Multichannel analog-to-digital converters based on current mirrors for the optical systems

Abstract

The paper considers results of designing and modeling analogue-digital converters (ADC) based on current mirrors for the optical systems and neural networks with parallel inputs-outputs. Such ADC, named us multichannel analog-to-digital converters based on current mirrors (M ADC CM). Compared with usual converters, for example, reading, a bit-by-bit equilibration, and so forth, have a number of advantages: high speed and reliability, simplicity, small power consumption, the big degree of integration in linear and matrix structures. The considered aspects of designing of M_ADC CM in binary codes. Base digit cells (ABC) of such M_ADC CM, series-pipelined are connected in structures, consist from 20–30 CMOS the transistors, one photodiode, have low (1,5–3,5) supply voltage, work in current modes with the maximum values of currents (10–40)µA. Therefore such new principles of realization high-speed low-discharge M_ADC CM have allowed, as have shown modeling experiments, to reach time of transformation less than 20–30 nS at 5–6 bits of a binary code and the general power 1–5 mW. The quantity easily cascadable ABC depends on wordlength ADC, and makes n, and provides quantity of levels of quantization equal N=2n. Such simple enough on structure M ADC CM, having low power consumption ≤ 3 + 5mW, supply voltage (3–7)V, is provided at the same time with good dynamic characteristics (frequency of digitization even for 1,5µm or 0,35 µm- CMOS-technologies has made 40 MHz, and can be increased 10 times) and accuracy (Δ quantization = 156,25nA for I max = 10µA) characteristics is show. The range can be transformed optical signals, taking into account sensitivity of modern photodetectors makes 20–200 µ in such ADC. M_ADC CM open new prospects for realization linear and matrix (with picture operands) micro photoelectronic structures which are necessary for neural networks, digital optoelectronic processors, neurofuzzy controllers, and so forth.