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http://dx.doi.org/10.5207/JIEIE.2005.19.8.116

Accuracy Enhancement Technique in the Current-Attenuator Circuit  

Kim, Seong-Kweon (국립목포해양대학교 해양정보통신공학과)
Publication Information
Journal of the Korean Institute of Illuminating and Electrical Installation Engineers / v.19, no.8, 2005 , pp. 116-121 More about this Journal
Abstract
To realize the tap coefficient of a finite impulse response(FIR) filter or the twiddle factor of a fast Fourier transform(FFT) using a current-mode analog circuit, a high accurate current-attenuator circuit is needed This paper introduces an accuracy enhancement technique in the current-mode signal processing. First of all, the DC of set-current error in a conventional current-attenuator using a gate-ratioed orient mirror circuit is analyzed and then, the current-attenuator circuit with a negligibly small DC offset-current error is introduced. The circuit consists of N-output current mirrors connected in parallel with me another. The output current of the circuit is attenuated to 1/N of the input current. On the basis of the Kirchhoff current law, the current scale ratio is determined simply by the number of the current mirrors in the N-current mirrors connected in parallel. In the proposed current-attenuator circuit the scale accuracy is limited by the ac gain error of the current mirror. Considering that a current mirror has a negligibly small ac gain error, the attainable maximum scale accuracy is theoretically -80[dB] to the input current.
Keywords
Current mode Circuit; current-attenuator; DC of set-current;
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