SU1233180A1 - Element with controlled resistance - Google Patents

Abstract

The invention relates to computing and can be applied in automatic control and control devices. The purpose of the invention is to increase the accuracy in controlling the average value of the resistance according to a quadratic law. An element with controlled resistance contains 1kit five scaling resistors, two smoothing capacitors, two switches, an operational amplifier and an inverter. This invention is used to form the dependence of the type g Kb, where I is the resistance of the element from the relative duration 0 of the control width S / T, which represents a sequence of rectangular pulses of duration T and repetition period T, K is the proportionality coefficient. 1 il. with e to co oo

Description

The invention relates to computing and can be applied in automatic control and control devices, where it is necessary to form the dependence g K 9 of the resistance g - the element of relative length & the controlling width-modulated signal B, which is a sequence of rectangular pulses of duration t and repetition period T, K is a proportionality coefficient,

The purpose of the invention is to increase the accuracy in controlling the average resistance value according to kva.cratis law.

The drawing shows the functional diagram of the element with controlled resistance

The control element 15M impedance contains five scale resistors 1-5, first 6 and second 7 smoothing capacitors, the first 8 and second 9 keys, the operational amplifier 10, the inverter 11, the first 12 and second 13 signal terminals of the element, control input 14 of the element .

The element with controlled resistance works as follows.

The control input 14 receives a stream of rectangular impulses modulated in duration. At the output of the inverter 11, a width-modulated signal is generated, which controls khpochey 8. A key 9 controls the outgoing width-modulated signal with a relative duration of B. Smoothing capacitors 6 and 7 provide the suppression of the high voltage harmonics 5 arising from the switching of keys 8 and 9. Due to this, the quarter-scale resistor 4 turns out to be alternating with alternating current from the impulses of the controllable depot: and from the third and fifth 3 and 5 large-scale resistor keys 8 and 9 and capacitor 7

The average value of the variable for example of the op amp) 0 equals;

 vu, n ,, (1)

where Up is the mean value eg 5v: EnLa

on the capacitor 7; I. - The current flowing through the quadruple scale resistor 4 O

233180 2

C is the conductivity of the third scale resistor 3. In terms of the grounding of the second signal bus 13 and the ideality of the operational amplifier 10 ,, the current through the resistor 4 is equal to

1f and, G ,. ,, (2) where and, - the potential of the non-inverting input of the operational force - 10 bodies 10;

G is the conductivity of the resistor 4. The average value of the voltage on the capacitor 7 is found from the condition of dynamic equilibrium

15 O. Spd Qfc ,, p-j- (3) where Q, Q- charge, acquired by a capacitor at the stage of charge; charge, loss of capacitor at discharge stage. About 20 In the closed state of the key 9 for the time period we have;

Cf (Uc - and,) 2Gt, (4) where G is the large-scale conductivity: resistors 3 and 5,

With the open state of the key 9 and the closed state of the key 8 during the time T- (we have:

25

, p (Ue - and,) G (T-t) (5) 5) and (6)

thirty

 - e

Considering expressions, we get:

 Q: .. cf

by

lap

+ Q

U)

(LV-UjG (T (6)

T-f

The charge is termed 1 by capacitor 7 at the stage; the bit during the period — 35 ka of time — T- t, is equal to:

Oragh iUy - lUG (Tlt), (7)

G - large scale output

40

r,; j; e

resistor about.

Cs of equation (4) - taking into account overlapping;, 7 / and (8) we obtain: r, ... Ui () i.L1-, 0)

2

(8) including (2)

Then from the expression we get;

GT - 11 -OV

and I L f- e

Under the influence of this voltage through the second massable resistor 2 and: current flows

one

(ten)

Chapter 1, e C, is the conductivity of resistor 2, and § is the relative duration of the signal at control input 14.

Then the resistance of the element as a whole obeys the dependence I, 2, 2G

Mr. R,

, p (Ue - and,) G (T-t) (5) 5) and (6)

 - e

Given expressions, we learn:

 Q: .. cf

by

lap

+ Q

U)

(LV-UjG (T (6)

T-f

Oragh iUy - lUG (Tlt), (7)

G - large scale output

r,; j; e

resistor about.

Cs of equation (4) - taking into account overlapping;, 7 / and (8) we obtain: r, ... Ui () i.L1-, 0)

2

(8) including (2)

Then from the expression we get;

GT - 11 -OV

and I L f- e

Under the influence of this voltage through the second massable resistor 2 and: current flows

one

(ten)

Chapter 1, e C, is the conductivity of resistor 2, and § is the relative duration of the signal at control input 14.

Then the resistance of the element as a whole obeys the dependence I, 2, 2G

Mr. R,

where R is the resistance of the scale resistor 1, or when the condition R 1: 2G is fulfilled

Mr. Jje Invention Formula

An element with a controlled resistance containing a first scale resistor, the first terminal of which is the first signal signal terminal, the second terminal of the first scale resistor connected to the first end of the second scale resistor and the non-inverting input of the operational amplifier, the output of which is connected to the second end the second large-scale resistor to the first lining of the first smoothing capacitor and the first information output of the first key, the second information output of the first key is connected to the first vgoodu the third large-scale re

Yu

- J5 20 25 80 "

the control input of the first switch is connected to the output of the inverter, the input of which is the control input of the element, the second lining of the first smoothing capacitor is connected to the inverting input of the operational amplifier through a fourth scale resistor to the second signal output of the element, characterized in that In order to increase accuracy when controlling the average value of the resistance according to a quadratic law, a second switch, a second smoothing capacitor, and a fifth scaling {resistor, first turn The second mass resistor is connected via a second switch to the inverting input of the operational amplifier and to the first pin of the fifth scale resistor, the second pin of which is connected to the second pin of the third scale resistor and connected via the second smoothing capacitor to the zero potential bus; control of the input element

 Compiled by I. Zaitsev Editor S. Patrushev Tehred M. Khodanich Proofreader. Roshko

Order 2773/52 Circulation 671 Subscription

VNSHSHI USSR State Committee

for inventions and discoveries 113035, Moscow, Z-ZZ, Raushsk nab., d, 4/5

Production and printing company, Uzhgorod, st. Design, 4.

Claims (1)

Claim A controlled resistance element containing a first scale resistor, the first output of which is the first signal output of the element, the second output of the first scale resistor is connected to the first output of the second scale resistor and the non-inverting input of the operational amplifier, the output of which is connected to the second output of the second scale resistor, to the first the lining of the first smoothing capacitor and the first information output of the first key, the second information output of the first key is connected to the first output to the third scale resistor, the control input of the first key is connected to the inverter output, the input of which is the control input of the element, the second lining of the first smoothing capacitor is connected to the inverting input of the operational amplifier 'and through the fourth scale resistor to the second signal output of the element, and 10, in order to increase the accuracy when controlling the average value of the resistance according to the quadratic law, a second key, a second smoothing capacitor 15 and a fifth scale are introduced into it a resistor, the first output of the third scale resistor is connected through the second key to the inverting input of the operational amplifier and the first output of the fifth scale resistor, the second output of which is connected to the second output of the third scale resistor and connected through the second smoothing capacitor to the left potential bus 25, the control input of the second the key is connected to the control input of the element.