TWI804342B - Dynamic voltage switching testing method - Google Patents

Abstract

A dynamic voltage switching testing method is disclosed. The dynamic voltage switching testing method performs dynamic voltage switching test through the switching of the circuit internal signal, rather than merely pulling up the voltage for testing. The dynamic voltage switching testing method includes the following steps: (a) adding a voltage control circuit to a test circuit; and (b) when the voltage control circuit operates in a test mode, the voltage control circuit uses a voltage acceleration factor to make the test circuit perform dynamic voltage switching to speed up the reliability test.

Description

Dynamic Voltage Switching Test Method

The present invention is related to reliability testing of integrated circuits, in particular to a dynamic voltage switching (Dynamic Voltage Switching, DVS) testing method applied to source drivers.

Since the source driver is composed of a plurality of operational amplifiers, it is very important to ensure the production quality of this integrated circuit. The traditional reliability test method is to test the function of the operational amplifier body in the source driver and also take into account the quality test at the same time.

However, because the traditional method can only use the DC voltage acceleration factor and cannot cause voltage changes at the DC bias point, the quality test of the current source bias circuit cannot be accelerated and it is difficult to be detected in advance before shipment. Once the current source bias circuit has a defect in the production process of the integrated circuit, but it cannot be detected in advance before shipment, it is likely to cause the source driver to fail during the product warranty period, thus causing the customer's return rate greatly increased. This problem needs to be further resolved.

Therefore, the present invention proposes a dynamic voltage switching test method to effectively solve the above-mentioned problems encountered in the prior art.

A preferred embodiment of the present invention is a dynamic voltage switching test method. In this embodiment, the dynamic voltage switching test method includes the following steps: (a) Adding a voltage control circuit to the test circuit; and (b) when the voltage control circuit operates in the test mode, the voltage control circuit uses a voltage acceleration factor to make the test circuit perform dynamic voltage switching to speed up reliability testing.

In one embodiment, the test circuit is a current source bias circuit, the test circuit includes a plurality of DC bias points respectively coupled to a plurality of switches, the voltage control circuit controls the plurality of switches to turn on or off, so that the plurality of DC The bias point creates a potential difference.

In one embodiment, the test circuit includes a first transistor to a seventh transistor, the control ends of the first transistor and the second transistor are coupled to the first DC bias point, and the seventh transistor and the third transistor are connected to each other. The transistor is coupled between the working voltage and the ground voltage, the sixth transistor and the fourth transistor are coupled between the working voltage and the ground voltage, the fifth transistor and the first transistor are coupled between the working voltage and the ground voltage Between them, the control terminals of the third transistor and the fourth transistor are coupled to each other at the second DC bias point, the control terminals of the fifth transistor to the seventh transistor are coupled to each other at the third DC bias point, and the first One end of a switch is coupled to the first DC bias point and the other end is coupled between the fifth transistor and the first transistor; one end of the second switch is coupled to the second DC bias point and the other end is coupled to Connected between the seventh transistor and the third transistor, one end of the third switch is coupled to the third DC bias point and the other end is coupled between the sixth transistor and the seventh transistor.

In one embodiment, the voltage control circuit selectively operates in a normal operation mode or a different test mode according to the values of the first control signal and the second control signal.

In one embodiment, when the first control signal is 0 and the second control signal is 1, the voltage control circuit operates in the first test mode, and the voltage control circuit provides the first DC bias point to the third DC bias point The voltage values of the pressure points are 0, 0, and the working voltage respectively.

In one embodiment, when the first control signal is 1 and the second control signal is 0, the voltage control circuit operates in the second test mode, and the voltage control circuit provides the first DC bias point to the third DC bias point The voltage value of the pressure point is 0.

In one embodiment, when both the first control signal and the second control signal are 0, the voltage control circuit operates in the third test mode, and the voltage control circuit provides the first DC bias point to the third DC bias point The voltage value of the point is the working voltage.

In one embodiment, the test circuit is a level shifter bias circuit and includes a first output terminal and a second output terminal, respectively outputting a first voltage and a second voltage, and the voltage control circuit includes a first transistor to a second output terminal. Ten transistors, the first transistor and the second transistor are connected in series between the working voltage and the first output terminal, the eleventh transistor is coupled between the working voltage and the first output terminal, and the third transistor is connected in series Between the first output terminal and the ground voltage, the fourth transistor is coupled between the operating voltage and the first output terminal, the fifth transistor is coupled between the first output terminal and the ground voltage, and the sixth transistor is coupled connected between the working voltage and the second output terminal, the twelfth transistor is coupled between the second output terminal and the ground voltage, and the seventh transistor is coupled between the second output terminal and the control terminal of the twelfth transistor The eighth transistor is coupled between the control terminal of the twelfth transistor and the ground voltage, the ninth transistor is coupled between the second output terminal and the ground voltage, and the tenth transistor is coupled to the operating voltage and the second output terminal.

In one embodiment, the voltage control circuit operates in the first test mode and the second test mode respectively, so that the test circuit performs dynamic voltage switching to speed up the reliability test.

In one embodiment, in the first test mode, the voltage control circuit controls the second transistor, the third transistor, the fifth transistor, the sixth transistor, the seventh transistor and the ninth transistor to turn off, so that the The first voltage and the second voltage output by the first output terminal and the second output terminal are both working voltages.

In one embodiment, in the second test mode, the voltage control circuit controls the second transistor, the third transistor, the fourth transistor, the sixth transistor, the seventh transistor and the tenth transistor to turn off, so that the The first voltage and the second voltage output by the first output terminal and the second output terminal are both ground voltages.

In one embodiment, the dynamic voltage switching test method is to perform the dynamic voltage switching test by switching the internal signal of the circuit, rather than just pulling up the voltage for testing.

Compared with the previous technology, the dynamic voltage switching test method of the present invention is not just to pull up the voltage for static testing, but to perform dynamic voltage switching (DVS) testing through the switching of internal signals in the circuit, so as to speed up the reliability testing of products. Defective products can be checked out in advance when they are shipped, so it can effectively ensure that the quality of integrated circuit products will not break down during the warranty period, and greatly reduce the return rate of customers.

S10~S12: Steps

2: Current source bias circuit

M1~M7: first transistor~seventh transistor

A: The first DC bias point

B: The second DC bias point

C: The third DC bias point

D1~D3: switch

CON: voltage control circuit

AVDD: working voltage

AGND: ground voltage

C0: the first control signal

C1: Second control signal

I1: current

R: resistance

3: Level shifter bias circuit

OUT1: the first output terminal

OUT2: the second output terminal

VP: first voltage

VN: the second voltage

MT1~MT10: first transistor~tenth transistor

MP: eleventh transistor

MN: Twelfth Transistor

IA: current source

IB: current source

DE: Diode

LV_IN: Low voltage input signal

MP1~MP4: Transistor

MN1~MN2: Transistor

LVN1~LVN2: low voltage transistor

OUT: output terminal

OUTN: output terminal

FIG. 1 is a flowchart of a dynamic voltage switching test method according to a preferred embodiment of the present invention.

FIG. 2 is a schematic diagram of an embodiment of applying the dynamic voltage switching test method of the present invention to a current source bias circuit.

FIG. 3 is a schematic diagram of an embodiment of applying the dynamic voltage switching test method of the present invention to a level shifter bias circuit.

FIG. 4 and FIG. 5 are schematic diagrams of FIG. 3 operating in the first test mode and the second test mode, respectively.

A preferred embodiment of the present invention is a dynamic voltage switching test method. In this embodiment, the dynamic voltage switching test method can perform dynamic voltage switching on the source driver through the switching of the internal signal of the circuit to speed up the reliability test of the product, so as to detect defective products in advance when shipping, which is obviously different The traditional method of only pulling up the voltage for static testing, but not limited thereto.

Please refer to FIG. 1 . FIG. 1 shows a flow chart of the dynamic voltage switching test method in this embodiment. As shown in Figure 1, the dynamic voltage switching test method includes the following steps: Step S10: adding a voltage control circuit to the test circuit; and Step S12: when the voltage control circuit operates in the test mode, the voltage control circuit uses the voltage acceleration factor to make the test circuit Perform dynamic voltage switching to speed up reliability testing.

Please refer to FIG. 2 . FIG. 2 is a schematic diagram of an embodiment of a dynamic voltage switching test method applied to a current source bias circuit. As shown in FIG. 2 , the current source bias circuit 2 includes a plurality of DC bias points A~C respectively coupled to a plurality of switches D1~D3, and the voltage control circuit CON controls the plurality of switches D1~D3 to be turned on or off, so as to Make the multiple DC bias points A~C produce A potential difference is generated, thereby accelerating the aging of defective transistors and shortening the time required for product reliability testing.

It should be noted that in this embodiment, the voltage control circuit CON and switches D1~D3 are added to the current source bias circuit 2, and the voltage acceleration factor (AFV) is used to accelerate product reliability testing to ensure the quality of integrated circuit products . For example, the voltage acceleration factor (AFV) can be expressed as follows: AFV=exp(β*(Vstress-Vuse))=exp(1*(21-1))=1.41E+10

As shown in FIG. 2 , the current source bias circuit 2 includes a first transistor M1 to a seventh transistor M7 . The first transistor M1 to the fourth transistor M4 are N-type transistors, and the fifth transistor M5 to the seventh transistor M7 are P-type transistors. Control ends of the first transistor M1 and the second transistor M2 are coupled to a first DC bias point A. The current I1 flows through the second transistor M2. The seventh transistor M7 and the third transistor M3 are coupled between the operating voltage AVDD and the ground voltage AGND. The sixth transistor M6 and the fourth transistor M4 are coupled between the operating voltage AVDD and the ground voltage AGND. The resistor R is coupled between the fourth transistor M4 and the ground voltage AGND. The fifth transistor M5 and the first transistor M1 are coupled between the operating voltage AVDD and the ground voltage AGND. Control ends of the third transistor M3 and the fourth transistor M4 are coupled to the second DC bias point B. Control ends of the fifth transistor M5 to the seventh transistor M7 are coupled to the third DC bias point C. One end of the first switch D1 is coupled to the first DC bias point A and the other end is coupled between the fifth transistor M5 and the first transistor M1. One end of the second switch D2 is coupled to the second DC bias point B and the other end is coupled between the seventh transistor M7 and the third transistor M3. One end of the third switch D3 is coupled to the third DC bias point C and the other end is coupled between the sixth transistor M6 and the fourth transistor M4.

In practical applications, the voltage control circuit CON can selectively operate in the normal operation mode or different test modes according to the values of the first control signal C0 and the second control signal C1. The truth table of one embodiment is shown in Table 1 , but not limited to this.

As shown in Table 1, when the first control signal C0 is 0 and the second control signal C1 is 1, the voltage control circuit CON operates in the first test mode, and the voltage control circuit CON provides the first DC bias point A The voltage values up to the third DC bias point C are all zero. When the first control signal C0 is 1 and the second control signal C1 is 0, the voltage control circuit CON operates in the second test mode, and the voltage control circuit CON provides the first DC bias point A to the third DC bias The voltage values of point C are respectively 0, 0, and the working voltage AVDD. When the first control signal and the second control signal C1 are both 1, the voltage control circuit CON operates in the third test mode, and the voltage control circuit CON provides the first DC bias point A to the third DC bias point C The voltage values are the working voltage AVDD. From the above, it can be seen that this embodiment performs the dynamic voltage switching test through the switching of the internal signal of the circuit, which is obviously different from the traditional method of only pulling up the voltage for static testing.

Please refer to FIG. 3 . FIG. 3 is a schematic diagram of an embodiment of a dynamic voltage switching test method applied to a level shifter bias circuit.

As shown in FIG. 3 , the level shifter bias circuit 3 includes a first output terminal OUT1 and a second output terminal OUT2 for outputting a first voltage VP and a second voltage VN respectively. The voltage control circuit CON includes first to tenth transistors MT1 to MT10. The first transistor MT1 and the second transistor MT2 are connected in series between the working voltage AVDD and the first output terminal OUT1 . The eleventh transistor MP is coupled between the working voltage AVDD and the first output terminal OUT1. The third transistor MT3 and the current source IA are connected in series between the first output terminal OUT1 and the ground voltage AGND. The fourth transistor MT4 is coupled between the working voltage AVDD and the first output terminal OUT1 . The fifth transistor MT5 is coupled between the first output terminal OUT1 and the ground voltage AGND. The current source IB and the sixth transistor MT6 are connected in series between the working voltage AVDD and the second output terminal OUT2. The twelfth transistor MN is coupled between the second output terminal OUT2 and the ground voltage AGND. The seventh transistor MT7 is coupled between the second output terminal OUT2 and the control terminal of the twelfth transistor MN. The eighth transistor MT8 is coupled between the control terminal of the twelfth transistor MN and the ground voltage AGND. The ninth transistor MT9 is coupled between the second output terminal OUT2 and the ground voltage AGND. The tenth transistor MT10 is coupled between the working voltage AVDD and the second output terminal OUT2.

The transistors MP1, MP3, MN1 and LVN1 are connected in series between the working voltage AVDD and the ground voltage AGND. The transistors MP2, MP4, MN2 and LVN2 are connected in series between the working voltage AVDD and the ground voltage AGND. The control terminals of the transistors MP1 and MP2 are both coupled to the first output terminal OUT1. The control terminals of the transistors MN1 and MN2 are both coupled to the second output terminal OUT2. The control terminals of the transistors MP3 and MP4 are respectively coupled to the output terminals OUT and OUTN. Diode The body DE is coupled between the control terminals of the transistors LVN1 and LVN2. Transistors LVN1 and LVN2 are low-voltage transistor elements. The control terminal of the transistor LVN1 receives the low voltage input signal LV_IN.

It should be noted that in this embodiment, a voltage control circuit CON including the first transistor MT1 to the tenth transistor MT10 is added to the level shifter bias circuit 3, and the voltage acceleration factor (AFV) is used to accelerate product reliability. Degree testing to ensure the quality of integrated circuit products. For example, the voltage acceleration factor (AFV) can be expressed as follows: AFV=exp(β*(Vstress-Vuse))=exp(1*(21-1))=1.41E+10

In practical applications, the voltage control circuit CON can operate in the first test mode and the second test mode respectively, so that the level shifter bias circuit 3 can perform dynamic voltage switching to speed up the reliability test, but it does not limit.

As shown in Figure 4, in the first test mode, the voltage control circuit CON controls the second transistor MT2, the third transistor MT3, the fifth transistor MT5, the sixth transistor MT6, the seventh transistor MT7 and the ninth transistor The transistor MT9 is turned off, so that both the first output terminal OUT1 and the second output terminal OUT2 output the operating voltage AVDD, but not limited thereto.

As shown in Figure 5, in the second test mode, the voltage control circuit CON controls the second transistor MT2, the third transistor MT3, the fourth transistor MT4, the sixth transistor MT6, the seventh transistor MT7 and the tenth transistor The transistor MT10 is turned off, so that both the first output terminal OUT1 and the second output terminal OUT2 output the ground voltage AGND, but not limited thereto.

It should be noted that both the first output terminal OUT1 and the second output terminal OUT2 output the operating voltage AVDD in the first test mode and both output the ground voltage AGND in the second test mode, which can help ensure dynamic voltage switching (DVS ) to test the normal operation and protect the low-voltage transistors LVN1 and LVN2 at the same time.

Compared with the previous technology, the dynamic voltage switching test method of the present invention is not just to pull up the voltage for static testing, but to perform dynamic voltage switching (DVS) testing through the switching of internal signals in the circuit, so as to speed up the reliability testing of products. Defective products can be checked out in advance when they are shipped, so it can effectively ensure that the quality of integrated circuit products will not break down during the warranty period, and greatly reduce the return rate of customers.

S10~S12: Steps

Claims (5)

A dynamic voltage switching test method, comprising the following steps: (a) adding a voltage control circuit to a test circuit; and (b) when the voltage control circuit operates in a test mode, the voltage control circuit uses a voltage acceleration factor to make the test circuit perform Dynamic voltage switching to speed up the reliability test; wherein, the test circuit is a current source bias circuit, the test circuit includes a plurality of DC bias points respectively coupled to a plurality of switches, and the voltage control circuit controls the plurality of switches to be turned on or off, so that the plurality of DC bias points generate a potential difference; the test circuit includes a first transistor to a seventh transistor, and the control terminals of the first transistor and the second transistor are coupled to the first straight Current bias point, the seventh transistor and the third transistor are coupled between the operating voltage and the ground voltage, the sixth transistor and the fourth transistor are coupled between the operating voltage and the ground voltage , the fifth transistor and the first transistor are coupled between the operating voltage and the ground voltage, the control terminals of the third transistor and the fourth transistor are coupled to each other at a second DC bias point, The control ends of the fifth transistor to the seventh transistor are coupled to the third DC bias point, one end of the first switch is coupled to the first DC bias point and the other end is coupled to the fifth Between the transistor and the first transistor, one end of the second switch is coupled to the second DC bias point and the other end is coupled between the seventh transistor and the third transistor, and the third switch One end is coupled to the third DC bias point and the other end is coupled between the sixth transistor and the fourth transistor. The dynamic voltage switching test method as described in claim 1, wherein the voltage control circuit is selectively operated according to the values of the first control signal and the second control signal in normal operating mode or in different test modes. The dynamic voltage switching test method as described in claim 2, wherein when the first control signal is 0 and the second control signal is 1, the voltage control circuit operates in the first test mode, and the voltage control circuit provides The voltage values from the first DC bias point to the third DC bias point are all zero. The dynamic voltage switching test method as described in claim 2, wherein when the first control signal is 1 and the second control signal is 0, the voltage control circuit operates in the second test mode, and the voltage control circuit provides The voltage values from the first DC bias point to the third DC bias point are respectively 0, 0, and the working voltage. The dynamic voltage switching test method as described in claim 2, wherein when the first control signal and the second control signal are both 1, the voltage control circuit operates in a third test mode, and the voltage control circuit provides the The voltage values from the first DC bias point to the third DC bias point are all the operating voltages.

Images