RU1818624C - Analog multiplier of voltage levels - Google Patents

Abstract

The invention relates to the field of analog computing, and can be used in control devices of automation and measurement technology. The purpose of the invention is to increase accuracy and thermal stability. This goal is achieved through the use of a pulse-width modulator in the device, made in the form of a pulse generator 1, a digital generator 2 of triangular functions, a digital-analog converter 3 and a comparator 4, as well as by introducing two pulse train 7 and 8 into the device. 2 silt.

Description

The invention relates to the field of analog computing and can. be used in control devices of automation and measuring equipment.

The purpose of the invention is to increase accuracy and thermal stability.

In FIG. 1 is a functional diagram of an analog voltage multiplier.

1 - pulse generator, 2 - digital generator of triangular functions. 3 - digital-to-analog converter (DAC), 4 - voltage comparator, 5, 6 - elements with single-sided conductivity, 7. 8 - pulse train shapers, 9, 10 - active detecting blocks, 11 summing filtering block.

Figure 2 shows an embodiment of the use of an analog multiplier in a galvanically isolated circuit, where the following notation is introduced:

1 - pulse generator, 2 - digital generator of triangular functions, 3 - digital-to-analog converter (DAC), 4 - comparator. 5 - pulse shaper, 6 - buffer amplifier, 7 - pulse shaper, 8 - active detecting block, 9 - filtering block, 10 - decoupling transformer.

Pulse generator 1 generates three frequency-stable and strictly synchronous pulse sequences. One of these sequences goes to the clock input of the digital generator of triangular functions 2, the purpose of which is the formation of a parallel binary code that describes the time behavior of the triangular function.

From the output bus of the generator of triangular functions 2, the parallel binary code is supplied to the input bus of the DAC 3 operating in bipolar mode, which converts the parallel binary code to

k

00

00

about

ke

the bipolar voltage is triangular in shape.

From the output of the DAC 3, the triangular-shaped bipolar voltage is supplied to the first input of voltage comparator A, and the second input of voltage comparator receives the signal voltage of the first factor X1, which can be either positive or negative.

As soon as the triangular stress reaches a value. signal voltage of factor XI. the comparator changes its state. When the voltage of the triangular signal decreases to a level lower than the signal voltage of the factor X1, the comparator returns to its original state. The process is periodically repeated. As a result of this, a bipolar pulse signal is generated at the output of the comparator, the pulse duration of which is proportional to the voltage of the first factor XI, and the repetition rate is equal to the frequency of repetition of the voltage of a triangular shape. Thus, pulse generator 1, digital generator of triangular functions 2, DAC 3 and voltage comparator 4 together represent a PWM modulator.

The bipolar signal with a rectangular voltage generated by the PWM modulator is divided into two parts by polarity using elements with one-sided conductivity 5, 6, and the element with one-sided conductivity 5 passes the positive part of the pulses, and element 6 - the negative .

Pulses separated in polarity are supplied to two identical pulse former formers 7 and 8, characterized in that the driver 7 serves for receiving pulse packets of positive polarity, and the driver 8 for receiving pulse packets of negative polarity.

Shapers of bursts of pulses work as follows. The PWM signals from the elements with one-sided conductivity arrive at the information inputs of the pulse trainers, and the signal with a positive polarity and the shaper 8 with a negative polarity arrive at the shaper 7.

Clock pulses from the second and third outputs of pulse generator 1 are received at the clock inputs of pulse trainers. These pulses differ only in polarity, with clock pulses of positive polarity coming to shaper 7, and negative to shaper 8.

The pulse train generators form pulse packets of equal polarity, the number of pulses in which is proportional to the voltage of the signal of the first factor XI, the pulse repetition rate is equal to the pulse repetition rate of a triangular shape, and the pulse repetition rate in the packet is two times lower than the clock frequency.

From the output of the pulse train formers, these signals are fed to the control inputs of the active detecting

blocks 9, 10, and pulses of positive polarity go to block 9, and negative pulses to block 10. The information inputs of the active detecting blocks are supplied with the voltage of the signal of the second

factor.

At the same time, the voltage of the signal of the second factor is applied to one of the inputs of the summing part of the filtering unit 11. To the other two inputs of the summing

parts of the filtering unit are fed signals from the outputs of the active detecting units 9, 10. The active detecting units together with the summing part of the filtering unit modulate the signal in amplitude

according to the amplitude of the voltage of the signal of the second factor.

Next, the filtering unit averages the signal, which is a packet of pulses, the number in the packet of which

proportional to the amplitude of the voltage of the first factor, and the amplitude of the pulses in the packet is proportional to the amplitude of the voltage of the signal of the second factor. This is equivalent to a multiplication operation.

in the analogue multiplier variant with galvanic isolation, the operation of the PWM modulator and pulse train former is similar to that described above, except that in this variant the voltage of the factor X1 should only be positive, so DAC 3 operates in unipolar mode, comparator 4 generates pulses of positive polarity, and therefore an element with one-sided conductivity is not required.

A buffer amplifier 6 is needed to match the output impedance of the pulse shaper to the input impedance of the isolation transformer. A pulsed signal consisting of bursts of pulses with a constant repetition rate in a burst is easily transmitted without significant distortion through an isolation transformer.

The pulse shaper 7 serves for the final restoration of the form

signal.

The purpose and operation of the active detecting unit 8 and the filtering unit 9 is also similar to the operation of these units in the main embodiment of the invention.

Claims (1)

SUMMARY OF THE INVENTION An analog voltage multiplier comprising a pulse-width modulator, the input of which is the input of the reference of the first factor, and the output is connected to the inputs of the first and second elements with one-sided conductivity, two active detecting blocks, the outputs of which are connected to the first and second summation inputs filtering unit, the output of which is the output of the multiplier, and the third summing input is connected to the information inputs of the first and second active detecting blocks and input of the second signal of the multiplier multiplier, characterized in that, in order to increase the accuracy and thermal stability, two pulse train shapers are inserted into it, connected between the outputs of the corresponding elements with one-sided conductivity and the control inputs of the active detecting blocks, and the pulse-width converter is made in the form pulse generator, the first output of which is connected to the clock input of a digital generator of triangular functions, connected via a digital-to-analogue converter a target to the first input of the comparator, the second input and output of which are the input and output of the pulse width modulator, the second and third outputs of the pulse generator are connected to the clock inputs of the first and second pulse train drivers, respectively. K-Xt Xg | SHIP - modulator 4G 1 .2 P