JPH0291964A - Integrated circuit - Google Patents

Abstract

PURPOSE:To decrease the kinds of integrated circuit for constituting circuits by providing switching means for a plurality of logic circuits at the outside of each case. CONSTITUTION:In an integrated circuit 1, switches 2 and 3 and an outer terminal group 10 are provided at the outside of the case. Four logic circuits having the different functions are provided in the circuit 1. One of the four logic circuits is selected in response to the switching of the switches 2 and 3 and electrically connected to input terminals 12 and 13 and an output terminal 11. Therefore, many integrated circuits 1 are prepared beforehand, and the switches 2 and 3 are slidden and switched in correspondence with the applications at the time of mounting. In this way, the kinds of the integrated circuit to be prepared can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an integrated circuit, and more particularly to an integrated circuit mounted inside a computer or the like.

Yoshiejin 1 Traditionally, when realizing logic circuits used in computers, many types of integrated circuits (ICs) were mounted on printed circuit boards.
eoratedC1rcuit). Therefore, there is a drawback that it is very complicated to prepare the necessary integrated circuits in advance.

An object of the present invention is to provide an integrated circuit that can reduce the number of types of integrated circuits that must be prepared when realizing a logic circuit.

The integrated circuit of the present invention is an integrated circuit having a plurality of logic circuits inside a case and having an input terminal and an output terminal outside the case, wherein the plurality of logic circuits are selectively connected to each other. The device is characterized in that a switching means for electrically connecting the input terminal and the output terminal is provided outside the case.

1 pull 1 Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is an external view of an embodiment of an integrated circuit according to the present invention. In FIG. 1, an integrated circuit 1 according to an embodiment of the present invention is
Switches 2 and 3 and an external terminal group 10 are provided outside the case.

This integrated circuit 1 is provided with four logic circuits having mutually different functions. And switches 2 and 3
In response to the switching, one of the four logic circuits is selected and electrically connected to the input terminals 12 and 13 and the output terminal 11.

Therefore, a large number of integrated circuits 1 are prepared in advance,
By sliding the switches 2 and 3 according to the intended use, the number of types of integrated circuits that must be prepared can be reduced.

Next, the logic circuit inside the integrated circuit 1 will be explained using FIG. 2. FIG. 0 is a circuit diagram showing the internal configuration of the integrated circuit 1, and parts equivalent to those in FIG. In Figure 6, 21 and 25 to 32 are AND circuits, 2
2 is a NAND circuit, 20 and 23 are OR circuits, 24 is a NOR circuit, and 33 and 34 are inverters.

In a circuit having such a configuration, if both switches 2 and 3 are in an on state, only the output of AND circuit 25 among AND circuits 25 to 28 becomes high level. Then, one of the inputs of the AND circuit 29 becomes high level, so the output of the AND circuit 21 becomes the AND circuit 29 and the OR circuit 20.
appears at the output terminal 11 via. In other words, the accumulation port FI@1 in this case uses 12 and 13 as input terminals, and 1
It operates as an AND circuit with 1 as the output terminal.

Next, if the switch 2 is in the OFF state and the switch 3 is in the ON state, the output of the AND circuit 26 is set to a high level by the inverter 33. Then, one of the inputs of the AND circuit 30 becomes high level, so that the output of the NAND circuit '#122 appears at the output terminal 11 via the AND circuit 30 and the OR circuit 20. In other words, the integrated circuit 1 in this case has 12'EL and 1
It will operate as a NAND circuit with 3 as the input terminal.

Further, if the switch 2 is on and the switch 3 is off, the inverter 34 causes the output of the AND circuit 27 to go high. Then, one of the inputs of the AND circuit 1'131 becomes high level, so the output of the OR circuit #I23 passes through the AND circuit 31 and the OR circuit 20 to the output terminal 11.
appears in In other words, the integrated circuit 1 in this case is 12 and 1
It will operate as an OR circuit with 3 as the input terminal.

Furthermore, if the switches 2 and 3 are both off, the inverters 33 and 34 cause the output of the AND circuit 28 to go high. Then, one of the inputs of the AND circuit 32 becomes high level, so the output of the NOR circuit 24 appears at the output terminal 11 via the AND circuit 32 and the OR circuit 20. That is, the integrated circuit 1 in this case operates as a NOR circuit with input terminals 12 and 13.

The relationship between the states and operating functions of the switches 2 and 3 explained above is clearly shown in FIG. 3.

By switching the switches 2 and 3 as described above, the circuit operates as four types of logic circuits, so the number of types of integrated circuits that must be prepared in advance can be reduced.

In this embodiment, two switches are provided to selectively use one of the four types of logic circuits.
One type (for example, an AND circuit and an OR circuit) or one of five types of logic circuits may be used alternatively. In this case, the number of switches may be increased or decreased depending on the type.

Furthermore, although three of the external terminals are used in this embodiment, more terminals may be used.

Furthermore, in this embodiment, D I P (Dua
In the case of PGA (Pin Grid^) type integrated circuits, I have explained
It may be used for an integrated circuit (Rray) type integrated circuit, or a so-called hybrid IC.

As explained above, the present invention provides a switch in the case of an integrated circuit, and uses this switch to switch the internal logic circuit. This has the effect of reducing the number of circuit types.

[Brief explanation of the drawing]

FIG. 1 is an external view of an integrated circuit according to an embodiment of the present invention, and FIG.
This figure is a circuit diagram inside the integrated circuit of FIG. 1, and FIG. 3 is a diagram showing the relationship between switch states and operating functions. Explanation of symbols of main parts 1...Integrated circuit 2.3...Switch 11...Output terminal 12.13...Input terminal Applicant: NEC Corporation Company (1 other person)

Claims (1)

[Claims] (1) An integrated circuit having a plurality of logic circuits inside a case and an input terminal and an output terminal outside the case, the plurality of logic circuits being selectively electrically connected to the input terminals and the output terminals. An integrated circuit comprising a switching means for connection outside the case.