分析并解决了应用于TDI CMOS图像传感器的模拟累加器的寄生问题.设计中加入了去耦开关,通过引入交流地来消除积分器内的寄生.此外,采用正反馈电容,在积分阶段注入补偿电荷,来补偿无法消除的寄生所带来的影响.在设计中采用0.18μm工艺,供电电压为3.3 V.仿真结果表明,累加器所能提升的信噪比从17.835 d B增加到了21.068 d B,整体线性度达到了99.7%.
A single-transistor CMOS active pixel image sensor(1T CMOS APS)architecture is proposed,By switching the photosensing pinned diode,resetting and selecting can be achieved by diode pull-up and capacitive coupling pull-down of the source follower.Thus,the reset and selected transistors can be removed.In addition,the reset and selected signal lines can be shared to reduce the metal signal line,leading to a very high fill factor.The pixel design and operation principles are discussed in detail.The functionality of the proposed 1 T CMOS APS architecture has been experimentally verified using a fabricated chip in a standard 0.35μm CMOS AMIS technology.
In this paper, a CMOS image sensor(CIS) is proposed, which can accomplish both decorrelation and entropy coding of image compression directly on the focal plane. The design is based on predictive coding for image decorrelation. The predictions are performed in analog domain by 2×2 pixel units. Both the prediction residuals and original pixel values are quantized and encoded in parallel. Since the residuals have a peak distribution around zero,the output codewords can be replaced by the valid part of the residuals' binary mode. The compressed bit stream is accessible directly at the output of CIS without extra disposition. Simulation results show that the proposed approach achieves a compression rate of 2. 2 and PSNR of 51 on different test images.
A switched-current sample-and-hold circuit with low charge injection was proposed. To obtain low noise and charge injection, the zero-voltage switching was used to remove the signal-dependent charge injection, and the signal-independent charge injection was reduced by removing the feed-through voltage from the input port of the memory transistor directly. This current sample-and-hold circuit was implemented using CMOS 180 nm 1.8 V technology. For a 0.8 MHz sinusoidal signal input, the simulated signal-to-noise and distortion ratio and total harmonic distortion were improved from 53.74 dB and -51.24 dB to 56.53 dB and -54.36 dB at the sampling rate of 20 MHz respectively, with accuracy of 9.01 bit and power consumption of 0.44 mW.
We comparatively study two representative ballistic transport models of nanowire metal-oxide-semiconductor field effect transistors,i.e.the Natori model and the Jiménez model.The limitations and applicability of both the models are discussed.Then the Jiménez model is extended to include atomic dispersion relations and is compared with the Natori model from the aspects of ballistic current and quantum capacitance.It is found that the Jiménez model can produce similar results compared with the more complex Natori model even at very small nanowire dimensions.
A 10-bit single-slope analog-to-digital converter (ADC) for time-delay-integration CMOS image sensor was proposed. A programmable ramp generator was applied to accomplish the error calibration and improve the linearity. The ADC was fabricated in a 180 nm 1P4M CMOS process. Experimental results indicate that the differential nonlinearity and integral nonlinearity were 0.51/-0.53 LSB and 0.63/-0.71 LSB, respectively. The sampling rate of the ADC was 32 kHz.
In this paper we report on a study of the CMOS image sensor detection of DNA based on self-assembled nano- metallic particles, which are selectively deposited on the surface of the passive image sensor. The nano-metallic particles effectively block the optical radiation in the visible spectrum of ordinary light source. When such a technical method is applied to DNA detection, the requirement for a special UV light source in the most popular fluorescence is eliminated. The DNA detection methodology is tested on a CMOS sensor chip fabricated using a standard 0.5 gm CMOS process. It is demonstrated that the approach is highly selective to detecting even a signal-base mismatched DNA target with an extremely-low-concentration DNA sample down to 10 pM under an ordinary light source.
