JPH1152007A - Dc characteristic measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a device by making an output voltage one input to a DC characteristic measuring device, making a value of resistance the other input, and adding a diving circuit for performing current setting by the output of the DC characteristic measuring device. SOLUTION: Sense output 9 and force output 10 are connected to terminals to which the resistance of an IC to be measured is desired to be connected. When resistance setting is commanded by a program, the second relay 11 is brought to fall to the side of (f) and the third relay 12 is brought to fall to the side of (f). The second D/A converter 2 output a value of resistance to be set, the value of resistance is inputted to one input terminal of a dividing circuit 13, and a sense output voltage is inputted to the other input terminal. As a result, the dividing circuit 13 outputs a desired current value to be set. A current which a final amplifier 5 is to pass by a loop 2 is controlled by the desired current value, and a current which the final amplifier 5 passes finally becomes an output voltage/a value of resistance to set. Therefore, the D/C characteristic measuring device becomes a resistor with a value of resistance to set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC characteristic measuring instrument,
Particularly, the present invention relates to a DC characteristic measuring device mounted on a tester used for IC inspection.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional DC characteristic measuring device mounted on a tester used for IC inspection has a first D / A converter 1 for converting a digital voltage value into an analog value. A second D / A converter 2 for converting a digital current value to an analog value, a summing circuit 3 for selecting whether to perform voltage setting or current setting, and feedback of a sense output for voltage setting. Buffer 4, a final amplifier 5 that amplifies the output of the summing circuit 3 and supplies a voltage and current to the output, a current detection circuit 6 that feeds back the output current for current setting, and measures the voltage output or the current output. Relay 7 for switching whether or not to measure the measured value, and A for converting the measured value to a digital signal.
/ D converter 8. Summing circuit 3 and final amplifier 5
Form a differential amplifier.

Next, the operation of a conventional DC characteristic measuring device will be described.

First, voltage application and current measurement will be described.

When a command for voltage application and current measurement is described in a program, a voltage value to be applied to the output of the first DA 1 is output, and this value and the sense output 9 are transferred to the buffer 4 via a summing circuit. The feedback is applied in LOOP1 so that the final amplifier 5 supplies the output voltage so that the value fed back in the same manner as above, and the voltage value described in the instruction is output.
(At this time, the sense output 9 and the force output 10 are short-circuited at the supply destination.) In the output current measurement, the first relay 7 falls to the b side, and the output of the current detection circuit 6 is the A / D converter 8 , And A /
The D converter 8 converts this value into a digital value, and the tester reads this digital value and the measurement is completed.

Next, current application and voltage measurement will be described.

When a command for current application / voltage measurement is described in the program, a current value to be applied to the output of the second D / A converter 2 is output, and this value and the current detection are output via a summing circuit. Feedback is applied in LOOP2 so that the final amplifier 5 supplies the output current so that the output of the circuit 6 becomes the same, and the current value described in the instruction is output.

In the output voltage measurement, when the first relay 7
Side, and the output voltage is supplied to the A / D converter 8 through the buffer 4.
The A / D converter 8 converts this value into a digital value, and the tester reads this digital value and the measurement is completed.

Recently, a tester used for IC inspection generally has this DC characteristic measuring device at each pin.

[0010]

By the way, the measurement of the output characteristic of a circuit by a DC characteristic measuring instrument is often performed under the condition that an external load is connected. This is because the circuit is usually used with a load connected, and accordingly, the output characteristics with the load connected are adjusted at the design stage, checked at the manufacturing stage, and the data book. Because it is necessary to put it on

However, in this conventional DC characteristic measuring device, as shown in FIG.
Only the current can be set by OOP2, and the DC characteristic measuring device cannot be used as a resistor having an arbitrary value. In addition, it is not possible to measure characteristics in a state where an arbitrary resistor is virtually connected.

However, the following cases are considered possible.

If it is intended to connect a resistor by a DC characteristic measuring device to the output terminal of the IC to be measured and the current does not change the voltage of the output terminal, first, the output voltage of the DC characteristic measuring device is changed by the DC characteristic measuring device. Measure, divide the voltage by the resistance value to be set between the output and the ground, calculate the current value to be set, then set the current value with a DC characteristic measuring instrument and connect it to set the resistance Becomes possible.

However, even in this case, two operations of voltage measurement and current setting are required.

For this reason, it is usually necessary to measure the characteristics after externally connecting a necessary resistor to the test board.

Accordingly, the present invention provides a DC current characteristic in a state where a load resistor is connected without connecting a load resistor.
An object of the present invention is to provide a DC characteristic measuring device capable of measuring a voltage characteristic.

[0017]

A DC characteristic measuring instrument according to the present invention comprises a voltage detecting means for detecting a voltage at one terminal of an external circuit, and a current detecting means for detecting a current flowing out or flowing into one terminal of the external circuit. Means, the difference between the measured value of the voltage detecting means and a predetermined voltage value or the difference between the measured value of the current detecting means and a predetermined current value, and outputs the output of the external circuit through the current detecting means. In a DC characteristic measuring device including a differential amplifier to be supplied to one terminal and measuring means for measuring a voltage detected by the voltage detecting means or a voltage detected by the current detecting means, the voltage detecting means further detects A division circuit that divides a voltage by a set resistance and outputs a quotient as a set current; and a switch that switches an input of the differential amplifier between the set current and a current detected by the current detection means. The current given by the voltage / setting resistance with respect to the ground of the one terminal of the external circuit is supplied or drawn into one terminal of the external circuit, and the voltage and the current of one terminal of the external circuit at this time are measured. The feature is that it is possible.

Further, the DC characteristic measuring device according to the present invention comprises a first voltage detecting means for detecting a voltage at one terminal of an external circuit, and a first voltage detecting means for detecting a current flowing out or flowing into one terminal of the external circuit. A current detecting means, amplifies a difference between a measured value of the voltage detecting means and a predetermined voltage value, or a difference between a measured value of the current detecting means and a predetermined current value, and outputs the output to the external device through the current detecting means; A DC characteristic measuring device comprising: a first differential amplifier supplied to one terminal of a circuit; and a measuring means for measuring a voltage detected by the voltage detecting means or a voltage detected by the current detecting means. A second voltage detecting means for detecting a voltage of the other one terminal, a second current detecting means for detecting a current flowing out or flowing into the other one terminal, and a detecting means of the first voltage detecting means. Voltage and said second voltage A dividing circuit that divides the difference between the voltage detected by the output means and the set resistance to output a quotient as a set current; and amplifies the difference between the set current and the current detected by the second current detecting means. A second differential amplifier for supplying an output to the other terminal of the external circuit through the second current detecting means, and an input of the first differential amplifier to the setting current and the current detecting means. A switch for switching to a current to be detected, and a current given by (voltage of one terminal of the external circuit−voltage of another terminal of the external terminal) / setting resistance is supplied to one terminal of the external circuit, or The second differential amplifier draws the current given by the above equation into the first differential amplifier.
Of the external circuit at this time.
It is characterized in that it is possible to measure the voltage and current of the terminal.

The constant resistance circuit according to the present invention has one of the external circuits.
A division circuit that divides a voltage of the terminal with respect to ground by a set resistance to output a quotient as a set current, and current control means that causes the set current to flow to one terminal of the external circuit; And a current given by a voltage / setting resistance with respect to the ground of one terminal of the external circuit.

Further, the constant resistance circuit according to the present invention includes a division circuit for dividing a voltage between two terminals of an external circuit by a set resistance and outputting a quotient as a set current, and a circuit for dividing the set current into one of the external circuits. And a second current control means for flowing the set current to the other terminal of the external circuit in a complementary manner with the one terminal, wherein two terminals of the external circuit are provided. In addition, a current given by a voltage / setting resistance between two terminals of an external circuit is complementarily supplied or drawn.

Furthermore, a constant resistance circuit according to the present invention is characterized in that in the above constant resistance circuit, the current control means includes a current detection circuit and a differential amplifier.

A DC characteristic measuring device according to the present invention includes the above-described constant resistance circuit.

[0023]

Embodiments of the present invention will now be described with reference to the drawings.

[Embodiment 1] FIG. 1 shows Embodiment 1 of the present invention.
3 is a block diagram of the DC characteristic measuring device of FIG.

However, the sense output 9 and the force output 1
0 is connected to the terminal to which the resistance of the IC to be measured is to be connected.

When a resistance setting command is described in the program, the second relay 11 is set to the C side, and the third relay 12 is set to f
Side, the resistance value to be set to the output of the second D / A converter 2 is output, and the dividing circuit 13
The resistance value is input to one input terminal, the sense output voltage is input to the other input terminal via the buffer 4, and the output of the division circuit 3 is the resistance value to be set as the sense output voltage. The current value to be set calculated from is output,
Feedback is applied by LOOP2 via the summing circuit so that the final amplifier 5 supplies an output current so that this value and the output of the current detection circuit 6 become the same, and a current value corresponding to the resistance value to be set is output. .

When the output voltage is changed by the output current, the output voltage of the LOOP 3
Feedback is applied, and the resistance value finally set is set.

That is, the measured output I
The output voltage of C is measured. From the value of the output voltage and the value of the resistance to be set, the dividing circuit 13 obtains a target current calculated by the output voltage / the resistance to be set. Then loop 2
As a result, the current to be passed by the final amplifier is controlled to this target current, and eventually, the current to be passed by the final amplifier becomes output voltage / resistance to be set. Therefore, the DC characteristic measuring device is a resistor having a resistance value to be set.

Next, the fluctuation will be described. For example, consider the case where the power supply voltage is positive and the DC characteristic measuring device draws current. When the amount of current drawn by the final amplifier 5 increases and the output voltage decreases, this is detected by the sense output 9, so that the target current which is the output of the division circuit 13 calculated by the output voltage / the resistance value to be set. Decreases. Then, the loop 2 acts in a direction in which the amount of current drawn by the final amplifier 5 decreases, and eventually, the amount of current drawn by the final amplifier 5 returns to the original value, and the output voltage also returns to the original value. Therefore, the amount of current drawn by the final amplifier 5 is a value uniquely determined by the resistance value to be set and the output voltage of the IC to be measured.

The output voltage value and the output current value when the current driven by the final amplifier is determined in this way can be measured by switching the first relay. That is, when the first relay is connected to the a side, the output voltage can be measured, and when the first relay is connected to the b side, the output current can be measured.

The summing circuit 3 and the final amplifier 5 form a differential amplifier.

The case where the resistance is set between the output of the GND and the DC characteristic measuring device has been described.

[Embodiment 2] FIG. 2 shows Embodiment 2 of the present invention.
3 is a block diagram of the DC characteristic measuring device of FIG.

In order to set a resistance between the terminal to which the sense output 9 and the force output 10 of this DC characteristic measuring device of the IC to be measured are connected and another terminal of the IC to be measured, one input is provided. The output of the differential circuit 14 in which a matrix line 16 is connected to the output of the buffer 4 and the other input via a fourth relay 15 is connected to one input of a division circuit 13. The output of the division circuit 13 receives the output of the division circuit 13 and the output of the current detection circuit 18 and outputs the output via the current detection circuit 18 to a force output terminal 19 (reference numeral 1).
9) is added to the differential amplifier 17 to be supplied. The force output 19 (reference numeral 19) is short-circuited on the side of the IC to be measured.

In the program, this force output-GND
When a command for setting the resistance between the force output and the matrix line is described, not between the relays, the second relay 11 is on the C side, the third relay 12 is on the f side, and the fourth relay 15 is on.
Is programmed to fall to the g side, and if the other terminal is programmed to be connected to the g side of the fourth relay 15 via the matrix line 16, the differential circuit 14
Since the differential voltage between the terminals whose resistances are to be set is output to the output of, the current obtained by the differential voltage / set resistance calculated by the division circuit flows through the force output 10, and the force output 2 (sign 19), the same amount of current flows in the opposite direction to the force output 10. Therefore, a resistance value to be set is set between terminals to be set. When the first relay 7 is tilted to the a side, the difference voltage value between the terminals whose resistance is to be set can be measured, and when the first relay 7 is tilted to the b side, the current value between the terminals can be measured. Further, the force output and the G
If it is desired to set the resistance between ND, the fourth relay 15 may be tilted to the h side.

The summing circuit 3 and the final amplifier 5 form a differential amplifier.

[0037]

As described above, according to the present invention, the output voltage is set to one input, the resistance value to be set is set to the other input, and the current is set by the output in the conventional DC characteristic measuring instrument. Is added, the DC characteristic measuring device itself can be set as a resistor. Furthermore, the output current and the output voltage can be measured with the same DC characteristic measuring device while the DC characteristic measuring device itself is set as a resistor.

[0038] Therefore, in a per-pin tester equipped with these DC characteristic measuring instruments, an external resistor on the test board is not required, and the DC characteristic measuring device of the IC is simplified.
The trouble of the measurement is eliminated, and the measurement time can be reduced. Further, it is not necessary to provide a space for an external resistor on the substrate on which the IC is mounted.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of a DC characteristic measuring device according to a first embodiment of the present invention.

FIG. 2 is a circuit block diagram of a DC characteristic measuring device according to a second embodiment of the present invention.

FIG. 3 is a circuit block diagram of a DC characteristic measuring device according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st D / A converter 2 2nd D / A converter 3 Summing circuit 4 Buffer 5 Final amplifier 6, 18 Current detection circuit 7 1st relay 8 A / D converter 9 Sense output 10 Force output 11 2nd relay 12 3rd relay 13 Division circuit 14 Differential circuit 15 4th relay 16 Matrix line 17 Differential amplifier 19 Force output 2

Claims (6)

[Claims] 1. A voltage detecting means for detecting a voltage at one terminal of an external circuit, a current detecting means for detecting a current flowing out or flowing into one terminal of the external circuit; A differential amplifier for amplifying a difference between a voltage value or a difference between a measured value of the current detection means and a predetermined current value, and supplying an output to one terminal of the external circuit through the current detection means; A DC characteristic measuring device comprising: a voltage detected by the means or a measuring means for measuring a voltage detected by the current detecting means, further comprising: dividing a voltage detected by the voltage detecting means by a setting resistor to divide a quotient by a set current. And a switch for switching the input of the differential amplifier between the set current and the current detected by the current detecting means. One terminal of the external circuit has one terminal of the external circuit. Pouring a current given by the voltage / setting resistance to land, or pull, DC characteristic measuring apparatus according to claim that it is possible to measure the voltage and current of the first terminal of the external circuit at this time. 2. A first circuit for detecting a voltage of one terminal of an external circuit.
Voltage detecting means, first current detecting means for detecting a current flowing out or flowing into one terminal of the external circuit, a difference between a measured value of the voltage detecting means and a predetermined voltage value, or the current detecting means The difference between the measured value of the external circuit and the predetermined current value is amplified, and the output is output to the external circuit through the current detecting means.
A DC characteristic measuring device comprising: a first differential amplifier to be supplied to a terminal; and measuring means for measuring a voltage detected by the voltage detecting means or a voltage detected by the current detecting means. A second voltage detecting means for detecting a voltage of one terminal; and a second voltage detecting means for detecting a current flowing out or flowing into the other one terminal.
Current detection means, and the difference between the voltage detected by the first voltage detection means and the voltage detected by the second voltage detection means is divided by a set resistance,
A division circuit that outputs a quotient as a set current; and amplifies a difference between the set current and the current detected by the second current detection means, and outputs an output through the second current detection means to another of the external circuit. A second differential amplifier to be supplied to one terminal; and a switch for switching an input of the first differential amplifier between the set current and a current detected by the current detecting means. The current given by (the voltage of one terminal of the external circuit−the voltage of the other one terminal of the external terminal) / setting resistance is supplied or drawn into the terminal. The second differential amplifier outputs the current given by the above equation. Is output complementarily to the first differential amplifier, and the voltage and current at one terminal of the external circuit at this time can be measured. 3. A dividing circuit for dividing a voltage with respect to the ground of one terminal of the external circuit by a set resistance and outputting a quotient as a set current, and a current control means for flowing the set current to one terminal of the external circuit. A constant resistance circuit, wherein a current given by a voltage / setting resistance with respect to the ground of one terminal of the external circuit is supplied or drawn into one terminal of the external circuit. 4. A dividing circuit for dividing a voltage between two terminals of an external circuit by a set resistor and outputting a quotient as a set current, and a first current flowing the set current to one terminal of the external circuit. Control means, and second current control means for allowing the set current to flow to the other terminal of the external circuit complementarily to the one terminal, wherein two terminals of the external circuit are connected between two terminals of the external circuit. A constant resistance circuit characterized by complementarily flowing or drawing in a current given by a voltage / setting resistor. 5. The current control means comprises: a current detection circuit;
5. A differential amplifier comprising: a differential amplifier;
The constant resistance circuit according to the above. 6. A DC characteristic measuring device comprising the constant resistance circuit according to claim 3. Description: