SU1437965A1 - Instrument amplifier - Google Patents

Abstract

This invention relates to a measurement technique. The purpose of the invention is to increase speed. The measuring amplifier contains operational amplifiers (OS) I and 2, differential amplifier 3, resistors 4, 5, 6, 7 and 8 feedback shapers 9 and 10 of the reference voltage and two-sided limiting elements 11 and 12, made on transistors 13 , 14, 15 and 16, current-limiting resistors 17 and 18 and diodes 19, 20, 21 and 22. In the operating mode, the coefficients. The gain is controlled by varying the magnitude of the resistance of the resistor 5. The voltage values at the OU outputs 1 and 2 are limited by the values of the reference voltages specified by the shaper 9 and 10. If the voltage at the OU outputs 1 and 2 is higher than the reference voltages, then the current flowing to the resistors 7 and 8 creates an additional feedback voltage and coefficient. gain is dramatically reduced. This causes a decrease in the output voltage of the op-amp 1 and 2, which eliminates their transition to the saturation mode and ensures a rapid return to the normal gain mode. By adjusting the magnitude of the reference voltages, you can adjust the magnitude of the limiting voltage. The goal is achieved by the introduction of resistors 7 and 8, shapers 9 and 10 and bilateral limiting elements 11 and 12. 1 sludge.

Description

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The invention relates to a measurement technique and can be used in radio engineering installations for various purposes.

The purpose of the invention is to increase speed.

The drawing shows a structural electrical circuit of the measuring amplifier.

The measuring amplifier contains the first and second operational amplifiers (OA) 1 and 2, the differential amplifier 3, the first, second, third resistors 4,5,6 feedback (OS), the first and second additional resistors 7,8 OS, the first and second the formers 9 and 10 of the reference voltage, the first and second bilateral limiting elements 11, 12, made on transistors respectively 13,14 and 15, 16, current limiting resistors 17, 18, diodes 19-22.

The measuring amplifier works as follows

The inputs 1 and 2 (see the drawing) receive the input voltage potentials, the first and second OU.1 and 2 amplify the difference of the input voltages. The amplified differential signal is fed to the inputs of the differential amplifier 3. The gain of the first and second op amps 1 and 2 is determined by the ratios of the first, second, and third resistors 4,5,6 OS. In the working mode, the gain can be adjusted. Change the resistance value of the potentiometric second resistor 5 OS. The voltage at the outputs of the first and second op-amps 1 and 2 is limited. The magnitude of the limit is set by the magnitude of the reference voltage in the first and second drivers 9 and 10 of the reference voltage.

Suppose that inputs 1 and 2 receive voltages such that the outputs of the first and second op amps 1.2 are higher than the reference voltages. If the output of the first op-amp 1 output voltage is greater than the reference voltage at the base of the transistor 13, and the output voltage of the second op-amp 2 is less than the voltage at the base of the transistor 16, then the current from the output of the first op-amp 1 flows through the resistor 17 , 7,5,8, .18, diodes 19,22 and transistors 13,16. From the flowing current on the resistors 7,8, an additional feedback voltage is created, and

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the enhancement effect is drastically reduced. As a result, the output voltage of the first and second op-amps 1 and 2 is reduced. This prevents the first and second opamps 1 and 2 from going into saturation mode and ensures a rapid return to normal gain mode. With a different polarity of the input voltage at the outputs of the first and second op amps 1 and 2, transistors 14 and 15 open, and current flows in a different direction — through a circuit, resistor 18, diode 2, transistor 15, resistors 8,

5.7, transistor 14, diode 20, resistor 17, while creating additional feedback on the resistors

7.8. To the regulator the magnitude of the reference voltages, it is possible to regulate the magnitude of the limiting voltage.

The potentiometric second resistor 5 may have a circuit consisting of resistors and switching elements, allowing to create different terminal resistances.

Claims (1)

I Formula of invention The measuring amplifier contains the first and second operational amplifiers, the non-inverted inputs of which are the corresponding inputs of the measuring amplifier, and the outputs are connected to the inputs of the differential amplifier and connected via series connected first, second, third feedback resistors, as in order to increase speed, the first and second reference voltage drivers, the first and second additional feedback resistors, connected between the inverting input respectively, the first and second operational amplifiers and the points of connection of the first with the second and second with the third feedback resistors, respectively, the first and second bilateral limiting elements, each made on two diodes, are limited by a different resistor and two transistors having a different structure, the collectors of which are combined and are the output of the bilateral limiting element, the input of which is the first output of the current limiting resistor and is connected to the output of the first and second th operational amplifiers, wto31437965 The output terminal through the corresponding diode and second driver formers is connected to the emitters of the transistor-reference voltage connected to the nets, the bases of which are connected to the corresponding inverting inputs of the first and secondary outputs of the drivers of the operational amplifiers of the corresponding reference voltage, with entrances.