SU1005078A1 - Extremum voltage extraction device - Google Patents

Description

The invention relates to analog computing.

A device / built on operational amplifiers and a diode assembly is known, in which feedback is implemented by connecting an inverting amplifier to the output of a diode assembly, the signal from which is fed to non-inverting inputs of operational amplifiers ti3

The drawback of the device lies in the limited functionality (it is able to absorb only the maximum or, when changing the polarity of the diodes, only the minimum voltage).

The closest to the technical nature of the - proposed is a device in which the input signals act on the non-inverting inputs of the operational amplifiers, and the feedback signals are turned on to invert the inputs from the output of the diode assembly through resistors C2.

Its disadvantage also lies in the limited functional limitations;

The purpose of the invention is to expand the functionality by

selection of maximum and minimum signals and their differences.

The goal is achieved by the fact that a device for isolating extreme voltages, containing n operational amplifiers, noninverting the inputs of which are connected through appropriate scale resistors to the corresponding inputs of the device, inverting inputs are connected to the output of the device, and the outputs are connected to the output devices through the corresponding commutation diodes, contains 2p additional large-scale resistors and a shunt resistor connected in parallel one In this case, the inverting inputs of the operational amplifiers are connected through the corresponding additional large-scale resistors to the corresponding additional inputs of the device, while the non-inverted inputs of the operational amplifiers are connected through the appropriate additional large-scale resistors with a zero potential bus.

The drawing shows a diagram of the device with six inputs.

It contains operational amplifiers 1, 2 and 3, the number of which in the end case is determined by the number of inputs (switching signals, switching, diodes 4, 5 and 6, scale resistors 7-15, scale resistors 16-18 and shunt resistor 19. Input voltage and u and j and u4, ug and and and are fed to the inputs of amplifiers 1-3, which have transmission coefficients respectively K, K, K, determined by the scale resistors.

I

The device works as follows.

Suppose that the voltage difference applied to the non-inverting and inverting inputs of amplifier 1 is positive, and its magnitude is such that the output of amplifier 1 is set to # voltage, (). higher than the voltages at the outputs of other amplifiers. Diode 4 is open at the same time, while amplifier 1 is covered by feedback. The feedback circuit of other amplifiers is open, since their invertirugation inputs receive a higher voltage K (() from the output of the device. This comes to saturation of amplifiers 2 and 3 and locking diodes 5 and b.

Suppose now that the voltage difference is negative, and the voltage K2 (id-out) is greatest. Before the onset of the steady state, all the diodes are covered by the output signals of the respective amplifiers. Amplifier 3 is feedback-fed through resistors 18 and 19, therefore, the output voltage of the device decreases to a value, ((i (, - U But as soon as it is equal to the minimum negative voltage Ui,), diode 5 opens, closes the feedback circuit of amplifier 2, further decreases the voltage at the output of the device. stops, and amplifier 3 goes into saturation

Thus, the voltage at the output of the device for isolating extreme stresses in the presence of

its inputs are signals u, uj. 2 and Uy,, formed in accordance with the expression

and - maxCKi (IJi-U,),), ... ... K (and, - Ui.

 In the private, most practical cases, when the resistances of the scale resistors are equal, and the corresponding inputs are connected to the Zero potential bus, the output voltage of the device can be determined by one of the following expressions

U - max (U-, Ud, .... UjJ; D 3, o;

and max (-U4 ,, -and ,, (J).

with qf- ... and o.

As can be seen from the above expressions, the proposed device is able to separate the maximum and minimum values of the input signals. The device performs selection operations with both non-inverted input signals and non-inverted input signals, and, therefore, has broader functionality compared to the prototype.

These capabilities of the device determine a number of new applications. Supplying, for example, the input voltage simultaneously to 1 and 4 or 2 and 3 inputs (and. And either Uj), we obtain at the output of the device a full-wave rectification of the input voltage. Similar to the commutator following inputs, we have at the output of the device the maximum of the modules of the input signals.

In addition to traditional use, due to the wide functionality on the basis of the proposed device, measuring transducers of alternating voltage into a constant level of average free-range and amplitude values, sampling-storage devices, level discriminators, comparators, zero detectors, phase-sensitive detectors can be built. , amplitude modulators, demodulators, phase-to-voltage converters, etc.

When changing the polarity of the diodes, the device performs the operation

and t1pGk (i.-i) i K (UA-U); ...

n (Uvv, -V1)

The outputs of the operational amplifiers can be used to indicate the location of an extremum by the presence of a signal at this output that is different from the saturation voltage of the amplifiers.

The proposed device for the isolation of extreme stresses is easily realized on the basis of modern elemental base, including the integral design.

Claims (2)

1. Author's certificate of the USSR 785782, cl. G 01 R 19/30, 1978. 2. For Japan Japan if49-44776, cl. G 06 G 7/12, publ. 1974 (prototype).