SU1390619A1 - Diode functional converter - Google Patents

Description

(21) 41АЗАОЗ / 24-24

(22) 10/24/86

(46) 04.23.88. Bul Number 15

(71) Moscow Institute of Electronic Engineering

(72) Yu.A.Tarasov, A.A. Maslov, A.A. Agafonov and S.L.Moiseev

(53) 681.3 (088.8)

(56) USSR Author's Certificate No. 926677, cl. G 06 G 7/26, 1982.

Tarasov Yu.A. Design of diode functional converters without voltage reference. - Collection of scientific papers Elements, nodes and mathematical software for control systems. - M., 1985, p. 38-39, fig. 3

(54) DIODE FUNCTIONAL CONVERTER

(57) The invention relates to analog computing. The aim of the invention is to improve the accuracy of the converter by increasing thermal stability, as well as expanding its functionality by reproducing the function with both increasing and decreasing derivatives. The diode function converter contains an operational amplifier 1, a feedback resistor 2, n series-connected reference diodes 34-3, n pairs of scale resistors 4 (-4 ", and 4, -4, ha additional reference diodes and m voltage dividers. Application Voltage dividers 6, along with input large-scale resistors and additional reference diodes 5, provide higher accuracy due to the possible separate adjustment of the UL switch positions, approximation Uj, and the slope of the output characteristic a-, each elementary Thus, the use of additional voltage dividers 6 simplifies the calculation and adjustment of the functional converter, which ultimately increases the accuracy of the proposed technical solution. 2 Il.

I

(L

00

;about

UD

1

This invention relates to analog computing.

The purpose of the invention is to improve the accuracy of conversion by increasing the thermal stability of the device, as well as expanding its functionality by reproducing functions with both increasing and decreasing derivatives,

FIG. 1 is a circuit diagram of a diode function converter, FIG. 2 - graph of the simulated functional dependence.

The diode functional converter (Fig. 1) contains an operational amplifier (OU) 1, a feedback resistor 2, n series-connected diodes, n pairs of scale resistors n ,,, F additional reference diodes Sj-Sr, and n -1 dividers 6,; - 6f, voltages containing scale resistors 7, -7 "., And 8, -8".,,

The diode functional converter (Fig. 1) operates as follows.

The first non-linear diode cell (dn), made on the scale resistors 4, 4 (and the reference diode 3, turns on at the input voltage and, 0. The slope of its linear characteristic at the output of the op-amp 1 is

Each subsequent i- (, 3 ,, .., п) DAY is turned on at node U, and turned off at node Uxdti).

With resistances Rig and R; Shoulder divider 6 significantly lower resistances of large-scale resistors 4.

and h

voltage

(i-i) u iki ± JRiii. )

R;

f-i

Where

R;

6g.

- coefficient

Ri + R;

 2 transfer of the i-th divider 6 | tension

Accordingly, the turn-off voltage and) ((DAY, determined by i series-connected reference diodes 3, -3 J, j-th reference diodes 5; and the ratio of resistances R

bad

and R; is determined from the equation + UxiUoJi- (i-1) ujR; .

+ R;

 iU

D;

n 2 (5)

and

x (

 (i-1) U + - Oi

UK Rj, + Rja

R

. (6)

Ja

And, finally, the steepness of the linear characteristic of the inclusions of the i-th DAY in the interval of variation of the argument | 1. $ VENT V .; Uy ё U (; ,, i

K, tgoi,

RO

R ,, + R ,,

(1) 35 K; tgc .; - | ..lL.

where r

- resistance of resistor

2 feedback; R ,, R, are the resistances of resistors respectively 4 (

and 4 ,,.

when the voltage at the junction of resistors 4 and 4 is reached is the voltage of the unlocking of diode 3, with its negligible resistance in the conducting direction, the component of the voltage at the output of the op-amp 1, caused by the first DAY, is equal to

itz and

0

R ..

The voltage U, at which diode 3 is unlocked and correspondingly: the first DAY is automatically turned off, is determined; Thermal stability is improved, for example, when 50 diodes are opened, and a practically equal change in the voltage decreases on these diodes. Stabilization current through large-scale resistors 4 ;, -4; For example, increment

the resistance ratio of the current resistors 55 through the scale resistor 4,

and 4

g

and 1

 in R

+ R

(3)

g

(7)

Thus, having determined from relation (4), the sum of the resistances R; + R; from formula (7) and then the ratio between the resistances of R- and R; from expression (6) with respect to U, j, U, K; and U) ((, +,) can provide a piecewise linear approximation of functions as with decreasing.

and with a derivative within the predetermined range of the argument U variation (Fig. 2).

Increased thermal stability is guaranteed, for example, with open diodes, and with a practically identical change in the voltage uUjj of these diodes by stabilizing the currents through the scale resistors 4 ;, -4; For example, increment

current through the scale resistor 4, will be

Ayb

 H-l up - (i-1) uUa uUjj

Rl

R;, - (")

those. it depends on the change in the characteristics of not all, but only one diode.

Before the inclusion of the i-th day at U

temperature error is missing altogether.

Claims (1)

DETAILED DESCRIPTION OF THE INVENTION Diode function converter comprising an operational amplifier, feedback resistor, n in series according to the included reference diodes and n pairs of series-connected large-scale resistors, the total output of the table resistors of each i-th (where, 2, ..., n) pair to the anode of the corresponding reference diode, the free output of the first scale resistor of the first pair is the input of the converter; the free output of the second scale resistor of the first pair is connected to the inverting input of eratsionnogo amplifier and a first terminal of a resist ra feedback connected to the output terminal of the second operational amplifier, which is the output of the converter, the cathode of the first diode and the reference non-inverting input of the operational amplifier is connected to and.  P -Wh ten j, -25 20 by the bus of zero potential, that is, in order to increase accuracy by increasing thermal stability, as well as expanding functional capabilities due to the recovery of functions with both increasing and decreasing derivatives, it is inserted (p-1) in series according to the included additional reference diodes, (p-1) voltage dividers, each made on two series-connected large-scale resistors, the common output of which is the output of the voltage divider, and the free outputs of the first and second of the base resistors are connected respectively to the information input of the converter and the zero potential bus, the output of each j-ro (where, 2,3, ..., p-1) voltage divider is connected to the free output of the first scale resistor, respectively (1 + 1) - the first pair, the cathode of each j-ro of the additional diode is connected to the free output of the second large-scale resistor of the corresponding i-th pair, the free output of the second large-scale resistor of the nth pair is connected to the anode of the (n-1) -th additional reference diode.