JPS59231459A - Testing apparatus - Google Patents

Abstract

PURPOSE:To rapidly test the DC characteristics of a low current consumption type electronic circuit such as a C-MOS type semiconductor integrated circuit, by applying predetermined voltage to a circuit to be tested. CONSTITUTION:The output of a test power source Ei is applied to a circuit 10 to be tested through a switching circuit S1, a resistor R and a testing connection cable 30 and the electrical state of the circuit 10 to be tested is observed by the voltage measuring means 22 and a current measuring means 24 of a testing apparatus 20. The test power source Ei temporarily outputs high voltage Vh in the initial stage and a time is controlled by a timing circuit TM. The speed of the charging to a capacity Cf belonging to the connection cable 30 is accelerated and, directly after said voltage Vh is returned to usual testing voltage Vi, a measurable state is brought about and a testing time is shortened to a large extent.

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to measurement technology and technology that is particularly effective when applied to electronic circuit testing, such as 0-M
The present invention relates to a technique that is effective for testing low current consumption type electronic circuits such as OS (complementary-metal-insulator-semiconductor) type semiconductor integrated circuits. [Background Art] The present inventor has developed the following technology regarding measurement technology, particularly testing technology for low current consumption electronic circuits such as C-MO8 type semiconductor integrated circuits. That is, it has a test power supply that generates a predetermined voltage for testing, and the circuit under test is supplied with the test voltage from the test power supply.
When we measure the electrical characteristics of the circuit under test by applying pressure to the An example of an apparatus for testing the electrical characteristics of a low current consumption type electronic circuit such as a 0-MO8 type semiconductor integrated circuit is shown. The test apparatus 20 includes a test power supply Et-resistor R, a switching circuit S1, a voltage measuring means 22, a current measuring means 24, and the like. Test power supply) y+ generates a constant test voltage v1. This voltage Vi passes through the switching circuit S1 and the resistor R and is output to the test terminal TP, and is then passed through the test connection cable 30 and applied to the terminal under test of the circuit under test 10. , the electrical state of the circuit under test 10 is observed by the voltage measuring means 22 and current measuring means 24 of the test apparatus 20. FIG. 2 shows an example of the operation of the test apparatus 20. The test voltage Vi is clamped in advance to a predetermined voltage Vi depending on the type of circuit under test and the content of the test. The voltage is applied to the circuit under test 10. As a result, some circuit voltage Vx can be observed from the test terminal TP on the test device 20 side, depending on the electrical state of the circuit under test. A certain circuit current Ix depending on the electrical state of the circuit under test 10 is observed from both ends of the resistor R on the test device 20 side.In this way, from 1 to ゛C, the observed voltage VX or current Ix block; H, the electrical characteristics of the circuit under test 10, especially i
``■Popularity can be measured.Then, the circuit under test 1
A test for 0 is performed. However, in this technique, the parasitic capacitance between the test device 20 and the circuit under test 10, especially the device 20 and the circuit 1
Due to the parasitic capacitance of the connection cable 30 between
Row Al: When a problem arises that it is not possible to
The inventor has clearly determined that this is the case. [Objects of the Invention] One object of the present invention σ) is to provide a test device that can perform tests in a short time. One object of the present invention is to provide a test technique that allows testing to be performed in a short time. It is also an object of the present invention to carry out measurements immediately after application of the test voltage.

[It provides testing technology that makes it possible to Furthermore, one object of the present invention is to provide a test technique that can shorten the time required to apply a test voltage for measurement. The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings. [Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows. That is, by applying a predetermined voltage to the circuit under test, the purpose of quickly testing the DC characteristics of the circuit under test is achieved. [Embodiments] Hereinafter, typical embodiments of the present invention will be described with reference to the drawings. In addition, the same or corresponding parts are indicated by the same reference numerals in the drawings. First, FIG. 3 shows an embodiment of the maintenance test device according to the present invention. The test device 20 shown in the figure is for testing the electrical characteristics of a low current consuming electronic circuit such as a U-MOS type half-rod integrated circuit. More specifically, the test device 20 shown in the figure is designed primarily to test the direct current characteristics of an O-MOS type semiconductor integrated circuit with low current consumption. The test device 20 includes a test illumination Ei, a resistor R, a switching circuit 31, a timer circuit TMja, a pressure measuring means 22, a current measuring means 24, and the like. Test City, Ryo F, i generates a predetermined test tolerance pressure Vi. This test) Q Ryo E + is configured so that its output voltage can be variably controlled from the outside. That is, as shown in FIG. 4, the circuit is configured so that, in response to a control signal from the outside of the IC 1, in addition to the normal 0) test voltage Vi, a voltage vh that is significantly higher than that can also be output. The output vh or ■1 of this test power supply Ei traces the switching circuit S] and the resistor R2, is output to the test terminal '1'P, and is further output to the test connecting cable 3.
0, the electrical state of the circuit under test 10 is observed by the voltage measuring means 22 and the current measuring means 24 of the test apparatus 20. Here, the test power supply Ei As shown in Figure 4,
It is configured to temporarily output a high voltage vh at an initial stage when a voltage is output from there. After outputting a good voltage vh, the normal test voltage v
It is set to return to 1. The time it takes for the first high voltage vh to be output is determined by the time limit circuit TM.
Controlled by Relo. That is, when a high voltage Vh is output for the first time, the timer circuit TM detects this and starts counting a certain period of time dT. When the measurement of the certain period of time dT0) is completed, the completion state of the time measurement of the time limit circuit TM is inputted as a control signal to the test power source Ei. As a result, the test power supply E1 once outputs the high voltage vh for a certain period of time dT, and then returns to the state of outputting the normal low test voltage Vi. Then, in the above manner, the test voltage is adjusted to the circuit under test]
The test voltage is temporarily raised at the initial stage when the voltage is applied to 0 (as shown in FIG. 4, the charging of the capacitance Of parasitic to the connection cable 30 etc. After being returned to the test voltage Vi, the charging of the capacitance Of is almost completed and the state becomes ready for measurement immediately without waiting for the charging time of the capacitance Of.Thus, The test time is significantly shortened. In Figure 4, ■ shows the state of change in the test circuit voltage Vx applied to the circuit under test 10. In addition, Figure I shows the state of change in the test circuit voltage Vx applied to the circuit under test 10. circuit current I
The state of change of x is shown. The dotted line in the figure indicates high πT.
This shows a state in which the normal test voltage vi is output from the beginning without outputting the voltage Vh. As is clear from FIG. 4, the test device 20
Regardless of the storage capacity Of, it depends on the state in which it can be measured immediately. 5 and 6 show other embodiments of the test device according to the invention. The device 20 shown in the figure is basically the same as that of the embodiment described above. However, here is a reminder, the above time limit circuit T
A voltage detection means 26 is provided in place of M, thereby controlling the time at which the first high voltage Vh'b- appears. The voltage detection means 26 has two test terminals T of the test device 20σ.
Detect the voltage at P. (σ) When the detected voltage becomes equal to or higher than the constant voltage Vc, a detection output of the detection means 26 is given to the test power supply E1 as a control signal. As a result, the test voltage Ei is shifted from the initial high voltage vh to a state in which it outputs the normal test voltage Vi. The constant voltage Vc at which the detection means 26 operates is set, for example, to a voltage in the vicinity of the circuit voltage Vx in a steady state when a normal test voltage Vi is applied. In this embodiment, first the output "f" height (voltage vh
can be made sufficiently high. Therefore, the charging time for the capacitance Of parasitic on the cable 30 and the like can be shortened accordingly, and the test waiting time can be shortened. This is particularly effective when the circuit voltage Vx can be roughly predicted. FIG. 7 shows another embodiment of the test device according to the invention. The apparatus 20 shown in the figure is basically the same as the embodiment shown in FIGS. 5 and 6. Here, the test power supply ■
The voltage vh that is first output from the voltage source is controlled by a differentiating circuit 28. This differentiating circuit 28 has a test terminal '
Detect the voltage change dv/dt at 1゛P. Furthermore, the output voltage of the test power supply E+ is increased in proportion to the detected output, or in proportion to the square or cube thereof. As a result, the output of test) N 1:'J+ is greatly increased during the initial period when this signal is output to the test terminal 'I' P, which prevents charging of the capacitance af parasitic on the cable 30, etc. Speed up. On the other hand, it has a voltage detection means 26, and this detection means 2
6 is the test terminal T9VC of the test device 20'j)
Detect 1- on V. When the detected voltage exceeds the constant voltage Vc, the detected output of the detecting means 26 is given to the differentiating circuit 28 as a control signal. As a result, the differentiating circuit 28
stops operation 7, and stops increasing the output voltage of the test power supply Ei. At the same time, the detection output of the detection means 26 is inputted to the test power supply E+ as a control signal σ. As a result, the test power supply Ei once outputs a good voltage vh, and then outputs a normal low test voltage V1. As mentioned above, at 17, Tess l□! voltage is the circuit under test 10
If the voltage applied to the test is temporarily increased, the capacitance of
charges faster. Therefore, after returning to the normal test voltage Vi, the charging of the capacitance Of is almost completed, and the state is ready for measurement immediately without waiting for the charging time of the capacitance Of. becomes. As a result, the test waiting time is significantly reduced by -3n. [Effects] (1) By temporarily outputting a high voltage at the beginning of the test, it is possible to perform the test in a short time. (2+ Temporarily outputting a high voltage at the beginning of the test has the effect that measurement can be performed immediately after applying the test voltage. (3) Temporarily outputting a high voltage at the beginning of the test 4) As a result, it is possible to shorten the time required to apply a test voltage for measurement. Due to the above (1) to (3), a synergistic effect is achieved in that DC characteristics tests of low current consumption 9' nested circuits such as 0-MO8 semiconductor integrated circuits can be conducted efficiently. Although the invention made by the inventor has been specifically explained based on examples, it goes without saying that this invention is not limited to the above-mentioned examples, and can be modified in various ways without departing from the gist thereof. For example, the above-mentioned test power supply may have a plurality of power supplies with different output voltages. “Although we have explained the case where it is applied to test technology for low-current consumption semiconductor integrated circuits, which is a field of application that has become popular, it is not limited to this.For example, remote measurement of electronic circuits connected to communication lines etc. It can also be applied to technology, etc.At least it can be applied to conditions where a predetermined voltage is applied to the circuit under test to test the DC characteristics.In the above explanation, the test equipment was explained to Wang,
The present invention is not limited thereto, but can be applied to all methods that force the voltage of a certain node to a predetermined potential.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a test device developed by the present inventor seven years prior to this invention, Fig. 2 shows an example of the operation of the device shown in Fig. 1, and Fig. 3 is a timing chart of this test device. A circuit diagram showing one embodiment of the test device according to the invention, FIG. 4 is a timing chart showing an example of the operation of the device shown in FIG. 3, and FIG. 5 shows another embodiment of the test device according to the invention. 6 is a timing chart showing an example of the operation of the device shown in FIG. 5; FIG. 7 is a circuit diagram showing another embodiment of the test device according to the present invention. 10... Circuit under test, 20... Test device, 22
... Voltage measuring means, 24... Current measuring means, 26...
・Voltage detecting means, 28 ・Differentiating circuit, 30...Connection cable nope El...Test connection, Sl...Switching circuit, R...Resistor, ■1...Normal test IN pressure,
vh...Initial application type 1 voltage, VX ・Circuit'voltage, I
x...Circuit current, Of'...Cable parasitic capacitance. Fig. 1, 20 Fig. 2 Fig. 3, z. t,---,,j Figure 4, Figure 5, 7. ? θ , −−−−−−−−−−−−−” □ Figure 7 0

Claims (1)

[Claims] ] has a test power supply that generates a predetermined test voltage, and marks the test voltage from the test power supply on the circuit under test.
1. A test device for measuring the electrical characteristics of a circuit under test, wherein the test voltage is temporarily raised at an initial stage when the test voltage is applied to the circuit under test. 2. The test device according to claim 1, wherein the test voltage is set to be high for a certain period of time at the initial stage of testing. 3. At the initial stage when the test voltage described in F is applied to the circuit under test, the test voltage is raised (at the same time, a means for detecting the voltage applied to the circuit under test is provided, and a voltage of a certain level or higher is detected by the means for detecting the voltage). 3. The test device according to claim 1 or 2, wherein the test voltage is returned to the normal test voltage when the test voltage is exceeded. 4. A differentiating circuit for detecting a change state of the voltage applied to the circuit under test, and means for detecting the voltage applied to the circuit under test, and increasing the test voltage according to the output of the differentiating circuit. 10. Any one of claims 1 to 3, characterized in that the test voltage is returned to a normal test voltage when a voltage above a certain level is detected by the detection means. Test equipment as described in one.