JPH06138186A - Method for testing printed circuit board-packaged circuit - Google Patents

Abstract

PURPOSE:To perform operation test simply by eliminating the need for preparing an exclusive printed circuit board testing device for each printed circuit board and by reducing the number of wirings between the printed circuit board and a measuring instrument. CONSTITUTION:A test signal generation means 4 for generating an operation test signal of a packaging circuit 2, a switching means 5 for selecting either the output of the test signal generation means 4 or the output of a timing generation circuit 3 and then supplying it to the packaged circuit 2, and an output selection means 7 for selecting any signal output a plurality of output signals of the packaged circuit 2 and then outputting it are provided on a printed circuit board 1, a switching means 5 is switched to a test signal generation means side for supplying the test signal generated by the test signal generation means 4 to the packaging circuit 2 on operation test of the packaged circuit 2, any signal out of output signals which are output from the packaged circuit 2 is selected by the output selection means 7 at this time, and then the selected output signal is measured by a measuring instrument 9 which is provided outside the printed circuit board.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for testing a printed circuit board mounted circuit.

[0002]

2. Description of the Related Art FIG. 3 is an explanatory diagram of a conventional method for testing a printed circuit board mounted circuit. In the figure, 50 is a printed circuit board, 51 is various electric circuits (hereinafter referred to as “mounting circuit”) such as ICs and electric parts mounted on the printed circuit board,
Reference numeral 52 is a printed circuit board test apparatus. In the conventional method for testing a printed circuit board mounting circuit, an operation test signal is applied from the test signal generator 53 of the printed circuit board test device 52 to the test input terminal 54 of the printed circuit board 50, and at this time, the output terminal 55 of the printed circuit board 50 outputs the test signal. The output signal to be connected is connected to the signal selector 26 of the printed circuit board testing device 22 using a large number of lead wires, and the signal selector 2 is selected from among the large number of output signals.
By selecting a desired signal in 6, the output state is observed by a measuring instrument such as the oscilloscope 27.

[0003]

In the conventional test method described above, there is a problem in that a dedicated printed circuit board test device 52 must be designed and produced and prepared for each different internal circuit of the mounting circuit 51. It was Further, there is a problem that a lot of wiring is required between the printed circuit board 50 and the printed circuit board testing device 52, which makes the test laborious.

The present invention has been made based on the above circumstances, and its purpose is to eliminate the need for preparing a dedicated printed circuit board testing device for each printed circuit board as in the conventional case, and to provide a printed circuit board and a measuring instrument. It is an object of the present invention to provide a test method for a printed circuit board mounting circuit, which requires only a small amount of wiring between the circuit boards and can easily perform an operation test.

[0005]

Means adopted by the present invention for solving the above problems will be described with reference to the principle diagram of FIG. In the figure, 1 is a printed circuit board, 2 is an electric circuit (mounting circuit) mounted on the printed circuit board 1, 3 is a timing generation circuit for normal circuit operation provided in the mounting circuit 2, and 4 is an operation test. Signal generating means for generating a test signal for the switching circuit, 5 is a switching means for selecting the output of the test signal generating means 3 during the operation test, 6 is an output terminal of the mounting circuit 2, and 7 is an output of the mounting circuit 2. Output selecting means for selecting a predetermined output signal from the output signals, 8 is a test output terminal, and 9 is a measuring device connected to the outside of the printed circuit board to observe the signal output from the test output terminal 8. The test signal generating means 4, the switching means 5 and the output selecting means 7 are provided on the same printed circuit board 1 as the mounting circuit 2.

[0006]

In normal times, the switching means 5 is the timing generation circuit 3
Connected to the side. Therefore, when the printed circuit board 1 is actually incorporated and used in an electronic device or the like, the internal mounting circuit 2 is supplied with a regular timing signal from the timing generation circuit 3, and the regular timing signal is supplied in accordance with the regular timing signal. It operates and outputs a regular output signal from the output terminal 6.

During the operation test of the printed circuit board, the switching means 5 is switched to the test signal generating means 4 side. This allows
A predetermined test signal for the operation test is supplied from the test signal generating means 4 to the mounting circuit 2. The mounting circuit 2 performs a predetermined test operation according to this test signal. Output selection means 7
Selects a predetermined signal from the plurality of output signals output from the mounting circuit 2 at this time and sends it to the test output terminal 8. The output signal sent to the test output terminal 8 is guided to the externally connected measuring instrument 9, and the output state is monitored to determine whether the mounted circuit 2 is normal or not.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram of an embodiment of the present invention.
In the figure, 10-1 to 10-n are circuits (circuits under test) such as ICs mounted on the printed board 1, 11
Is a timing generation circuit for generating timing signals for the normal operation of the circuits 10-1 to 10-n, and 12 is the circuit 1
A test signal generating circuit for generating a test signal for performing an operation test of 0-1 to 10-n, and a multiplexer (MPX) 13 for selecting a test signal generated by the test signal generating circuit 12 during the operation test. .

14-A and 14-B are circuits 10-1 to 10-10.
A multiplexer (MPX) for selecting and outputting a specified output signal from a plurality of output signals output by -n, 1
Reference numeral 5 is an input switching pin terminal for switching the input signal selected by the MPX 13 by inserting a setting pin, and 16 is MPX1.
Output selection pin terminals for selecting signals output from 4-A and 14-B by inserting setting pins, 17 are output terminals, and 18 is a test output terminal. All of these circuits are provided on the printed board 1.

Normally, the MPX 13 selects the timing generation circuit 11 side, and outputs the timing signals A and B output from the timing generation circuit 11 to the circuits 10-1 to 10-n.
To each. Circuits such as ICs 10-1 to 10-1
0n performs a predetermined operation according to the timing signals A and B. Then, the output signals A and B output from the circuits 10-1 to 10-n respectively correspond to the corresponding output terminals 17-1.
A, 1B to 17-nA, nB, and output to the outside.

When performing an operation test of the circuits 10-1 to 10-n, a measuring device 19 such as an oscilloscope is connected to the test output terminals 18-A and 18-B. Furthermore, by inserting a setting pin into the input switching pin terminal 15, MP
X13 is switched to the test signal generation circuit 11 side. Also,
By inserting a setting pin at a predetermined position of the output selection pin terminal 16, the output signal to be selected by the MPXs 14-A and 14-B is set.

When the test is started after the above setting, the predetermined test signals A and B are given from the test signal generation circuit 11 to the circuits 10-1 to 10-n through the MPX 13 and each circuit 10-. 1 to 10-n start the operation according to the test signals A and B.

By this test operation, each circuit 10-1 to 10-1
The output signals A and B output from 0-n are MPX14-
The output signals A and B of the circuit which are input to A and 14-B and set by the output selection pin terminal 16 are the test output terminals 18
-Sent to A, 18-B. Therefore, the measuring device 19
Observes the output signals sent to the test output terminals 18-A and 18-B and determines from the signal state whether the corresponding circuit in the printed circuit board 1 is operating normally. The output signals output from the MPXs 14-A and 14-B can be freely set by changing the pin insertion position of the output selection pin terminal 16.

Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications can be made according to the gist of the invention.

[0015]

As described above, according to the test method of the present invention, it is not necessary to input a test signal from the outside when the mounting circuit of the printed circuit board is tested, and the output from the mounting circuit is stored inside the printed circuit board. Since it is selected and output, it is not necessary to change the connection of the measuring instrument, and the operation test can be easily performed.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 1 printed circuit board 2 mounting circuit 3 timing generation circuit 4 test signal generation means 5 switching means 6 output terminal 7 output selection means 8 test output terminal 9 measuring instrument

Claims (1)

[Claims] 1. A test signal generating means for generating an operation test signal of a mounting circuit, and a switching means for selecting one of an output of the test signal generating means and an output of a timing generating circuit of the mounting circuit and supplying the selected circuit to the mounting circuit. And an output selection means for selecting and outputting an arbitrary signal from a plurality of output signals of the mounted circuit are provided on the printed circuit board, and during the operation test of the mounted circuit, the switching means is switched to the test signal generating means side. The test signal generated by the test signal generating means is supplied to the mounting circuit, and an arbitrary signal in the output signals output from the mounting circuit at this time is selected by the output selecting means, and the selected output signal is output to the outside of the printed circuit board. A test method for a printed circuit board mounted circuit, which is characterized by measuring with a prepared measuring instrument.