data voltage of the proposed pixel circuit ranges from 0.5 to 3.12 V, which is up to $4.37\times $ wider than the previously published pixel circuits. The emission current error of the proposed pixel circuit varies from −2.1% to 2.08%, under the condition of ±5 mV threshold voltage variation for the driving transistor. The maximum emission current error changes from −10.36% to −2.62% when the OLED turn-on voltage is increased by 5 to 20 mV due to device aging. Furthermore, the proposed pixel circuit only occupies a layout area of $8.1\,\,\mu \text{m}\,\,\times {4}\,\,\mu \text{m}$. [ABSTRACT FROM AUTHOR]

A new source driving circuit to compensate characteristics variations of thin-film transistors for AMOLED displays with high resolution is presented in this brief. The second-generation current conveyor is implemented for rapid current sensing of the feedback line, which is biased with a constant reference-voltage ($V_{{\mathrm{ REF}}}$). Further, the current difference between the current of the driving transistor (${I}_{ {D}}$) and the programming current, i.e., ${I}_{{\mathrm{ DATA}}}$ , is converted into switching voltage through an amplifier with a shorted resistor, to control the input of a ramp voltage (${V}_{{\mathrm{ RAMP}}}$). Thus, the degradations in electrical characteristics of the driving transistor can be compensated in real time, and both the influence of threshold voltage (${V}_{{\mathrm{ TH}}}$) shift and mobility (${ {\mu }}$) variation are effectively suppressed. The current-error rate of the proposed circuit is less than 3% with ${V}_{{\mathrm{ TH}}}$ shift of ±0.5 V or ${ {\mu } }$ variation of ±15%. In addition, the settling time is less than $4~{ {\mu } }{\text s}$ with the panel loading of 1.5 $\text{K}{ {\Omega }}$ and 100 pF at the OLED current (${I}_{{\mathrm{ OLED}}}$) levels ranging from 3 ${ {\mu }}\text{A}$ to 200 nA. [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 integrated five-transistor/one-capacitor approach for realizing a a-Si:H thin-film transistor (TFT) gate driver operating in multiphase-clock mode is proposed and investigated. The driver needs only one large-size TFT and one small-size storage capacitor. The performance and function of the proposed driver are verified experimentally. The dependence of the performance on the device size is studied in detail. Stability of the fabricated drivers is tested using a flexible measurement scheme. Measured results show that the fabricated gate driver can work stably even though the low-level-holding TFTs have a threshold-voltage shift of 19 V. [ABSTRACT FROM AUTHOR]