SU1285381A1 - Multichannel switching device for instrumentation equipment - Google Patents

Abstract

The invention relates to instrumentation engineering and can be used for switching measuring and control instruments to the outputs of tested integrated circuits. The purpose of the invention — improving accuracy — is achieved by eliminating the shunting effect of the channels through the switching elements of the measuring circuits. For this, each of the channel measurement circuits additionally contains two switching elements. The drawing shows the channels 1-1,.,., 1-6 switching, each of which contains switching elements 2,3 and 4, switching switching elements 5,6,7 and 8, inputs 9 and 10, input 11 of the screen circuit, the outputs 12 and 13, the output 14 of the screen circuit, the terminals 15, 16 and 17 of the chip under test. The proposed switch eliminates leakage currents through the open switching elements included in the measuring circuits of the switching channels. This removes the limitation in the direction of low currents when developing test equipment. 1 il. (L

Description

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The invention relates to instrumentation engineering and is intended for switching measuring and controlling means to the conclusions of test integrated circuits.

The purpose of the invention is to increase the switching accuracy by eliminating the shunting effect of the channels through the switching elements of the measuring circuits.

The drawing shows an electrical circuit of a six-channel switch.

The switch contains switching channels 1-1, .. ..., 1-6, each of which contains the first 2, second 3 and third 4 switching elements, the first 5, the second 6, the third 7 and the fourth 8 switching switching, the first 9 and the second 10 inputs, the input 11 of the screen circuit, the first 12 and second 13 outputs, the output 14 of the screen circuit, the first 15, the second 16 and the third 17 pins of the tested chip. Switching elements 2 and 3 are included in the measuring circuit of the channel, and element 4 - in the screen circuit. The closing contacts of the switching switching elements 5 and 7 are separately connected to inputs 9 and 10 of the corresponding measuring circuits of the switching channel; the closing clocks of the switching switching elements 6 and 8 are separately connected to the outlets 12 and 13 of the respective measuring circuits; the switching contacts of elements 5 and 6 are connected in series with the switching element 2 into the first measuring circuit, and the switching contacts ele2

to the second conclusion 16 of the tested IC. In this case, the switching elements of the 2–8 channels 1–1, 1–3, and 1–5 will be closed, thereby providing the connections between the measuring sources and the indicated IC outputs necessary for carrying out the measurement process. Via the formed communication channels, the signals of the IC are fed to the outputs of the IC, and the reverse are the measured signals that are the response of the IC to these influences. At the same time, information transfer is carried out with high accuracy, since the switch-by-action of the other switching channels: 1-2, 1-4, and 1-6 is excluded from the switch. The opening contacts of elements 5-6 and 7-6, connected to the input potential of the screen circuit equal to 5V, will also have a potential of 5 V. Since the closing contacts of elements 5-6 and 7-6 are connected to inputs 9-6 and 10- 6 corresponding measuring circuits connected directly to the source-meter, then a potential of 5 V will also be set at these contacts. Equal potentials at the contacts of switching elements 5-6 and 5-7 prevent leakage currents from flowing through them. On the opening contacts of elements 6-6 and 8-6, connected to the output potential of the screen circuit of the first source-meter, O V, 35 the potential O V is also set. Since the closing contacts of elements 6-6 and 8-6 are connected via channel 1- 3 commutation with the first source meter, then on these contacts

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Copies 7 and B included will also be installed in series.

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to the second conclusion 16 of the tested IC. In this case, the switching elements of the 2–8 channels 1–1, 1–3, and 1–5 will be closed, thereby providing the connections between the measuring sources and the indicated IC outputs necessary for carrying out the measurement process. Signals of action are received through the formed communication channels to the outputs of the IC, and back to the measured signals that are the response of the IC to these influences. At the same time, information transfer is carried out with high accuracy, since the switch-by-action of the other switching channels: 1-2, 1-4, and 1-6 is excluded from the switch. The opening contacts of elements 5-6 and 7-6, connected to the input potential of the screen circuit equal to 5V, will also have a potential of 5 V. Since the closing contacts of elements 5-6 and 7-6 are connected to inputs 9-6 and 10- 6 corresponding measuring circuits connected directly to the source-meter, then a potential of 5 V will also be set at these contacts. Equal potentials at the contacts of switching elements 5-6 and 5-7 prevent leakage currents from flowing through them. On the opening contacts of elements 6-6 and 8-6, connected to the output potential of the screen circuit of the first measuring source, equal to O, the potential O is also set. Since the closing contacts of elements 6-6 and 8-6 are connected through channel 1-3 switching with the first source meter, then on these contacts

Pb potential will also be installed.

with the switching element 3 to the second measuring circuit; the disconnecting contacts of elements 5 and 7 are connected to the input 11 of the screen circuit, and the disconnecting contacts of elements 6 and 8 to the output 14 of the screen circuit. The potentials of the screen circuits are determined by the output voltages of the measuring sources.

Multichannel switch works as follows.

Let, in accordance with the control conditions, the switch must provide the connection of the first source-meter with the output voltage OV to the first 15 and third 17 terminals of the IC under test, and the second source-meter with the output voltage 5V

Consequently, the leakage current will not flow through the switching switching element 676 and 8-6. Through the open switching elements 2-6, 3-6 and 4-6, leakage current will flow from the potential-shielded circuits of both sources of meters, but this current does not affect the switching accuracy, as it flows not through the measuring, but through the screen. Similarly, leakage currents through the open switching elements included in the measuring circuits of channels 1-2 and 1-4 are eliminated, and thus their shunting effect on the switching channels 1-1, 1-3 and 1-5 is excluded.

Thus, when using the proposed device,

leakage currents through open-circuit switching elements included in the measuring circuits of the switching channels, thereby removing restrictions towards measuring small currents in the development of test equipment,

Claims (1)

Invention Formula A multi-channel switch for instrumentation, consisting of interconnected switching inputs and outputs, each of which contains at least two switching elements, one of which is included in the screen circuit and the others in the measuring circuit, inputs and outputs, with on-screen and measuring circuits in each of the channels having the same potentials, characterized in that, in order to increase the switching accuracy by eliminating the shunting effect of the channels through the switching elements, Each of the measuring circuits of the channel additionally contains two switching switching elements, the closing contacts of which are separately connected to the input and output of the measuring circuit, respectively, the switching contacts are sequentially connected to the bases (Noah switching element, disconnecting contacts are separately connected to the input and output of the screen circuit responsibly.