JPS62293736A - Integrated circuit with test circuit - Google Patents

Abstract

PURPOSE:To test the inside of a circuit by mounting at least one of a test series-signal formation circuit enabling an output to the outside of the circuit and generating a digital output from a predetermined pattern or a test decision circuit, to which a prescribed pattern signal from the outside of the circuit is inputted and which compares with the pattern signal with a reference signal and decides it, and connecting each circuit. CONSTITUTION:The insides of integrated circuits contain a test series-signal formation circuit 1, a test object circuit 2 and a test-result decision circuit 3. The test circuits 1, 3 are used for testing the insides of the integrated circuits, an output from the test series signal formation circuit 1 outputting the serial or parallel series signal of the predetermined pattern is outputted to an output terminal 11 for the integrated circuits, and an input signal from an input terminal 10 is employed as an input to the test-result decision circuit 10. Consequently, the insides and outsides of the integrated circuits can be tested. The integrated circuit 21 with the test-series formation circuit 1 and the integrated circuit 23 with the test-result decision circuit 3 are used, and the integrated circuit 22 inserted between the circuits 21 and 23 is tested.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an integrated circuit having a test circuit inside the integrated circuit.

[Conventional technology]

Conventionally, integrated circuits having this type of test circuit have been equipped with a mechanism for testing the internal operation of the integrated circuit.

[Problem that the invention seeks to solve]

In the conventional integrated circuits mentioned above, only the internal operation of the integrated circuit is tested, so the calculation results on the integrated circuit are
There is a problem in that it is not possible to test whether accurate signal values are being propagated to the output terminal, and for integrated circuits that do not have a test circuit, it is difficult to test using test equipment external to the circuit or under actual usage conditions. Without it, there was a drawback that the test could not be performed.

An object of the present invention is to provide an integrated circuit with a test circuit which eliminates these drawbacks and allows testing of the inside of the circuit.

[Means for solving problems]

The configuration of the integrated circuit with a test circuit of the present invention includes a test series signal generation circuit that enables output to the outside of the circuit and creates a predetermined pattern of digital output, and a predetermined pattern signal inputted from outside the circuit. The present invention is characterized in that it includes at least one of a test determination circuit that performs comparison or determination with a reference signal, and by connecting these circuits, a circuit test can be performed.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. This embodiment includes a test series signal generation circuit 1, a circuit under test 2,
A test result determination circuit 3 is included in the integrated circuit. These test circuits 1 and 3 are used to test the inside of the integrated circuit, and output the output of the test sequence signal generation circuit 1, which outputs a serial or parallel sequence signal of a predetermined pattern, to the output terminal 11 of the integrated circuit. , the input signal from the input terminal 10 is input to the test result determination circuit 10. This makes it possible to perform internal and external tests on the integrated circuit.

FIG. 2 is a block diagram of an example of testing a circuit using the integrated circuit of this embodiment. An integrated circuit 21 having a test sequence generation circuit 1 and an integrated circuit 23 having a test result determination result 3 are used to test an integrated circuit 22 inserted between them.

FIG. 3 is another block diagram of the test method using the integrated circuit according to this embodiment. Integrated circuit test sequence generation circuit 1
The integrated circuit 31 is connected to the test result determination circuit 3 via external wiring 32 of the integrated circuit 31 . This makes it possible to directly test the signals propagating to the input/output terminals.

〔Effect of the invention〕

As explained above, the present invention allows signals to be normally propagated to the input/output terminals by assigning the input of the test result determination circuit to the output terminal of the integrated circuit of the test sequence generation circuit as well as to the input terminal of the integrated circuit. This makes it possible to test whether the Also,
It is possible to test not only the inside of an integrated circuit but also the outside of the integrated circuit. By using the test circuit inside the integrated circuit as a test circuit outside the integrated circuit, there is also the effect that the entire test circuit can be reduced in size.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG.
The figure is a block diagram of a second-side test circuit using the integrated circuit of this embodiment. 1... Test sequence generation circuit, 2... Test target circuit, 3
...Test result judgment circuit, 10...Input terminal, 11.
...Output terminal, 21...Integrated circuit having test sequence generation circuit, 22...Integrated circuit without test circuit, 23...
- Integrated circuit having a test result determination circuit, 31... integrated circuit, 32... external wiring. Figure 1

Claims (1)

[Claims] Inside the integrated circuit, there is a test series signal generation circuit that enables output to the outside of the circuit and creates a digital output of a predetermined pattern, and a test judgment circuit that inputs a predetermined pattern signal from outside the circuit and compares it with a reference signal or makes a judgment. 1. An integrated circuit with a test circuit, characterized in that the integrated circuit includes at least one of the above circuits, and is capable of performing a circuit test by connecting each of these circuits.