SU1195306A1 - Apparatus for testing threshold switches with s-shape volt-ampere characteristic - Google Patents

Description

The invention relates to a measurement technique and is intended to measure and control parameters of two-terminal networks with a 5-shaped volt-ampere characteristic (IVC), in particular for testing threshold switches made on the basis of amorphous and glassy semiconductors, transition metal oxides, etc. ¹⁰

The purpose of the invention is the expansion of functionality.

Figure 1 presents the block diagram of the device} in figure 2 - timing diagrams. devices explaining the operation of the device; fig.Z - control unit, an example of execution

A device (see fig, ΐ) for examining threshold switches with a 5-volt-ampere characteristic of a ^ -containing voltage generator 1, two terminals 2 and 3 for connecting a test switch, the first terminal 2 for connecting which is connected to the input, repeat - 25 For 4 voltages, a control unit 5, a counter 6 and a display unit 7, in addition, a controlled divider 8, a comparator 9, a constant voltage source 10, then a 30-pinch resistor 11 are entered into it, while the controlled divider 8 is made as ballast resistor; 12, the load resistor 13 and the key 14, the key I4 input is connected to the first input of the controlled divider 8, the second input of which is connected to the first output of the ballast resistor 12, the second output of which is connected respectively to the first output of the load resistor 13 and the output of the key 14, the second output of which is connected to the common bus; the second output of the load resistor 13 is connected to the output of the controlled divider 8, and the first output of the voltage generator 1 is connected to the second input of the controlled divider 8, the output of which is connected to the first terminal oh 2 for connecting the test switch; the second terminal 3 for connecting which is connected respectively to the first input of the display unit 7 and the first terminal of the collector resistor 11, the second terminal of which is connected to the common bus 55, the second terminal 3 to connect the switch under study is connected to the first input

the comparator 9, the second input of which is connected to the output of the DC voltage source 10, the output of the comparator 9 is connected to the first input of the block ' ¹ . 5, the second input of which is connected to the second output of the voltage generator 1, the second input of the controlled divider 8 is connected to the output of the control unit 5, which is connected to the counter input, the second input of the display unit 7 is connected to the output of the voltage follower 4.

Schematic diagram of the control unit 5 (smf.Z). The control unit 5 is assembled on four 15-18 logical elements 2I-NOT and structurally consists of a CS-trigger and a delay circuit. The KS-trigger is assembled on the first 15 and second 16 elements 2I-NOT, the delay circuit is implemented on the third 17 and fourth 18 elements 2I — NOT using a timed KS chain. To the trigger input is connected to the output of the comparator 9, the 5-input receives a synchronization signal from the generator 1. The output of the K5-trigger is connected through a delay circuit with the input of the key 14 and the counter 6.

The key 14 is a transistor, the collector of which is connected to the point of connection of the ballast and load resistors, the emitter is connected to the common bus, and the signal from the control circuit 5 is fed to the base through the limiting resistor.

The device works as follows.

The test switch is connected to terminals 2 and 3 for connecting the test device.

The inverting input of the comparator 9 is supplied from the source 10 with a constant positive reference voltage _; living

and = ΙΚ,

where K is the value of the current collection slave · torus 11;

I - required cut-off current.

The device allows you to observe any part of the 5-VAC 'on the screen of the oscilloscope, starting with the selected current value. This current value is set at the non-inverting (+) input of the voltage comparator 9 by the source 10 pos1 195306

four

3

voltage constant. (see Fig.1), the output of the comparator 9 (Fig. 2 dia. e) sets the potential "I ¹ '. The generator 1 generates a sawtooth voltage (Fig, 2 dia. a}. at time ₍ the switch under test turns into low-impedance state, the current through the collector resistor 1] increases, reaches a predetermined value and the level "O" appears at the output of the comparator 9

(Fig.2 Diag * e, time. By starting the oscilloscope sweep with the ”1/0” front from point e, one can observe the voltage or the current flowing through the switch under study at any time determined by the setting of the comparator actuation current.

To exclude a long stay under the current of the switch, which is in a conducting state, key 14, after an adjustable time

after switching, it blocks the voltage supply from the generator 1 to the switch under study (figure 2 diag. B, time ίζ.).

To do this, the output of the control unit 5 at the time point ί ₂ appears potential ”1”, opening transistor switch 14 (FIG. 2 diag. C) '. When this voltage on the collector resistor 11 drops and at the output of the comparator 9 again sets the potential ”1", (figure 2 dia. F.,. Time.

The key control unit 5 returns to the initial position "0" when the clock pulse arrives from generator 1, generated at the beginning of each "saw" (Fig. 2, Diagram g and H, (time "C). The voltage plots at point b repeat the view in FIG. .2 diag. B. The voltage at the point is a constant positive.

The value of the cutoff current is determined by the conductivity of the switch in the high resistive state and the instant of the beginning of the observation on the oscillograph screen of the section with the SLM.

The magnitude of the delay time Cg'C-Dc is determined by the study of the influence of the switch duration of the switch in the conducting state under current on the switching parameters and the duration of observation from the SLM on the oscilloscope screen.

The device is technically implemented as follows.

An oscilloscope sweep generator, together with a voltage amplifier, was used as a sawtooth * voltage generator to obtain a saw amplitude of up to 160 V.

Ballast resistor 4.7 com., Current collector resistor 100 Ohm. The voltage comparator K521SAZA. A constant reference voltage is supplied in the range of 0.01–1 V, which corresponds to cut-off currents of approximately Ό, 1–10 mA.

The control unit 5 is assembled on a single case of the K530LAZ chip, which includes four 2I-NOT elements.

The key 14 is implemented on the transistor KT605A with a resistor 2 com, in the base circuit.

The expansion of the functionality in the invention in comparison with the prototype lies in the possibility of detecting with the help of, for example, an oscilloscope of a 5-shaped I – V capacitance section with an ODS. This is achieved through the use of a current collector resistor and voltage comparator with an adjustable response threshold ', which makes it possible to observe the section with the ODS from different convenient times corresponding to different current values passing through the switch under test. Using the proposed device, it is possible to study the effect on the switch parameters of the energy released in the switching process due to a change, thanks to the delay unit included in the key control unit, of the time spent under the switch current in the conducting state.

1195306

@ 128. one

1195306

Claims (1)

DEVICE FOR RESEARCH OF THRESHOLD SWITCHES WITH 5-VOLT-AMPERAL CHARACTERISTIC, containing a voltage generator, two terminals for connecting the investigated threshold switch, the first terminal for connecting which is connected to the input of the voltage follower, control unit, counter and display unit, a LED, and a display unit, a pendant. This is due to the fact that, in order to expand its functionality, a controlled divider, a comparator, a DC voltage source, a collector resistor are introduced into it, and the controlled divider is En as a ballast resistor, load resistor and key, the key input is connected to the first input of a controlled divider, the second input of which is connected to the first the output of the ballast resistor, the second output of which is connected respectively to the first output of the load resistor and the first output of the key, the second output of which is connected to the common bus, the second output of the load resistor is connected to the output of the controlled divider, the first output of the voltage generator is connected to the second input of the controlled divider, output which is connected to the first terminal for connecting the threshold switch under study, the second terminal for connecting which is connected respectively to the first input of the block display and the first output of the collector resistor, the second output of which is connected to the common bus, the second terminal for connecting the threshold switch under study is connected to the first input of the comparator, the second input of which is connected to the output of the DC voltage source, the output of the comparator is connected to the first input of the control unit, the second input of which connected to the second output of the voltage generator, the second input of the controlled divider is connected to the output of the control unit, which is connected to the input of the meter, the second input of the unit Superimpose connected to the output repeat * body voltage 1 1195306 2