Abstract
This paper introduces a new current-controlled current-amplifier suitable for precise measurement applications. This amplifier was developed with strong emphasis on linearity leading to low total harmonic distortion (THD) of the output signal, and on linearity of the gain control. The presented circuit is characterized by low input and high output impedances. Current consumption is significantly smaller than with conventional quadratic current multipliers and is comparable in order to the maximum processed input current, which is ±200 µA. This circuit is supposed to be used in many sensor applications, as well as a precise current multiplier for general analog current signal processing. The presented amplifier (current multiplier) was designed by an uncommon topology based on linear sub-blocks using MOS transistors working in their linear region. The described circuit was designed and fabricated in a C035 I3T25 0.35-µm ON Semiconductor process because of the demand of the intended application for higher supply voltage. Nevertheless, the topology is suitable also for modern smaller CMOS technologies and lower supply voltages. The performance of the circuit was verified by laboratory measurement with parameters comparable to the Cadence simulation results and presented here.
Highlights
The adjustable current amplifiers [1,2] have significant application over many electronic circuits and systems
With respect to the intended application requirements an objective of the work was to develop and design an adjustable accurate current amplifier for current sensor signal processing, and other precise current measurement application, having fulfilled these features simultaneously: (a) low total harmonic distortion of the processed current signal as the most considered parameter wide and linear input range
As obvious, playing brings the other degree of freedom to set gain. As it can come with degradation of linearity for with Vref brings the other degree of freedom to set gain. As it can come with degradation of linearity unadvised large changes and is not necessary, it stays fixed in the presented design
Summary
The adjustable current amplifiers [1,2] have significant application over many electronic circuits and systems. Work [8] presents current amplifier feature allowing gain setting by ratio of resistors (no electronic adjustment is shown) This concept of current gain setting ( of the fixed value) is possible. This type of circuit is especially suitable to realize tunable multi-output current-mode generators as well, where good accuracy and low THD is requested. With respect to the intended application requirements an objective of the work was to develop and design an adjustable accurate current amplifier for current sensor signal processing, and other precise current measurement application, having fulfilled these features simultaneously:. High linearity of the gain control for current gain B < 0.8 acceptable power consumption (comparing to the process signal current) below 5 mW
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