In this paper, the second-generation CMOS currentcontrolled- current-conveyor based on differential pair of operational transconductance amplifier has been researched and presented. Since the major improvement of its parasitic resistance at x-port can be linearly controlled by an input bias current, the proposed building block is then called “The Second-Generation Electronically-tunable Current-controlled Current Conveyor” (ECCCI). The applications are demonstrated in form of both 2 quadrant and 4 quadrant current-mode signal multiplier circuits. Characteristics of the proposed ECCCII and its application are simulated by the PSPICE program from which the results are proved to be in agreement with the theory.
A novel current-inversion type negative impedance converter (CNIC) is presented. It is built without the use of any resistors. Furthermore, a second-order low-pass filter based on this CNIC is also analysed. It shows a bandwidth of 50 MHz at 320 µW power consumption and 2 V supply voltage when realized in a 0.35 µm CMOS process.
In the paper, a feedforward linearization method for differential-pair operational transconductance ampliﬁer (OTA) is discussed. The proposed technique is developed using simple differential pair transconductors and linear reference resistor. The concept leads not only to very efficient linearization ofa transfer characteristic oft he OTA but also others the possibility of effﬀective phase compensation. Due to this, the circuit can be used in applications requiring precise phase response (e.g. ﬁlters). SPICE simulations show that for the circuit working with a ±1.25V power supply, total harmonic distortion (THD) at 0.8Vpp is less then 0.1% in comparison to 10.2% without linearization. Moreover, the input voltage range ofline ar operation is increased. Power consumption oft he overall circuit is 0.94mW. The 3rd order elliptic ﬁlter example has been designed and simulated. It turns out that the proposed compensation scheme signiﬁcantly improves the performance of the ﬁlter at higher frequencies.
A new configuration of rectifier suiting CMOS technology is presented. The rectifier consists of only two n-channel MOS transistors, two capacitors and two resistors; for this reason it is very favourable in manufacturing in CMOS technology. With these features the rectifier is easy to design and cheap in production. Despite its simplicity, the rectifier has relatively good characteristics, the voltage and power efficiency, and bandwidth greater than 89%, 87%, and 1 GHz, respectively. The performed simulations and measurements of a prototype circuit fully confirmed its correct operation and advantages.
The article presents measurement results of prototype integrated circuits for acquisition and processing of images in real time. In order to verify a new concept of circuit solutions of analogue image processors, experimental integrated circuits were fabricated. The integrated circuits, designed in a standard 0.35 μm CMOS technology, contain the image sensor and analogue processors that perform low-level convolution-based image processing algorithms. The prototype with a resolution of 32 × 32 pixels allows the acquisition and processing of images at high speed, up to 2000 frames/s. Operation of the prototypes was verified in practice using the developed software and a measurement system based on a FPGA platform.
In this paper a survey of analog application specific integrated circuits (ASICs) for low-level image processing, called vision chips, is presented. Due to the specific requirements, the vision chips are designed using different architectures best suited to their functions. The main types of the vision chip architectures and their properties are presented and characterized on selected examples of prototype integrated circuits (ICs) fabricated in complementary metal oxide semiconductor (CMOS) technologies. While discussing the vision chip realizations the importance of low-cost, low-power solutions is highlighted, which are increasingly being used in intelligent consumer equipment. Thanks to the great development of the automated design environments and fabrication methods, new, so far unknown applications of the vision chips become possible, as for example disposable endoscopy capsules for photographing the human gastrointestinal tract for the purposes of medical diagnosis.
The development of digital microphones and loudspeakers adds new and interesting possibilities of their applications in different fields, extended from industrial, medical to consumer audio markets. One of the rapidly growing field of applications is mobile multimedia, such as mobile phones, digital cameras, laptop and desktop PCs, etc. The advances have also been made in digital audio, particularly in direct digital transduction, so it is now possible to create the all-digital audio recording and reproduction chains potentially having several advantages over existing analog systems.
A simple analog circuit is presented which can play a neuron role in static-model-based neural networks implemented in the form of an integrated circuit. Operating in a transresistance mode it is suited to cooperate with transconductance synapses. As a result, its input signal is a current which is a sum of currents coming from the synapses. Summation of the currents is realized in a node at the neuron input. The circuit has two outputs and provides a step function signal at one output and a linear function one at the other. Activation threshold of the step output can be conveniently controlled by means of a voltage. Having two outputs, the neuron is attractive to be used in networks taking advantage of fuzzy logic. It is built of only five MOS transistors, can operate with very low supply voltages, consumes a very low power when processing the input signals, and no power in the absence of input signals. Simulation as well as experimental results are shown to be in a good agreement with theoretical predictions. The presented results concern a 0.35 1m CMOS process and a prototype fabricated in the framework of Europractice.
An overview of the important techniques for detection of optical radiation from the ultraviolet, through visible to infrared spectral regions is presented. At the beginning single-point devices are considered. Next, di.erent application circuits used in direct detection systems together with elucidation of the design of front-end circuits and discussion of their performance are presented. Third part of the paper is devoted to advanced techniques including coherent detection. Finally, the updated information devoted to readout of signals from detector arrays and focal plane arrays is included. It is shown that detector focal plane technology has revolutionized many kinds of imaging in the past 25 years.