SU1619315A1 - Code-controlled inductance module - Google Patents

Abstract

The invention relates to automation, radio engineering and analog-to-digital computing. The purpose of the invention is to expand the field of application by providing a linear dependence of the equivalent inductance of the block on the control code. The coding control inductance block contains two operational amplifiers 3 and 4, multiplying a digital-to-analog converter (made on the operational amplifier 5 and a resistive matrix 6 of a ladder type with code-controlling switches), four scaling resistors 7-10 and an integrating capacitor 11. The principle of operation is based on the control of the transmission coefficient of the integrator feedback circuit, performed on amplifier 3, using multiplying digits of the converter transducer. The presence of the linear dependence of the equivalent inductance of the block on the values of the control code makes it possible to extend the range of the block application in active power, digital measuring bridges, code-controlled inductance measures, etc. 1 il. and

Description

The invention relates to automation, radio engineering and analog-to-digital computing and can be used, in particular, in active filters, digital measuring bridges of alternating current, code-controlled measures of inductance, devices for modeling parameters of electrical circuits. YU

The aim of the invention is to expand the scope by providing a linear dependence of the equivalent inductance of the block on the control code. fifteen

The drawing shows a structural diagram of a block code-controlled inductance.

The block contains the first 1 and second 2 analog outputs, the first 3 and second 20 second 4 operational amplifiers, multiplying the digital-to-analog conversion. a body (U11AP), made on the third operational amplifier 5 and a ladder-type resistor matrix 6 with co-controlled 25 switches. In addition, the block contains from first to fourth scaling resistors 7-10 and an integrating capacitor 11.

As part of the resistive matrix 6 ZO there are communication resistors 12, discharge resistors 13, a matching resistor 14 and a feedback resistor 15, coordinated in terms of resistance and temperature coefficient with other resistors of the matrix 6.

In the general case, any code-controlled resistive matrix can be used, the mutual conductivity of which between the input and the current output is a deterministic function of the input control code. To ensure high accuracy of the block, it is necessary to coordinate the mutual conductivity of the matrix, feedback resistor 15, which is achieved by the implementation of resistors 12-15 in a single technological cycle. Moreover, the scatter of the absolute values of the resistances of the indicated resistors does not affect the accuracy of the inductance specification (provided that the accuracy and stability of the ratios of the indicated resistances are maintained).

To obtain a small discreteness of $ 5 or, conversely, a wide range of inductance, matrices 6 with a non-binary ratio of the resistances of the resistors 12 and 13, 14 can be used.

The block works as follows.

In the initial state, the control code p applies to the digital inputs. For matrix 6 of type R-2R, the voltage transfer coefficient from the input of matrix 6 to the output of amplifier 5 is

K = -η · 2 “ ^Ν , (1) where N is the width of the matrix 6.

When the input voltage U _{& x is} applied between the terminals 1 and 2, a current I _{6χ arises} . The direction of the partial currents 1 ₇ and Ig flowing through the resistors 7 and 8 is chosen so that the resulting conductivity G is positive.

The obvious equations are written down:

G - * ^Rin - Λ ϊ & λ 'and _{Rin vx} n ⁼ 7 * 7 "(2) (3) ^t = 8 ^<u h- ^and 4) / ^r S, (4).

where u

- voltage at the output of the amplifier 4.

To find the voltage, we note that the voltage U ₅ at the output of the “amplifier 3 is connected with the input voltage by the ratio:

U ₃ = U _8x / (jcOR ₇ · C _<4 -K), (5).

where R and C are the resistance and capacitance of the register 7 and the capacitor 11.

Voltage considering (2):

and, - ₍₆₎ ['* ⁽ ''iU'R _T c „.K' sf] 'where R ^ and R _<0 are the resistances of resistors 9 and 10.

Taking into account expressions (2), (3), (4), (6), we can write _G _ 1 _ R <o ₊ _____________ R <o

P B 7 Eg 'jCO'R-f Βθ' Β ^ · K (7)

Analysis of expression (7) allows us to conclude that the block allows you to simulate inductance = K'R ₇ · Rg · R _? · C ₍₍ / R _<0 with active conductivity connected in parallel:

e ~ 1 / ^ 7 ~ K o7 (R £ 'Rd)

The value of the equivalent conductivity is independent of the code and can be chosen both positive and negative.

Under the condition R-j'R < ₀ = Rg-R? block pos; allows you to simulate a lossless inductance whose value is directly proportional to the input code:

L ₃ = η · 2 * · ^Κ · R *. With _and . (8) _f

To compensate for the influence of the input current of amplifier 3, it is sufficient to connect its inverting input to a common bus through a resistor equal in resistance to resistor 7. j

The presence of a linear dependence of the equivalent inductance of the considered block on the values of the control code allows us to expand the scope of its application. 7

Claims (1)

Claim A code-controlled · inductance unit containing a first operational amplifier connected by an output to the analog input of a multiplying digital-to-analog converter, a digital input to 15 ^{6 of} which is the control input of the back end, an integrating capacitor, the first lining of which is connected to the first output of the first scaling resistor connected to the first analog output of the block, the first output of the second scaling resistor and the non-inverting input of the second operational amplifier connected by the inverting input to the first conclusions of the third and the fourth scaling resistors, and the output with the second terminals of the second and fourth scaling resistors, the second analogs the block output terminal is connected to the zero potential bus of the block, characterized in that, in order to expand the scope by providing a linear dependence of the equivalent inductance of the block on the control code, the second lining of the integrating capacitor is connected to the output of the multiplying digital-to-analog converter, and the first operational amplifier is connected to the inverting input to the bus of the zero potential of the block, the non-inverting input to the second terminal of the first scaling resistor, and the output to the second terminal of the third scaling resistor.