SU1354121A1 - Voltage comparison device - Google Patents

Abstract

The invention relates to a measurement technique and can be used in measurement systems and the control of electrical quantities. The purpose of the invention is to improve the accuracy of voltage comparison as a result of the introduction of two resistors and an operational amplifier into the device. The device contains resistors 1-4, an operational amplifier 5, a comparator 6 and a voltage divider 7, made on resistors 8 and 9. The error compensation due to the presence of a hysteresis of the transfer characteristic of the comparator 6 is achieved by the fact that at any moment-time inversion input The comparator 6 is supplied with the appropriate voltage from the output of the operational amplifier, which provides an increase in the accuracy of the measurements to be made. The device can operate with both positive and negative input voltages. 1 il. i CL L / L 00 SP & ND

Description

The invention relates to a voltage comparison measurement technique and can be used in a system for measuring and controlling electrical quantities.

The aim of the invention is to increase accuracy.

The drawing shows a diagram of the device.

The device contains resistors 1-A, operational amplifier 5, comparator 6, voltage divider 7, made on resistors 8 and 9,

The output of the operational amplifier 5 is connected to the inverting input of the comparator 6. The voltage divider 7 on the resistors 8 and 9 is connected to the output of the comparator 6 by the first output of the comparator 6, the output of the resistor 8 is connected to the common bus of the device, and the middle connection point of the resistor 8 and 9 is connected to The input to the comparator 6. The resistor 1 is connected to the non-inverting inputs of the operational amplifier 5 and the comparator 6 by its terminals. The sources of the compared voltages 10 (114) and 11 (Uj) are connected via resistors 3 and 2 to the inverting and non-inverting th input of the operational amplifier 5, respectively. A resistor A is connected between the inverting input of the operational amplifier 5 and its output. The output of the comparator 6 is the output of the device. Operational amplifier 5 and resistors 1-A form an adder.

The device works as follows.

With the help of resistors 8 and 9, the hysteresis of the transfer characteristic of the comparator 6 is introduced, which ensures a clear switching of its voltage at any rate of change of the input signal.

Compensation of the error due to the hysteresis of the transfer characteristic of the comparator 6 is achieved by the fact that at any time the voltage U is applied to the inverting input of the comparator 6. From the output of the operational amplifier 5:

and - K (UI - and,) + and

n

(one)

where k

- transfer coefficient sum of the torus of input signals

and, And Uj, and and - the voltage of the switching threshold from the divider 7 voltage. . In order for the signal at the output of operational amplifier 5 to comply with equation (1), the non-inverting inputs of comparator 6. and operational amplifier 5 are connected via resistor 1, and the following relationship between the resistances of the resistors is ensured:

0

five

five

0

five

0

R,

Rl

where R ,, R,

0

five

R4

R,

R

 TO,

(2)

i 3 4 are the resistance values of the resistors 1-4, respectively.

A change in the output voltage level, causing a hysteresis voltage bias, does not lead to a deterioration in accuracy, since it is automatically taken into account by the adder based on the operational amplifier 5 and resistors. 1 -A.

Claims (1)

The device is operational with both positive and negative input voltages. Invention Formula A voltage comparison device containing a comparator, a voltage divider consisting of two resistors, a first terminal of the first resistor connected to the output of the comparator, a terminal of the second resistor connected to the common bus of the device, and their middle point is connected to a non-inverted output of the comparator and the first terminal of the third resistor, characterized in that, in order to improve the accuracy of the comparison, the fourth, fifth and sixth resistors, as well as an operational amplifier, are additionally introduced into it, the first terminal of the fourth resistor and is connected to the non-inverting input of the operational amplifier and the second terminal of the third resistor, and its second output is the first input of the device, the first terminal of the fifth resistor is the second input of the device, its other terminal is connected to the inverter input of the operational amplifier and through the sixth resistor to the output an operational amplifier and an inverting comparator input, the output of which is the output of the device.