JP3180435B2 - LCD drive driver IC tester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal driver I
ICs to be tested with reference voltage, especially for C test equipment
The difference voltage between the output terminal voltage and the output terminal voltage can be detected with high accuracy, and the pass / fail judgment can be easily performed.
Further, the present invention relates to a liquid crystal drive driver IC test apparatus having a very short test time from the start of the test to the end of the test.

[0002]

2. Description of the Related Art A conventional example of a liquid crystal drive driver IC test apparatus will be described with reference to FIG. LCD driver IC1 is designed to output a relatively high pressure of the four voltage recovery several example voltage V ₁ ~V _4, the number of the output terminal T _OUT is up to 160 terminals or more of a number 80 to . Output terminal T
The number of _OUT tends to increase in the future.

Therefore, as shown in FIG. 1, a DC parametric test apparatus has conventionally been used for testing the liquid crystal drive driver IC1. Although detailed explanation is omitted,
This DC parametric test apparatus is configured by employing a current generation and voltage measurement device and a voltage generation and current measurement device. In Figure 1, a relatively test the selection of high test voltage V ₁ ~V ₄ voltage switch S _V1 ~ inputted
Carried out by S _V4, the output voltage V _{OUT 1} is a result voltages V ₁ which is selected is supplied to the liquid crystal driver IC1 to the first first through the test voltage switch S _V1 is output by the output voltage control CLK Terminal T _OUT1 to output terminal T
It is configured to appear sequentially at _OUT160 . Output terminal T
_OUT1 to output terminal T The output voltage V _OUT1 appearing sequentially at _OUT160
Are sequentially supplied to the DC level measuring device 50 via the output voltage changeover switches S _{T1 to} S _T160 to determine the result. Here, output voltage changeover switches S _{T1 to} S _T1
It is assumed that _{T160 is} also controlled in synchronization with the output voltage control CLK. Next, the selected voltage V ₂ is applied to the liquid crystal driving driver I.
C1 and also the resulting output voltage V
_OUT2 is sequentially at the output terminal T _{OUT 1} ~ output terminal T _{OUT 160,} a determination of the output changeover switch S _T1 to S _{T 160} is fed sequentially to the DC level measuring instrument 50 through the by results is performed. Hereinafter, the same applies. As described above, the output terminal T
_OUT1 to output terminal T The voltage appearing sequentially at _OUT160 is
The result is supplied to the C level measuring device 50, and the result is determined.
The test is completed. The test time is approximately as follows. Measurement time = number of output terminals x number of voltage value types x DC level per output terminal Test time = 160 x 4 x 10 ms = 6.4
s

[0004]

The above-mentioned DC parametric test apparatus has a relatively small size because it is constructed using a current generator, a voltage measuring device and a voltage generating and current measuring device. When testing an IC driven by a high voltage, it is difficult to easily perform a voltage level test with high accuracy and high speed, and the measurement time from the start to the end of the test is 6.4S. It was big.

The present invention provides a liquid crystal drive driver IC test apparatus which has solved the above-mentioned problems.

[0006]

[Means for Solving the Problems] A plurality of test voltages V ₁ -V
The selection of ₄ is performed by the test voltage changeover switches S _{V1 to} S _V4 , the selected test voltage V ₁ is supplied, and the resulting output voltage V _OUT1 is output by the output voltage control CLK synchronized with the test pattern. a large number of output terminals T _OUT1 ~ output terminal T of the terminal T _OUT1 ~ output constructed as appear sequentially to the terminal T _OUT160 LCD driver IC1 _OUT160
, The output terminal T _OUT of the liquid crystal drive driver IC1 is connected to the non-inverting input of the corresponding differential comparator 30, and the reference voltage V
A reference voltage circuit 20 for generating _REF1 (= V _{1 to} V ₄ ) in synchronization with an output voltage control CLK synchronized with a test pattern is provided. The output terminal of the reference voltage circuit 20 has an inverted input of each of the differential comparators 30. The output of the differential comparator 30 is connected to the input of each corresponding dual comparator 40, and the output of the dual comparator 40 is connected to the pass / fail judgment unit 60. 2. The liquid crystal driving driver IC testing apparatus according to claim 1, further comprising an attenuator 70 or 70 'at an inverting input and a non-inverting input of the differential comparator 30, respectively. LCD driver including a magnification amplifier 80 for compensating attenuation by an attenuator between the output of the dual comparator 40 and the input of the dual comparator 40 To constitute a C measuring device.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a liquid crystal drive driver IC test apparatus according to the present invention will be described with reference to FIG. The liquid crystal driving driver IC test apparatus according to the present invention is an IC1 to be tested.
Allowed to comprise a differential comparator 30 with the corresponding to each of the output terminal T _{OUT 1} ~ output terminal T _OUT160. The output terminal T _{OUT of} IC1 to be tested is connected to the non-inverting input of the corresponding differential comparator 30. 20 is a reference voltage circuit test voltage V ₁ ~V ₄ is input, the output is a differential comparator 3
0 is connected to the non-inverting input. The reference voltage V _REF is applied to the inverting input of the differential comparator 30 in synchronization with the application of the output voltage. The output of the differential comparator 30 is supplied to a dual comparator 40 provided correspondingly.
Note that the upper and lower reference voltages V of the dual comparator 40 are
_OL and V _OH are kept uniform.

Here, the liquid crystal drive driver IC testing apparatus according to the present invention also selects the relatively high test voltages V _{1 to} V ₄ to be inputted, as in the conventional example shown in FIG. _V1 was performed by to S _V4, the test voltage switched output voltage V _{OUT 1} is a switch S voltages V ₁ selected _V1 to the first first through its result is supplied to the liquid crystal driver IC1 is the output voltage control CLK , The output terminals T _OUT1 to T _OUT160 appear sequentially. The output voltage V _{OUT 1} sequentially at the output terminals T _OUT1 ~ output terminal T _OUT160 the differential comparator 30 _1-3
0 ₁₆₀ are supplied sequentially to the non-inverting input. In contrast, differential comparators 30 ₁ to 30 ₁₆₀ of the inverting input a reference voltage V _REF1 in synchronization with the output voltage control CLK synchronized from the output terminal of the reference voltage circuit 20 in the test pattern is (= V ₁₎ is Supplied. Here, the output of the differential comparator 30 is V _{O1 to} V _O160 = V _OUT −V _REF . The outputs of these differential comparators 30 are sequentially supplied to a dual comparator 40, and the outputs V _O1 .
The V _O160 is sequentially supplied to the pass / fail decision unit 60, where an IC that does not satisfy the pass condition is judged to be rejected. If the test voltage V ₂ ~V ₄ is selected is the same.

Assuming that the upper and lower voltage levels of the dual comparator 40 are V _OL and V _OH , the passing condition is V _OL ≦ V _O ≦ V _OH . The timing chart of the pass / fail judgment is as shown in FIG. In the example shown in FIG. 3, in the case of the output of V _OUT2 indicated by the chain line in the case of the reference voltage V _REF2 , the output level exceeds the voltage level V _OH , and it is determined that the output has failed.

Next, another embodiment of the present invention will be described with reference to FIG. In FIG. 4, the inverting input terminal and the non-inverting input terminal of the differential comparator 30 are provided with an attenuator 70 or 70 'of the attenuation ATT. Differential voltage between V _OUT and the reference voltage V _REF output from IC1 to be tested measured by in this way is caused to decay to 1 / ATT. By compensating for this attenuation by the subsequent stage magnification amplifier 80, the measurement accuracy can be improved. The accuracy of the difference voltage can be further improved by further increasing the attenuation and compensating for this by increasing the magnification of the subsequent stage magnification amplifier 80. Further, by multiplying the output of the differential comparator 30 by A, the error of the differential voltage can be reduced to 1 / A.

[0011]

By employing the differential comparator 30, it is possible to detect the difference voltage between the reference voltage V _REF and the output terminal voltage V _OUT of the IC 1 to be tested and measured with high accuracy, and to detect the difference voltage at the subsequent stage. The pass / fail judgment can be easily performed by the dual comparator 40.

According to the timing chart of the pass / fail judgment shown in FIG. 3, the measurement time from the start of measurement to the end of measurement is 4 ms. Therefore, the test time by the liquid crystal drive driver IC measurement device of the present invention employing the differential comparator device ÷ the test time by the DC parametric test device =
4 × 10 ⁻³ ÷ 6.4 = 1 ÷ 1600. That is, the reduction rate of the test time by the differential comparator device of the present invention is 1/1600 of the test time by the conventional DC parametric test device.

Further, an attenuator is provided at the input terminal of the differential comparator 30 to attenuate the difference voltage between V _OUT output from the IC 1 and the reference voltage V _REF, and this attenuation is made by a magnification amplifier 80 at the subsequent stage. By compensating, the accuracy of the difference voltage can be improved. Further, by multiplying the output of the differential comparator 30 by A, the error of the difference voltage can be reduced to 1 / A.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a conventional example of a liquid crystal drive driver IC measurement device.

FIG. 2 is a diagram illustrating an embodiment of the present invention.

FIG. 3 is a timing chart of pass / fail judgment.

FIG. 4 is a diagram illustrating another embodiment of the present invention.

[Explanation of symbols]

_SV test voltage changeover switch V _OUT output voltage CLK Output voltage control synchronized with test pattern T _OUT output terminal V _REF reference voltage 1 LCD driver IC 20 Reference voltage circuit 30 Differential comparator 40 Dual comparator 60 Pass / fail judgment unit 70 Attenuator 70 'Attenuator 80 Magnification amplifier

Claims (2)

(57) [Claims] 1. A test voltage selection switch is used to select a plurality of test voltages. The selected test voltage is supplied, and the resulting output voltage is sequentially output to a plurality of output terminals by an output voltage control CLK. And a differential comparator corresponding to each of a large number of output terminals of the liquid crystal drive driver IC. The output terminal of the liquid crystal drive driver IC is connected to the non-inverting input of the corresponding differential comparator. ,
A reference voltage circuit for generating a multiple reference voltage in synchronization with the output voltage control CLK. An output terminal of the reference voltage circuit is connected to each inverting input of the differential comparator. A liquid crystal driving driver IC test apparatus, wherein the input is connected to the input of each corresponding dual comparator, and the output of the dual comparator is connected to a pass / fail judgment device. 2. The liquid crystal drive driver IC test apparatus according to claim 1, further comprising an attenuator at each of an inverting input and a non-inverting input of the differential comparator, wherein an output of the differential comparator and an input of the dual comparator are provided. And a magnification amplifier for compensating for attenuation caused by the attenuator.