JPS5896259A - Measuring method for supply current, etc. of semiconductor integrated circuit - Google Patents

Abstract

PURPOSE:To shorten a time required for measuring a current value, etc. by incorporating a discriminating means into a semiconductor integrated circuit. CONSTITUTION:Measurement is made in such a manner that, after an input signal is impressed from an input terminal 4 so as to determine the state of the inside, a contact 14 is opened and a voltage made to fall by an outside resistor 13 is compared with a reference voltage 12 (equivalent to the norm of a current) by a comparison circuit 15. The result of the comparison is latched on a latch circuit 17, and a latch output 11 is discriminated at a time point whereat all the measurements are ended, whereby it is made clear whether a supply current or a supply leakage current is within a norm or not. By this method, a time required for reading a value of a conventional ammeter can be shortened sharply. In addition, a current can be measured simultaneously when a function test is performed, and therefore, the measurement can be conducted without inputting any specific input signal for measurement of the current. Thus, the time can be shortened sharply also in this regard.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring power supply current, etc. of a semiconductor integrated circuit.

Conventionally, the method shown in FIG. 1 has been used to measure the power supply current or power supply leakage current of a semiconductor integrated circuit. In the figure, (1) is a semiconductor integrated circuit, (2) is a power supply terminal, (3) is a ground terminal, (4) is an input terminal, (6) is a current needle for measuring power supply current or power supply leakage current, ( 6)
is a power supply, and (7) is a pulse generator that generates an input signal.

Next, the measurement method will be explained.

When measuring the power supply current or power supply leakage current in an integrated circuit (1) with a large degree of integration, only a part of the circuit can be evaluated by measuring only one state. Any rjji measurement must be made by applying an input quantity to set the internal state, i.e. to set the desired internal state, a pulse generator (7) is used and the input terminal (4) Input the yoυ input signal. After that, stop the operation of the pulse generator (γ),
Measure the stain source current 1 or power source leak current using the current needle (6) K. continue.

To set the integrated circuit (1) in a state different from its initial state, different input signals are applied and measured in the same manner as described above. By repeating this process, we integrated 9 circuits (1)
The integrated circuit (1) is evaluated by measuring it in all states.

However, in the conventional measurement method described above, 1rj! In order to determine the value of i, it takes time to apply the input signal, time for the ammeter (6) to stabilize after stopping the application of the input signal, and time to measure the current. In the case of a large semiconductor integrated circuit (1), there is a drawback that it takes an enormous amount of time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for measuring power supply current, etc. of a semiconductor integrated circuit, which can reduce the time required to measure current values, etc. by incorporating a determination means into the semiconductor integrated circuit. It is said that

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is for explaining a method for measuring power supply current, etc. of a semiconductor integrated circuit according to the present invention, and the same parts as in FIG. In the same figure, (
8) is a terminal that provides a reference voltage to one input terminal of the comparator circuit, (9) is a strobe terminal that provides timing for current measurement, (to) is a reset terminal, and (b) is an output terminal that outputs the judgment result. , (b) is a power supply that provides a reference voltage, (to) is an external resistor that converts current to voltage, (2) is a contact such as a relay that is short-circuited except for the fixed time on the current side, and (b) is a circuit (1). ) is built in itself and constitutes the determination means (b) with a latch circuit which will be described later; and (b) is also a built-in number V gate F] which constitutes the latch circuit (b). The contact point (b) can also be made non-contact type by using a switching transistor or the like to increase the measurement speed.

Next, the operation will be explained.

As with the conventional method, in order to determine the internal state, the input voltage was applied to the input terminal (4), and then the voltage was lowered by the external resistor (b). The voltage is compared with a reference voltage Ql (corresponding to the current standard) by a comparator circuit (2). The result is latched into the latch circuit αη, and when all measurements are completed.

By determining the latch output (b), it can be determined whether the power supply current or power supply leater current is within the standard.

According to this method, the time it takes to read the value of a conventional ammeter can be significantly shortened. Since the current can be measured at the same time as the two-dimensional test, the measurement can be performed without inputting an input signal for current measurement, and in this respect as well, the time can be significantly reduced.

Note that the external resistor (b) may also be built into the semiconductor integrated circuit (1), and the determination means (to) may be constructed only by eliminating the latch circuit αη and replacing it with a comparison circuit. It is easy to judge the output from (2).

As described above, according to the present invention, it is advantageous to incorporate a determination means that does not increase the chip area in the semiconductor integrated circuit itself, and even in a highly integrated circuit, the power supply current, etc. This has the effect of allowing quick measurements.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional method for measuring power supply current, etc. of a semiconductor integrated circuit, and FIG. 2 is an explanatory diagram of a method of measuring power supply current, etc. of a semiconductor integrated circuit according to the present invention. (1) - Semiconductor integrated circuit, (2) - Power supply terminal, (3
)...Ground terminal, (4)--Input terminal, (7)--Pulse generator, (8)...Reference voltage application terminal, (to)-
...external resistor, (b) - comparison circuit, (b) ... latch circuit, (e) ... determination means. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent: Ge Shuxin (1 other person)

Claims (1)

[Claims] (1) Out of the determination means to which a reference voltage is applied and the external resistor connected to the power supply terminal or the ground terminal of the semiconductor integrated circuit, at least the determination means is built into the semiconductor integrated circuit, and the input terminal of the semiconductor integrated circuit The voltage drop across the external resistor after applying an input signal to the external resistor is compared with the reference voltage of the determining means, and it is determined from the output from the determining means whether or not the current value is within the standard. A method for measuring power supply current, etc. of semiconductor integrated circuits.