P.V. Arakcheev – Ph.D.(Eng.), Deputy Head of Department, Bauman Moscow State Technical University
V.L. Bezdelov – Research Scientist, Bauman Moscow State Technical University
E.V. Buryy – Dr.Sc.(Eng.), Professor, Head of Department, Bauman Moscow State Technical University
I.A. Efremov – Student, Department «Technologies of Instrumental Engineering», Bauman Moscow State Technical University
N.E. Orlov – Master, Post-graduate Student, Department «Radio Electronic Systems and Devices»,
Authors of this article performed analysis of circuit design solutions applied for high-precision voltage difference measurement between the nodes of an electrical subcircuit containing elements connected in series attached to a pulsed current source. Such kind of measurements in circuits with pulsed current is difficult to implement because significant speed of measurement means should be provided. Example of circuit that contains diodes connected in series with relative but different current-voltage characteristics is con-sidered.
Possibilities of modern operational amplifiers (OA) with respect to measuring voltage difference between circuit nodes are described and their characteristics are given. Based on the parameters of modern OAs performance characteristics and the main equations determining differential amplifier (DA) operation it was concluded that it was possible to connect several stages of DA with described characteristics to the circuit under study. Each DA stage provides a measurement of the voltage drop across the corresponding semiconductor diode. Equations for resolution and conversion range of DA are given. The necessity of «Rail-to-rail» OA application is discussed.
Methods of synchronization of measurement circuits and pulsed current source, as well as details of analog to digital conversion circuits implementation were considered. Recommendations for selection of circuit design solutions providing galvanic isolation between measurement circuit and output data lines are given. Prospects of CAN bus application in the measurement device were noted on the basis of experience and the sample of such a measurement device implementation is given. CAN bus is being used to provide power and to control the operational modes of the device.
The discussed circuit design solutions made it possible for the first time to record transient processes that occur when pulsed current flows through nine laser diodes modules connected in series used as a radiation sources for optical pumping of a solid-state laser «Implan-10» gain medium and to work out proposals for optimizing cable network used for their connection.
The analysis of theoretical and experimental results indicates that modern OAs providing linear amplification of the input signal with significant dynamic range allow to perform high-precision synchronous direct measurements of voltage drops on sections of a circuit containing elements connected in series. According to analysis of the results, recommendations for CAN bus application to the syn-chronization of signal measurement time intervals, managing the device operational modes and its power supply are given.
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