RU164152U1 - DEVICE FOR FORMING AN INSTANT VOLTAGE VALUE SAMPLE - Google Patents

Abstract

A device for sampling an instantaneous voltage value, comprising: an operational amplifier (op amp); a clock pulse generator, which is connected through a logic inverter to the control input of the second key, and through a pulse shaper is connected to the input of the unit to the single state of the trigger, the input to the zero state of which is connected to the output of the comparator; the trigger output is connected to the control input of the first key; the input voltage source, through the first resistor and the first key, is connected to the first terminals of the second key and the storage capacitor, characterized in that the second, third and fourth resistors are introduced into the device, the first terminal of the second resistor connected to the first terminals of the second key and the storage capacitor, the second output of the first key and the non-inverting input of the op-amp; the second output of the second resistor is connected to the non-inverting input of the comparator, the output of the op-amp, the output of the device and, through the fourth resistor, with the inverting input of the op-amp and the second output of the third resistor, the first output of which is grounded; the inverting input of the comparator is connected to the input voltage source and the first output of the first resistor; the second terminals of the second key and the storage capacitor are grounded.

Description

The technical field to which the utility model relates.

The utility model relates to electrical engineering, in particular to devices for generating samples of instantaneous voltage values.

State of the art

A device for sampling and storage containing an analog key, two operational amplifiers, a storage capacitor, a feedback resistor, a limiting resistor, two on-board diodes (Zhavoronkova M.S., Bondar S.N. Development of a high-speed device for sampling and storage with increased accuracy / / Methods and technical means of increasing the efficiency of the use of electrical equipment in industry and agriculture: collection of scientific papers based on the materials of the 75th scientific and practical conference of the Electric Power Department SSAU. - Stavropol: AGRUS, 2011.S. 102, Fig. 3). A feature of this device is the fulfillment of the conditions:

where τ _p is the gating interval (sampling);

τ _s - charge time of the storage capacitor.

The disadvantage of this device is the occurrence of an error in the sampling of the analog voltage, due to the fact that the input voltage changes during the sampling interval (sampling), which leads to an ambiguity in the determination of the output voltage (within Δu (Fig. 1)), since it depends on the gate time. Moreover, the noted error is fundamentally unrecoverable due to the fulfillment of condition (1).

A device for sampling and storage containing a non-inverting voltage amplifier, the input of which is simultaneously the information input of the device for sampling and storage and the second input of the comparison circuit, the first input of which is connected to the output of the repeater on the operational amplifier and the output of the device for sampling and storage; the output of the comparison circuit is connected to the S-input of the trigger, the R-input of which serves as the control input of the sampling and storage device; the trigger output is connected to the control input of the analog switch, the input of which is connected to the output of a non-inverting voltage amplifier, and the output is connected to the inputs of the storage capacitor and repeater on the operational amplifier; the comparison circuit contains two comparators and an OR-NOT circuit, the inputs of which are the outputs of the comparators, and the output serves as the output of the comparison circuit; the opposite inputs of the comparators are interconnected and with the inputs of the comparison circuit (patent RU 63623, IPC H03K 17/60).

The disadvantage of this device is the low accuracy of storing the magnitude of the voltage of the input signal.

The closest analogue is the prototype of the claimed technical solution is a device for sampling instantaneous voltage values (patent RU 2230376, IPC G11C 27/02).

A device for sampling the instantaneous voltage value contains an operational amplifier (op-amp), the non-inverting input of which is grounded, and the inverting input is connected to the input voltage source through the first switch and resistor, and a storage capacitor is connected in the negative feedback circuit of the op-amp, in parallel with which the second switch is connected, and the output of the device is the op-amp output, which is connected through an analog inverter to the non-inverting input of the comparator, whose inverting input is connected to the input source voltage, and the output is with the input to the zero state of the trigger, the output of the latter is connected to the control input of the first key, and the input to the single state of the trigger, through a pulse shaper, is connected to the output of the clock generator, which is connected to the control input via a logic inverter second key.

Thus, in the prototype, the sampling of the instantaneous voltage value is carried out by an inverting integrator (made using an op-amp, a resistor with a resistance R, and a storage capacitor with a capacity of C), with a frequency response (2)

which is connected through an analog inverter (AI) to the non-inverting input of the comparator, whose inverting input is connected to the input voltage source. That is, the relation (3) holds

where ξ _AI is the error of signal conversion by an analog inverter

- напряжение на входе устройства в момент времени завершения выборки;

- voltage at the input of the device at the time of completion of sampling;

- напряжение на выходе устройства в момент времени завершения выборки, определяемое выражением (5)

- the voltage at the output of the device at the time of completion of the sample, defined by the expression (5)

- напряжение на входе аналогового инвертора в момент времени завершения выборки;

- voltage at the input of the analog inverter at the time of completion of sampling;

- напряжение на выходе аналогового инвертора в момент времени завершения выборки.

- voltage at the output of the analog inverter at the time of completion of sampling.

The disadvantages of this device are:

- polarity inversion of the formed sample of the instantaneous voltage value of the input signal;

- low accuracy of remembering the voltage value of the sample module input signal;

- a large value of the sampling time Δt _sampling .

Utility Model Disclosure

The technical result that can be achieved using the proposed utility model is to reduce the value of the sample time.

The technical result is achieved by the fact that in a device for forming a sample of an instantaneous voltage value comprising: an operational amplifier (OA); a clock pulse generator, which is connected through a logic inverter to the control input of the second key, and through a pulse shaper, connected to the input of the unit to the single state of the trigger, the input of the zero state of which is connected to the output of the comparator; the trigger output is connected to the control input of the first key; the input voltage source, through the first resistor and the first key, is connected to the first terminals of the second key and the storage capacitor, the second, third and fourth resistors are introduced, wherein: the first terminal of the second resistor is connected to the first terminals of the second key and the storage capacitor, the second terminal of the first key and non-inverting input of the op-amp; the second output of the second resistor is connected to the non-inverting input of the comparator, the output of the op-amp, the output of the device and, through the fourth resistor, with the inverting input of the op-amp and the second output of the third resistor, the first output of which is grounded; the inverting input of the comparator is connected to the input voltage source and the first output of the first resistor; the second terminals of the second key and the storage capacitor are grounded.

Brief Description of the Drawings

In FIG. 1, 3 are timing diagrams explaining the operation of the device.

In FIG. 2, a functional diagram of a device for sampling an instantaneous voltage value is shown.

In FIG. 4, a functional diagram of a non-inverting integrator is presented based on a two-terminal network with negative input resistance.

Utility Model Implementation

A device for sampling the instantaneous voltage value contains an input voltage source 1, op-amp 2, a first key 3, a first resistor 4, a storage capacitor 5, a second key 6, a second resistor 7, a comparator 8, a clock generator (GTI) 9, a logical inverter 10 , pulse shaper 11, trigger 12, third resistor 13, fourth resistor 14, wherein: the non-inverting input of the op-amp 2 is connected, through the first switch 3 and the first resistor 4, with the output of the input voltage source 1 and the inverting input of the comparator 8, with the first outputs of the second key 6 and a storage capacitor 5, as well as through the second resistor 7, with a non-inverting input of the comparator 8, the output of the op-amp 2, the output of the device and, through the fourth resistor 14, with the inverting input of the op-amp 2 and the second output of the third resistor 13, the first output of which grounded; the second terminals of the second key 6 and the storage capacitor 5 are grounded; the output of the clock generator 9, through the logical inverter 10, is connected to the control input of the second key 6, and through the pulse shaper 11, is connected to the input of the unit to the single state of trigger 12, the input of the zero state of which is connected to the output of the comparator 8; the trigger output 12 is connected to the control input of the first key 3.

The operation of the device is illustrated by timing diagrams (Fig. 3), which show:

- output voltage u ₉ GTI 9 (Fig. 3A);

- the input voltage of the device u _I , the output voltage u ₂ OS 2 (Fig. 3B);

- output voltage u _{10 of the} logical inverter 10 (Fig. 3B);

- output voltage u _{8 of the} comparator 8 (Fig. 3d);

- output voltage u _{12 of the} trigger 12 (Fig. 3d);

- the output voltage u ₁₁ of the pulse shaper 11 (Fig. 3E).

A device for sampling an instantaneous voltage value operates as follows.

The GTI 9 generates rectangular pulses (Fig. 3a) that control the operation of the device. Consider, for example, the i-th interval of the device, starting at time t _i (Fig. 3). The output voltage of the GTI 9 through the logical inverter 10 is supplied, firstly, to the control input of the second key 6, and in the time interval [t _i ; t _{i + 0.5} ] this voltage is zero (Fig. 3c), so the second key 6 open, and secondly, to the input of the pulse shaper 11, which generates a short pulse (Fig. 3e), which sets the trigger 12 to state "1" (Fig. 3d), since it is fed to the input of the asynchronous installation of the trigger in a single state. This output signal of the trigger 12 is fed to the control input of the first key 3, which closes at time t _i .

The input voltage u _in (Fig. 3b) from the input voltage source 1 (Fig. 2) is supplied to a non-inverting integrator (Fig. 4), made on the basis of a two-terminal device with negative input resistance (Design of electronic devices on integrated circuits / Ed. C. Y. Shatz - M .: Sov. Radio, 1976, 312 pp. S. 158-163, Fig. 4.23, Fig. 4.24) consisting of OU 2, a storage capacitor 5 and resistors 4, 7, 13, 14.

Due to the need to fulfill condition (6)

where R ₍₄₎ , R ₍₇₎ , R ₍₁₃₎ , R ₍₁₄₎ are the resistances of the resistors, respectively, 4, 7, 13 and 14,

determining the mode of optimal functioning of the integrator, its negative resistance. [Electronic resource] http://www.gaw.ru/html.cgi/txt/doc/op/funop_10_6.htm (accessed: 09/22/2015))

The output voltage of the OS 2, in the interval [t _i ; t _select ] changes in accordance with the expression (8) (Fig. 3b)

and fed to the comparator 8, to the other input of which the input voltage is also supplied.

(время выборки) (фиг. 3б),For u ₂ <u _in, comparator 8 is in the state “0” (Fig. 3c) and does not affect the operation of trigger 12. At the time

(sampling time) (Fig. 3b),

what is fixed by the comparator 8 in the form of the presence of a voltage drop of "0-1" at its output, the trigger 12 is transferred to the state of the logical "0" (Fig. 3d), which leads to the disconnection of the first key 3.

, т.е. производится формирование выборки мгновенного значения. Время хранения равно

(фиг. 3б), в течение которого можно использовать полученную информацию о значении выборки в соответствии с решаемыми задачами. В течение интервала времени [t_i+0,5; t_i+1] второй ключ 6 замыкается (на его вход управления поступает единичный сигнал с выхода логического инвертора 10 (фиг. 3в)) и конденсатор 5 разряжается, а в момент времени t_i+1 (фиг. 3) начинается следующий цикл.As a result, the capacitor 5 stores the voltage, which is equal to the instantaneous value of the input voltage at a time

, i.e. sampling of instantaneous value is performed. Storage time is

(Fig. 3b), during which it is possible to use the obtained information about the value of the sample in accordance with the tasks being solved. During the time interval [t _{i + 0,5} ; t _{i + 1} ] the second switch 6 is closed (a single signal from the output of the logic inverter 10 (Fig. 3c) is supplied to its control input) and the capacitor 5 is discharged, and at the time t _{i + 1} (Fig. 3) the next cycle begins.

Thus, in the case of the proposed device:

- taking into account expressions (5) and (8), the statement on reducing the value of the sampling time is valid, namely:

- taking into account expressions (3) and (9), the statement on improving accuracy when forming a sample of the instantaneous voltage value, with a polarity corresponding to the polarity of the input signal, is valid.

Claims (1)

A device for sampling an instantaneous voltage value, comprising: an operational amplifier (op amp); a clock pulse generator, which is connected through a logical inverter to the control input of the second key, and through a pulse former is connected to the input of the unit to the single state of the trigger, the input to the zero state of which is connected to the output of the comparator; the trigger output is connected to the control input of the first key; the input voltage source, through the first resistor and the first key, is connected to the first terminals of the second key and the storage capacitor, characterized in that the second, third and fourth resistors are introduced into the device, the first terminal of the second resistor connected to the first terminals of the second key and the storage capacitor, the second output of the first key and the non-inverting input of the op-amp; the second output of the second resistor is connected to the non-inverting input of the comparator, the output of the op-amp, the output of the device and, through the fourth resistor, with the inverting input of the op-amp and the second output of the third resistor, the first output of which is grounded; the inverting input of the comparator is connected to the input voltage source and the first output of the first resistor; the second terminals of the second key and the storage capacitor are grounded.

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