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Purpose: An x-ray photon interacts with photon counting detectors (PCDs) and generates an electron charge cloud or multiple clouds. The clouds (thus, the photon energy) may be split between two adjacent PCD pixels when the interaction occurs near pixel boundaries, producing a count at both of the pixels. This is called double-counting with charge sharing. (A photoelectric effect with K-shell fluorescence x-ray emission would result in double-counting as well). As a result, PCD data are spatially and energetically correlated, although the output of individual PCD pixels is Poisson distributed. Major problems include the lack of a detector noise model for the spatio-energetic cross talk and lack of a computationally efficient simulation tool for generating correlated Poisson data. A Monte Carlo (MC) simulation can accurately simulate these phenomena and produce noisy data; however, it is not computationally efficient. Methods: In this study, the authors developed a new detector model and implemented it in an efficient software simulator that uses a Poisson random number generator to produce correlated noisy integer counts. The detector model takes the following effects into account: (1) detection efficiency; (2) incomplete charge collection and ballistic effect; (3) interaction with PCDs via photoelectric effect (with or without K-shell fluorescence x-ray emission, which may escape from the PCDs or be reabsorbed); and (4) electronic noise. The correlation was modeled by using these two simplifying assumptions: energy conservation and mutual exclusiveness. The mutual exclusiveness is that no more than two pixels measure energy from one photon. The effect of model parameters has been studied and results were compared withMCsimulations. The agreement, with respect to the spectrum, was evaluated using the reduced χ² statistics or a weighted sum of squared errors, χ² red (≥1), where χ² red = 1 indicates a perfect fit. Results: The model produced spectra with flat field irradiation that qualitatively agree with previous studies. The spectra generated with different model and geometry parameters allowed for understanding the effect of the parameters on the spectrum and the correlation of data. The agreement between the model and MC data was very strong. The mean spectra with 90 keV and 140 kVp agreed exceptionally well: χ² red values were 1.049 with 90 keV data and 1.007 with 140 kVp data. The degrees of cross talk (in terms of the relative increase from single pixel irradiation to flat field irradiation) were 22% with 90 keV and 19% with 140 kVp for MC simulations, while they were 21% and 17%, respectively, for the model. The covariance was in strong agreement qualitatively, although it was overestimated. The noisy data generation was very efficient, taking less than a CPU minute as opposed to CPU hours for MC simulators. Conclusions: The authors have developed a novel, computationally efficient PCD model that takes into account double-counting and resulting spatio-energetic correlation between PCD pixels. The MC simulation validated the accuracy. [ABSTRACT FROM AUTHOR]

A high-speed intra-panel interface with an enhanced reduced voltage differential signaling (eRVDS) scheme is implemented in a 0.18-μm high-voltage CMOS process for the chip-on-glass (COG) TFT-LCD applications. The proposed interface employs the zero-adjustable equalizer to enhance the maximum data rate, the early charge sharing scheme to improve the interface data transfer efficiency, and dynamic biasing technique to reduce a power consumption of the output buffers. Measured result demonstrates the maximum data rate of 1.4 Gbps from a 1.8-V supply voltage with a WQXGA 60-Hz COG TFT-LCD prototype panel. [ABSTRACT FROM AUTHOR]

An average current controller (ACC) that can accurately regulate the light-emitting diode (LED) forward current for lighting applications is proposed. The proposed ACC employs a charge sharing method to achieve a highly accurate average LED forward current by compensating for an error occurred when the LED forward current is sampled. It was fabricated using a 0.35 μm CMOS process technology and occupied a small chip area of 1028 μm × 728 μm. The measurement results showed that the proposed ACC achieved a deviation in the average LED forward current of <0.6% over the entire input voltage range while achieving a maximum power efficiency of 93.6%. Therefore, the proposed ACC is suitable for high-quality LED lighting systems requiring an accurate LED forward current. [ABSTRACT FROM AUTHOR]

A highly reconfigurable charge-domain switched-gm-C complex band-pass filter (CBPF) topology that utilises a semi-passive charge-sharing technique is proposed. It uses only switches, capacitors, digital circuitry for three-phase non-overlapping clock generation and efficient gm-stages. Simulated in a 65 nm CMOS, a first-order CBPF operating at 1 GS/s sampling rate demonstrates flexible tunability of the centre frequency and bandwidth with a highly passive/digital implementation. The presented filter architecture features excellent power efficiency and compatibility with process scaling. [ABSTRACT FROM AUTHOR]

As technology scales down, soft errors, because of single event upsets (SEUs) that affect multiple nodes (through multiple node charge sharing), become a serious concern in nanometre technology integrated circuits. Existing radiation hardening techniques provide partial or no immunity when more than one node are affected. A new latch topology is presented that guarantees soft error tolerance when a single node or any arbitrary combination of node pairs is affected by an SEU. The proposed scheme exploits a positive feedback loop which consists of C-elements. Simulation results validate the efficiency of the new design over existing soft error hardening techniques such as BISER, FERST and TPDICE. [ABSTRACT FROM AUTHOR]