SU905861A1 - Analogue storage device - Google Patents

Description

The invention relates to automation and computing devices, namely, static-type analog storage devices, and can be used to store an analog signal in control systems and information devices.

One of the main characteristics of devices for storing analog signals is the accuracy in the storage mode of the recorded signal, which is determined by the rate of change of the output voltage.

Known analog storage device containing an input operational amplifier, the output of which is connected through the load element to the bus of zero potential, and through the first key to the inverting input of this amplifier, a storage element, for example, a capacitor, one plate of which is connected to the bus of zero potential, output operational amplifier , covered by negative feedback, keys and bus input sggsha. In this case, the input signal bus is connected via a second switch to the inverting input of the input operational amplifier and the non-inverting input of the output operational amplifier, the output of which through the third switch is connected to another capacitor plate and the non-inverting input of the input operational amplifier whose output is connected to the inverting input of the output operational amplifier 1.

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A disadvantage of the known device is the low accuracy in the storage mode of the recorded signal, due to the discharge of the storage capacitor due to leakage currents of the switching key.

The closest to the proposed technical entity is an analog storage device containing a comparison node, the first

The 20 input of which is the input of the device, the second input is connected to the output of the integrator, the output of which is the output of the device, and the output of the comparison node via an amplifier is connected to the input of the key. In this case, the output of the switch is connected to the input of the integrator, which includes an operational amplifier and a capacitor introduced in feedback. In the storage mode of the recorded signal

the key is open and the voltage at the output of the integrator is equal to the voltage at the moment of opening the key 2.

The main disadvantage of the known device is its lack of accuracy in the signal storage mode, which is associated with a change in the output voltage caused by the discharge of a capacitor, due to the presence of a leakage current of the switch.

The purpose of the invention is to increase the accuracy of the device in the signal storage mode by reducing the rate of change in the output voltage of the current while eliminating the effect of leakage,

 The goal is achieved by the fact that in an analog storage device containing an integrator, the output of which is connected to the output of the device and to the first input of the comparison unit, an amplifier whose input is connected to the output of the comparison unit, the first key, the input of which is connected to the output of the amplifier, the second input the comparator unit is connected to the device input, and the zero-potential bus, a nonlinear element-i ment and a second key are introduced, the input of which is connected to the output of the first key and the input of the nonlinear element / output of the second key is connected to hydrochloric zero potential, the output of the nonlinear element connected to the input of the integrator.

The drawing shows a functional diagram of the proposed device.

It contains the unit of comparison 1, amplifier 2, keys 3 and 4, nonlinear element 5, integrator 6 and zero potential bus 7.

Comparison unit 1 can be made in the form of two resistors connected at the input of amplifier 2, for which any type of operational amplifier can be used. The keys 3 and 4 can be performed, for example, on field or bipolar transistors. Nonlinear element 5 includes inter-parallel-connected diodes. The integrator b (as in the well-known) may consist of an operational amplifier and a capacitor included in the feedback, and you can use amplifiers such as K544 UD1 or K140 UD8 as an operational amplifier.

The device works as follows.

The input signal is fed to one of the inputs of the comparison unit 1 and is compared with the feedback signal received at the other input from the output of the integrator 6. The error signal through the amplifier 2 is fed to the input of the key 4. Depending on the operating mode of the device, the input of the integrator 6 is nonlinear element 5

a signal is supplied either from the output of the key 3 (signal recording mode) or via the key 4 from the zero potential bus 7 (the storage mode of the recorded signal).

In the recording mode of the signal, the key 3 is closed, the key 4 is open, the signal from the output of the key 3 through the nonlinear element 5 is fed to the input of the integrator 6. The signal at the output of the device becomes equal to the input signal due to negative feedback from the output of the integrator 6 on, | Comparison unit input 1. In the signal recording mode, the voltage drop across the diodes of the nonlinear element 5 does not affect the output voltage value due to the performance of the amplifier 2 with a high gain. In the storage mode of the recorded signal, the key 3 is open the key 4 is closed, and the input of the nonlinear element 5 is connected via the key 4 to the zero potential bus 7. Thus, the leakage currents of the key 3 are diverted by the key 4 to the zero potential bus 7 and do not affect the voltage of the nonlinear element 5. The voltage of the nonlinear element 5 is equal to the bias voltage at the input of the integrator b and the balancing of its operational amplifier can be reduced to a value of the order of units of microvolts. The output voltage is remembered equal to the voltage at the moment of unlocking the key 3. The discharge current of the feedback capacitor of the integrator 6 is determined by the current flowing through the nonlinear element 5, and therefore does not depend on the leakage currents of keys 3 and 4 and is described by the expression

r.,

where d is the thermal current of the diode of the nonlinear element 5; UCM is the bias voltage at the input of integrator 6; k is the number of series-connected diodes; % - temperature potential

diodes.

As follows from the above expression, with a decrease in the bias voltage at the input of the integrator b, the discharge current of its capacitor decreases, as a result of which the rate of change of the output voltage decreases.

Claims (2)

In the specific implementation of the layout of the proposed technical solution, silicon diodes D 223B, operational amplifiers K140 UD8 and keys on field-effect transistors K284K41 were used. For such a circuit with the parameters UtM B, Zo 10 A, ff 2.5-10 V, the calculated value of the current flowing through the diodes, 4-10 A, corresponds to the discharge of the storage capacitor s 1 µF per Z4 MB for 10 minutes. Thus, the significant differences between the new set of features, the presence of a nonlinear element and a second key and new connections, make it possible to reduce the discharge current of the integrator capacitor by more than order of magnitude. Analog memory device containing an integrator, the output is connected to the output of the device and to the first input of the comparison unit an amplifier whose input is connected to the output of the comparison unit, the first key input of which is connected to the output of the amplifier, the second input of the comparison unit is connected to the input of the device, and a zero potential bus, which is based on the fact that, in order to improve the accuracy of the device, a nonlinear element and a second key are entered into it, the input of which is connected to the output of the first key and to the input nonlinear The second element, the second key, is connected to the zero-potential bus; the output of the nonlinear element is connected to the input of the integrator. Sources of information taken into account in the examination 1. The author's certificate of the USSR W 546939, cl. G 11 C 2-7 / 00, 1977. 2.T.Telbaum I.M. and others. 400 schemes for AVM. M., Energie, 1978, p. 126 (prototype).