JPH0933605A - Current measuring device for ic tester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a current measuring device, for an IC tester, which can be miniaturized and whose electric power can be lowered. SOLUTION: A prescribed voltage is supplied to a DUT by a device power- supply unit 11 which is provided with a voltage-application and current- measuring function and with a current-limiting function, and output short-circuit currents of several pins at the DUT are measured. A control switch K16 for testing of an output short-circuit current is installed at an input/output DC testing unit 31 so as to be controlled. When a switch K10 and the switch K16 are turned off and the prescribed voltage is applied to the DUT, consumption currents α at the inside of the DUT other than an output short-circuit current I11 are measured by the device power-supply unit 11. When the switch K10 is turned off and the switch K16 is turned on, the device power-supply unit 11 indicates the total output short-circuit current I13. The output short-circuit current I11=I13-α is found. By a circuit configuration in which the total output short-circuit current I13 is not made to flow to the whole circuit for the output DC testing unit 31, a current measuring device can be miniaturized, and its electric power can be lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current measuring device for an IC tester, which is a direct current test unit for conducting an input / output direct current characteristic test of a semiconductor under test (hereinafter referred to as DUT).

[0002]

2. Description of the Related Art An IC tester is equipped with a DC test unit for carrying out a DC test of the input and output of a DUT. However, in order to protect the DUT and connected peripheral circuits, a general input / output DC characteristic test is performed. The output short circuit current measurement requires a relatively large current limit and current measurement circuit. In order to measure the output short circuit current of the DUT, the DC test unit for input / output test must be equipped with a circuit capable of withstanding the short circuit current.
It was an obstacle to miniaturization and low power consumption.

A basic configuration diagram of the output short circuit current test of the DUT is shown in FIG. A voltage Vcc is applied to the collector of the transistor Tr1 of the circuit to perform an output short circuit current test of the DUT.
An output short-circuit current IH flowing with the collector side of the transistor Tr2 grounded to test the current protection ability of the current limiting element 8 incorporated between the emitter of the transistor Tr1 and the collector of the transistor Tr2.
It is tested whether the current limiting element 8 is activated and the protection circuit is activated by flowing A. Each transistor Tr1 in case of short circuit test,
The power consumption of Tr2 is PH = Vce in the transistor Tr1.
1 × IH and transistor Tr2 PL = Vce2 × IL
Becomes

FIG. 4 shows a block diagram of a DC test unit for an input / output test for measuring an output short-circuit current of an IC tester according to a conventional technique. There are several pins in one DUT that require output short-circuit current measurement. One pin will be described. When the output short circuit current test of the DUT is performed, a specified voltage is applied to the DUT from the device power supply unit 10 having a voltage applied current measuring function and a current limiting function,
The output current I1 of the UT is used as an interface to the input / output pins of the DUT.
Output current I2 is passed through the input / output DC test unit 30
The input / output DC test unit 30 having a voltage applied current measuring function and a current limiting function, which is input to the output of the DUT, has a circuit that can directly short-circuit the test whether the protection circuit for current control of the DUT operates normally. Measure the short circuit current.

In the DUT normal current input / output test, the switch K0 is turned on, the switch K5 is turned off, and the resistor R
Test in the current range of 3 and R4. In the output short-circuit current test, the switch K0 is turned on, the switch K4 is turned off, the switch K5 is turned on, and the test is performed in the current range of the resistor R5.

Since the normal current of the DUT is about 8 mA and about 24 mA / 48 mA for buffer, it is 60
A current capacity of about mA may be sufficient, but in a short circuit that tests whether the protection circuit for current control action of the DUT operates normally, the output short circuit current of the DUT requires about 150 mA, and the device power supply unit 10 also becomes large. It was necessary to increase the size of the device in order to make the circuit configuration capable of handling about 150 mA including the switching mechanism of the input / output DC test unit 30.

The resistance R3 of the input / output DC test unit 30,
R4 and R5 detect and limit the current, a current of several microamperes flows through the resistor R3, and a short circuit current of several hundred milliamperes flows through the resistor R5. Thus, in order to measure the output short circuit current of the DUT, the input / output DC test unit 30
Since it is necessary to allow a large current to flow through the amplifier A1 and the resistor R5, the input / output DC test unit 30 becomes large. It is difficult for the large-sized I / O DC test unit 30 to accommodate all hundreds of DUT pins. The IC tester has a per-pin system that corresponds to each pin of the DUT and a shared pin that switches the conditions required for the pins of the DUT.
There is a resource method, but even if the shared resource method is used to switch to the required pins, several tens of IC testers are required.

[0008]

SUMMARY OF THE INVENTION As described above,
The DC test unit for the input / output test is provided with a large current circuit only for measuring the output short-circuit current, which hinders the downsizing and power reduction of the IC tester. Therefore, the problem to be solved by the present invention is that the output short circuit test is controlled by the input / output direct current test unit or the pin electronics section,
The current measurement of the output short-circuit test is performed by the device power supply unit, which aims at downsizing and low power consumption of the input / output DC test unit.

[0009]

In order to achieve the above object, control of an output short circuit test performed by a current measuring device of an IC tester of the present invention is performed by an input / output DC test unit or a pin electronics section, and an output short circuit test is performed. The current was measured by the device power supply unit. The output short-circuit test is controlled by the input / output DC test unit or the pin electronics section by using the means for measuring the voltage supply and current of the device power supply unit that has the voltage applied current measurement function and the current limiting function, and the total output short circuit of the DUT is performed. Current, current consumption, and normal current are measured by the device power supply unit, and the output short-circuit current is calculated.

Since the output short circuit test switch is provided at the entrance of the input / output DC test unit into which the total output short circuit current of the DUT flows through the pin electronics section, the circuit configuration for controlling the output short circuit test is adopted. A large current only flows through the control switch, and a large current does not flow in the entire circuit of the input / output DC test unit. Therefore, the current capacity of the circuit has only to meet the design standard of the normal current.

In addition to controlling the output short-circuit test, a switch for output short-circuit test is provided in the pin electronics section to have a circuit structure for controlling the output short-circuit test. Therefore, the input / output DC test unit does not control the output short-circuit test. Since the circuit configuration is such that the output short-circuit current does not flow into the input / output DC test unit, the current capacity has only to meet the design standard for normal current.

[0012]

[Function] Since the output short circuit test switch is provided at the entrance of the input / output DC test unit into which the total output short circuit current of the DUT flows through the pin electronics section, a large current such as the total output short circuit current flows through the control switch. However, since a large current does not flow through the entire circuit, the current capacity of the circuit only needs to meet the design criteria for normal current, which enables downsizing and low power consumption.

As another embodiment, when the output short circuit test is controlled by the pin electronics section, it is provided with a switch for output short circuit test in the pin electronics section to control the output short circuit test. Since the current does not flow, the current capacity of the circuit only has to satisfy the design standard for the normal current, which enables downsizing and low power consumption.

[0014]

EXAMPLES Examples will be described with reference to the drawings.
FIG. 1 shows a block diagram of a current measuring device of an IC tester. There are several pins in one DUT that require output short-circuit current measurement. One pin will be described. The device power supply unit 11 having a voltage applied current measuring function and a current limiting function applies a specified voltage to the DUT. For the normal current test of the device power supply unit 11, the switch K8 of the pin electronics section 21 is turned on, the switch K10 of the input / output direct current test unit 31 is turned on, and the switch K1.
Turn off 6 and test in the current range of resistors R13 and R14. The current in the DUT output short-circuit current test is expressed by the following formula. If the output short-circuit current is I11 and the consumption current inside the DUT other than I11 is α, the total output short-circuit current I
13 = I11 + α. In the output short-circuit current test, the switch K8 of the pin electronics section 21 is turned on, the switch K10 of the input / output DC test unit 31 is turned off, and the current consumption inside the DUT that flows when the switch K16 is off is α. When the switch K10 is turned off and the switch K16 is turned on, the current of the device power supply unit 11 shows the total output short-circuit current I13 and the output short-circuit current I11.
= I13−α.

The input / output DC test unit 31 having a circuit configuration in which the total output short-circuit current I13 does not flow in the entire circuit is a DUT.
Since it became the current capacity of normal operation of, the input / output DC test unit 3 with the voltage applied current measurement function and the current limit function
1 made it possible to reduce the size and power consumption. A DA converter 51 that creates a reference voltage for voltage application, a resistor R11 that is a constant voltage generation circuit using operational amplification, and an amplifier A12
And resistance R12, and AD that measures the current-voltage converted value
-The converter 61 and the current limiting circuit 71 are connected to the amplifier A11.
Connected to the switch A, the current supply capacity of the amplifier A11 is required by the resistor R4, for example, up to about 60 mA.
10 and the amplifier A13 that performs voltage conversion are also provided with components having the same current capacity. In the input / output DC test unit 31, only the switch K6 for controlling the output short-circuit current test is, for example, 20
Provided with parts that can withstand about 0 mA. The pin electronics section 21 is used as an interface for the input and output pins of the DUT.

A block diagram of the output short circuit current measurement of the IC tester of another embodiment for controlling the output short circuit test is shown in FIG. There are several pins in one DUT that require output short-circuit current measurement. One pin will be described. The pin electronics section 22 is provided with an output short circuit test switch K26 for controlling the output short circuit test to control the output short circuit test. As a result, the total output short-circuit current I130 does not flow in the input / output DC test unit 32. Since the input / output DC test unit 32 does not control the output short-circuit test, FIG.
Since the resistor R5 and the switches K5 and K6 which are included in the input / output DC test units 30 and 31 are unnecessary and have been removed from the circuit configuration, the current capacity of the circuit may satisfy the design standard of the normal current. 32 is smaller,
Low power consumption is possible.

The device power supply unit 12 having a voltage applied current measuring function and a current limiting function applies a specified voltage to the DUT. For the normal current test of the device power supply unit 12, the switch K21 of the pin electronics section 22 is turned on and the switch K100 of the input / output DC test unit 32.
Is turned on, and the test is conducted in the current range of the resistors R13 and R14. The current in the DUT output short-circuit current test is expressed by the following formula. When the output short-circuit current is I110 and the consumption current inside the DUT other than the output short-circuit current I110 is γ, the total output short-circuit current I130 = I110 + γ. The current inside the DUT flowing through the device power supply unit 12 when the switches K21 and K26 of the pin electronics section 22 are off is the consumption current γ. Output short circuit current test is DUT
When the switch K21 of the pin electronics section 22 is turned off and the output short-circuit test switch K26 is turned on, the output short-circuit current I110 changes to K26.
And the current of the device power supply unit 12 indicates the total output short-circuit current I130, the output short-circuit current I110 =
It is calculated by I130-γ.

[0018]

Since the present invention is configured as described above, it has the following effects. I
By measuring the output short-circuit current test of the current measuring device of the C tester with the device power unit, the total output short-circuit current does not flow in the circuit of the input / output DC test unit. Even the current measuring device of the per-pin type IC tester corresponding to each pin of the DUT, which can be downsized and reduced in power consumption, can be downsized and reduced in power consumption. The overall size can be reduced and the power consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a current measuring device of an IC tester according to an embodiment of the present invention.

FIG. 2 is a block diagram of a current measuring device of an IC tester according to a modified embodiment of the present invention.

FIG. 3 is a basic configuration diagram of an output short-circuit current test of a DUT according to a conventional technique.

FIG. 4 is a block diagram of a current measuring device of an IC tester according to a conventional technique.

[Explanation of symbols]

 A1, A11, A12, A13, A111 Amplifier A122, A133 Amplifier I1, I2 Output current K4, K5, K6, K10, K14, K16 Switch K21, K26, K100, K144 Switch I11, I110 Output short-circuit current I13, I130 Total output Short-circuit current R3, R4, R5, R11, R12, R13 resistance R14, R111, R122, R133 resistance R144 resistance Tr1, Tr2 transistor α, γ current consumption β, δ normal current 8 current limiting element 10, 11, 12 device power supply unit 20, 21, 22 Pin electronics section 30, 31, 32 Input / output DC test unit 51, 511 DA converter 61, 611 AD converter 71, 711 Current limiting circuit

Claims (4)

[Claims] 1. A device power supply unit (11) having a voltage applied current measuring function and a current limiting function, a pin electronics section (21) used as an interface for input / output pins of a DUT, and a unit for performing a normal current test is a DA. An amplifier (A11) including a converter (51) and a resistor (R11), an amplifier (A12) and a resistor (R12), an AD converter (61) and a current limiting circuit (71).
A resistor (R13) and a resistor (R14) connected to the output side of the amplifier (A11) and a switch (K1).
In the current measuring device of the IC tester having the input / output DC test unit (31) provided by connecting 4) to the amplifier (A13) for voltage conversion, the normal input / output to the input / output DC test unit (31) A current measuring device for an IC tester, comprising a switch (K10) for performing a current test and a switch (K16) for controlling an output short circuit test, and having the above configuration. 2. The component according to claim 1, wherein the DUT to which a specified voltage is applied is a DUT other than the total output short-circuit current (I13) and the output short-circuit current (I11) by the input / output DC test unit (31). Current consumption (α)
And the other normal current (β) are controlled to control the total output short-circuit current (I13) and the output short-circuit current (I11).
Other consumption currents (α) flowing in the DUT and other normal currents (β) are measured by the device power supply unit (11), and output short-circuit current (I11) = total output short-circuit current (I13) −
A current measuring device for an IC tester, comprising the above-mentioned configuration, which is calculated from current consumption (α). 3. A device power supply unit (12) having a voltage applied current measuring function and a current limiting function, and a unit for performing a normal current test are a DA converter (511) and a resistor (R).
111), an amplifier (A122) and a resistor (R122)
And AD converter (611) and current limiting circuit (71
1) is connected to the amplifier (A111), and the resistor (R133) and the resistor (R144) and the switch (K144) connected to the output side of the amplifier (A111) are connected to the amplifier (A133) for voltage conversion. In a current measuring device for an IC tester having an input / output direct current test unit (32) connected thereto, a pin electronics section (22) is provided with a switch (K26) for controlling an output short-circuit current test, and the above configuration is provided. A current measuring device for an IC tester, comprising: 4. The component according to claim 3, wherein the DUT to which a specified voltage is applied is a DUT other than the total output short-circuit current (I130) and the output short-circuit current (I110) by the input / output DC test unit (32). The total output short-circuit current (I130) and the output short-circuit current (I11) are controlled by controlling the consumption current (γ) flowing in the
0), the consumption current (γ) flowing through the DUT and the other normal current (δ) are measured by the device power supply unit (12), and the output short-circuit current (I110) = total output short-circuit current (I13)
0) -A current measuring device for an IC tester, which has the above-mentioned configuration, which is calculated from the current consumption (γ).