JP2000206175A - Apparatus for measuring lsi current - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict the cost increase of LSIs by measuring a consumed current at a high speed without depending on a performance of an LSI tester. SOLUTION: A board 10 exclusive for measuring current is set to the LSI current-measuring apparatus. The current-measuring board 10 is constituted of a current detect resistor 12, a differential amplifier 14 and a window comparator 16. The window comparator 16 is constituted of an upper limit detect comparator 22, a lower limit detect comparator 24 and an OR circuit 26. Input/output terminals of the current-measuring board 10 comprise a current feed terminal 30, a terminal 36 where the current is to be measured, an upper limit input terminal 32, a lower limit input terminal 34 and a judgment result output terminal 38.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an LSI current measuring apparatus capable of measuring current consumption simply and at high speed and determining the current consumption.

[0002]

2. Description of the Related Art FIG. 4 shows a general configuration of an LSI measuring apparatus. The device under test is a DUT (Device Und
er Test) is placed on a board 48 and connected to the LS via a test board 46, a test head 44 and a cable 42.
It is measured by the I tester 40.

Conventionally, the current consumption of an LSI is measured using the current measurement function of the LSI tester 40, and the measurement time depends on the performance of the LSI tester 40. For example, there is an LSI tester in which a current value is converted into a voltage value inside the LSI tester 40 and then subjected to analog / digital conversion to make a determination based on an upper limit value or a lower limit value and a digital value. In this case, the measurement of the current consumption requires a very long time. Also, L
Since the SI tester 40 ensures the versatility of current measurement, it generally takes a long time to measure.

[0004]

The measurement of the current consumption is performed by using LS.
If left to the functions in the I tester, the measurement takes a long time, and the cost of the LSI increases. Furthermore, in recent years, I
A method called DDQ measurement has been applied. The IDDQ measurement is a method in which after a test pattern is executed, the state of the logic inside the LSI is set to a predetermined state, and current consumption is measured to find a defective portion of the logic inside the LSI. For this reason, the consumption current must be measured many times, and the cost of the LSI has increased significantly.

Accordingly, an object of the present invention is to measure current consumption at high speed and suppress an increase in cost of an LSI.

[0006]

In order to solve the above problem, an LSI current measuring apparatus according to the present invention comprises a current supply terminal, a current measurement terminal, an upper limit input terminal, a lower limit input terminal, and a judgment result output terminal. A resistor having one end connected to the current supply terminal and one end connected to the current-measured terminal, and a differential amplifier having both ends of the resistor connected to two input terminals; An output terminal of the amplifier is connected to one terminal of an input, and the upper limit input terminal is a first comparator connected to one terminal of a different input, and an output terminal of the differential amplifier is connected to one terminal of an input. A second comparator whose lower input terminal is connected to one terminal of a different input;
A logic circuit that combines the output of the first comparator and the output of the second comparator, the output of the logic circuit being provided with a current measurement board connected to the determination result output terminal. I do.

[0007]

Function and Effect Since the current measuring board in the LSI current measuring apparatus of the present invention has only a current supply terminal, a current measurement terminal, an upper limit input terminal, a lower limit input terminal and a judgment result output terminal, the test is performed. Easy to mount on board. In addition, since there are few components on the current measurement board, defective products can be determined at high speed, and the physical area of the current measurement board can be reduced.

Further, when the LSI current measuring apparatus of the present invention is used, since the current measuring function of the LSI tester is not used, the current can be measured simultaneously with the function check of the logic inside the LSI, and the total measuring time can be shortened. Can be achieved.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing an LSI current measuring device according to an embodiment of the present invention. The device under test is placed on the DUT board 48 and measured by the LSI tester 40 via the test board 46, the test head 44 and the cable 42. The current measurement board 10 is mounted on the test board 46.

FIG. 2 shows a current measuring board 1 according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a circuit configuration of a zero. The current measurement board 10 includes a current detection resistor 12, a differential amplifier 14, and a window comparator 16. Window comparator 16
Is the upper limit detection comparator 22, the lower limit detection comparator 2
4 and an OR circuit 26. Current measurement board 1
0 input / output terminals are the current supply terminal 30 and the current measured terminal 3
6, an upper limit input terminal 32, a lower limit input terminal 34, and a determination result output terminal 38.

FIG. 3 is a diagram for explaining the configuration of an LSI current measuring apparatus according to an embodiment of the present invention when measuring current consumption. The current supply terminal 30 is connected to the cable 4 from the LSI tester 40.
2. A constant power supply voltage is supplied via the test head 44 and the test board 46. D is a current measuring terminal 36
It is connected to the power supply terminal of the device under test via the UT board 48. The upper limit input terminal 32 and the lower limit input terminal 34
Voltages for setting the upper and lower limits are respectively input from the SI tester 40. The signal from the judgment result output terminal 38 is sent to the LSI tester 4 via the test head 44 and the cable 42.
Input to 0.

As shown in FIG. 2, the current detection resistor 12 is provided between the current supply terminal 30 and the current measurement terminal 36. One end of the current detection resistor 12 on the side of the current supply terminal 30 is connected to the non-inverting input terminal of the differential amplifier 14, and one end of the current detection resistor 12 on the side of the current measured terminal 36 is connected to the inverting input terminal of the differential amplifier 14. Have been. Differential amplifier 1
The output terminal of No. 4 is connected to the non-inverting input terminal of the upper limit detection comparator 22 and is connected to the inverting input terminal of the lower limit detection comparator 24. The upper limit input terminal 32 is connected to the inverted input terminal of the upper limit detection comparator 22, and the lower limit input terminal 34 is connected to the non-inverted input terminal of the lower limit detection comparator 24. The output terminal of the upper limit detection comparator 22 and the output terminal of the lower limit detection comparator 24 are OR circuits 2
6 input terminals. The output terminal of the OR circuit 26 is connected to the determination result output terminal 38.

When a current flows from the current measuring terminal 36, a voltage is generated across the current detecting resistor 12. This voltage is amplified by the differential amplifier 14 at a predetermined magnification. The upper limit detection comparator 22, the lower limit detection comparator 24, and the OR circuit 26 constitute a window comparator 16. When the output voltage of the differential amplifier 14 is higher than the input voltage of the upper limit input terminal 32, and when the output voltage of the differential amplifier 14 If the input voltage is lower than the input voltage of the lower limit input terminal 34, a high level is output to the determination result output terminal 38, and the LSI tester 40 determines that it is defective.

In the above embodiment, the current measuring board having the lower limit input terminal 34 and capable of determining the lower limit of the current consumption has been described. However, the current measuring board having no lower limit input terminal 34 and determining only the upper limit of the current consumption is described. Boards are also feasible.

[Brief description of the drawings]

FIG. 1 is a diagram showing an LSI current measuring device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a circuit configuration of a current measurement board according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration at the time of measuring current consumption of an LSI current measuring device according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating a general LSI measurement apparatus.

[Explanation of symbols]

 1: LSI measurement device 2: LSI current measurement device 10: current measurement board 12: current detection resistor 14: differential amplifier 16: window comparator 22: upper limit detection comparator 24: lower limit detection comparator 26: OR circuit 30: current supply terminal 32 : Upper limit input terminal 34: Lower limit input terminal 36: Current measured terminal 38: Judgment result output terminal 40: LSI tester 42: Cable 44: Test head 46: Test board 48: DUT board

Claims (1)

[Claims] 1. A terminal having only a current supply terminal, a current measurement terminal, an upper limit input terminal, a lower limit input terminal, and a judgment result output terminal, one end being connected to the current supply terminal and a different end being different from the current measurement terminal. A differential amplifier having both ends connected to two input terminals, an output terminal of the differential amplifier connected to one input terminal, and the upper limit input terminal having a different input terminal. A first comparator connected to a terminal, an output terminal of the differential amplifier connected to one terminal of an input,
A second comparator having the lower limit input terminal connected to one terminal of a different input, and a logic circuit combining an output of the first comparator and an output of the second comparator, wherein an output of the logic circuit is An LSI current measurement device including a current measurement board connected to the determination result output terminal.