Chip test protection system and chip calibration system based on TVS (Transient Voltage Suppressor)

Abstract

The invention relates to the technical field of integrated circuit testing, and provides a chip test protection system and a chip calibration system based on a TVS (Transient Voltage Suppressor) tube, and the test protection system comprises the TVS tube which is connected between a pin of a tested chip and the ground; the dynamic control module is connected between the TVS tube and the test signal source, and is configured to control the conduction or cut-off of the TVS tube according to the voltage change rate of the test signal source; wherein when the voltage at the two ends of the TVS tube exceeds the breakdown voltage of the TVS tube, the TVS tube is reversely broken down and conducted to form a low-impedance path, the pin voltage of the tested chip is clamped in a safe range, and when the voltage at the two ends of the TVS tube is smaller than the breakdown voltage of the TVS tube, the TVS tube is reversely cut off. According to the scheme, the dynamic control module regulates and controls the state of the TVS tube according to the voltage change rate of the test signal source, it is ensured that the TVS tube is rapidly conducted and protection is triggered in time when the voltage changes suddenly, the problem of lag caused by the fact that a piezoresistor depends on passive response is solved through the active response mechanism, and the timeliness and safety of the test protection system are improved.

Description

Technical Field

[0001] The present application relates to the technical field of integrated circuit testing, and in particular to a chip testing protection system and a chip calibration system based on a TVS tube. Background Art

[0002] ATE equipment (Automatic Test Equipment) is used to accurately measure the functionality and performance of semiconductor chips. It can automatically execute complex test procedures to verify that the chips meet design specifications. ATE equipment is equipped with a constant voltage source, and the output voltage and duration can be precisely controlled by the host computer software.

[0003] During testing, current ATE equipment generates voltage surges when the constant voltage source increases its voltage, potentially damaging the chip. To prevent this damage, varistors are often used as chip protection devices. However, varistors have a slow response to surges and low clamping accuracy, making them unable to stably limit the voltage to the limit. Furthermore, varistors age after repeated surges, weakening their suppression effectiveness and impacting long-term reliability.

[0004] Therefore, how to provide a chip testing and protection system with excellent security, high efficiency and reliability is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0005] The present application provides a chip test protection system and a chip calibration system based on TVS tubes, which utilize TVS tubes to clamp the chip pin voltage within a safe range, thereby improving the timeliness and safety of the test protection system.

[0006] The technical solution adopted in this application is:

[0007] In a first aspect, a chip test protection system based on a TVS tube is provided. The system includes an ATE device configured with a test signal source, the ATE device being used to test parameters of a chip under test, the test signal source being configured to output a test voltage to the chip under test, and the system further comprising:

[0008] A TVS tube is connected between the pin of the chip under test and the ground. When the voltage across the TVS tube exceeds its breakdown voltage, the TVS tube reversely breaks down and conducts to form a low-impedance path, thereby clamping the pin voltage of the chip under test within a safe range. When the voltage across the TVS tube is less than its breakdown voltage, the TVS tube reversely cuts off.

[0009] The dynamic control module is connected between the TVS tube and the test signal source and is configured to control the conduction or cutoff of the TVS tube according to the voltage change rate of the test signal source.

[0010] Preferably, the dynamic control module includes a monitoring unit and a control unit, the monitoring unit is configured to monitor the voltage of the test signal source in real time, and the control unit is configured to control the TVS tube to be turned on when the voltage change rate of the test signal source is greater than a first preset threshold.

[0011] Preferably, the dynamic control module also includes a time unit, and the control unit is configured to control the time unit to detect the stable duration of the test signal source when the voltage change rate of the test signal source is less than a first preset threshold value, and if the stable duration is greater than a second preset threshold value, control the TVS tube to be cut off.

[0012] Preferably, the TVS tube is a unidirectional structure or a bidirectional structure.

[0013] Preferably, the chip under test includes at least an SC pin, an SE pin, a TC pin, a COMP pin, a VCC pin, an IS pin, and a DC pin, and each pin is connected in parallel with the TVS tube and the test signal source.

[0014] Preferably, the system further comprises a filter capacitor connected in parallel to both ends of the TVS tube, configured to absorb transient surge current.

[0015] Preferably, the system further comprises a fuse connected in series between the TVS tube and the ground, configured to cut off the circuit in the event of an overcurrent fault.

[0016] Preferably, the clamping voltage of the TVS tube is set to 80% to 90% of the ultimate withstand voltage of the chip under test.

[0017] Preferably, the response time of the TVS tube is less than 1 ns.

[0018] In a second aspect, a chip calibration system is provided, comprising the TVS tube-based chip testing and protection system described in the first aspect.

[0019] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0020] The technical solution of the present application provides a chip test protection system and a chip calibration system based on a TVS tube, wherein the test protection system includes an ATE device configured with a test signal source, the ATE device is used to test the parameters of the chip under test, and the test signal source is configured to output a test voltage to the chip under test. The system also includes: a TVS tube, connected between the pin of the chip under test and the ground; a dynamic control module, connected between the TVS tube and the test signal source, and configured to control the conduction or cutoff of the TVS tube according to the voltage change rate of the test signal source; wherein, when the voltage across the TVS tube exceeds its breakdown voltage, the TVS tube reversely breaks down and conducts to form a low-impedance path, clamping the pin voltage of the chip under test within a safe range, and when the voltage across the TVS tube is less than its breakdown voltage, the TVS tube reversely cuts off. In this solution, the TVS tube is combined with a dynamic control module to overcome the defects of the varistor such as slow response, poor clamping accuracy, and susceptibility to aging. The dynamic control module adjusts the state of the TVS tube according to the voltage change rate of the test signal source, ensuring that the TVS tube is quickly turned on when the voltage suddenly changes, triggering protection in time. The TVS tube is used to clamp the chip pin voltage within a safe range. This active response mechanism avoids the hysteresis problem of the varistor relying on passive response, improving the timeliness and safety of the test protection system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is a circuit diagram of the connection between the chip under test, the TVS tube and the test signal source provided in an embodiment of the present application;

[0023] Figure 2 This is a flow chart of determining whether to turn on or off a TVS tube, as provided in an embodiment of the present application. DETAILED DESCRIPTION

[0024] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0025] As described in the background, current ATE equipment can generate voltage surges during testing when the constant voltage source increases its voltage, damaging the chip. To prevent this damage, varistors are typically used as chip protection devices. However, varistors have a slow response to surges and low clamping accuracy, making it difficult to stably limit the voltage to the limit. Furthermore, varistors age after repeated surges, resulting in a weakened suppression effect and impacting long-term reliability.

[0026] Based on this, the present application provides a chip testing protection system and a chip calibration system based on TVS tubes, aiming to solve the technical problem of poor effect of using varistors as protection devices in the prior art.

[0027] Example 1

[0028] Embodiment 1 of the present application provides a chip test protection system based on a TVS tube. The system includes an ATE device configured with a test signal source, the ATE device is used to test the parameters of the chip under test, and the test signal source is configured to output a test voltage to the chip under test. The system also includes: a TVS tube, connected between a pin of the chip under test and ground; a dynamic control module, connected between the TVS tube and the test signal source, and configured to control the conduction or cutoff of the TVS tube according to the voltage change rate of the test signal source; wherein, when the voltage across the TVS tube exceeds its breakdown voltage, the TVS tube reversely breaks down and conducts to form a low-impedance path, clamping the pin voltage of the chip under test within a safe range; when the voltage across the TVS tube is less than its breakdown voltage, the TVS tube reversely cuts off.

[0029] Without the dynamic control module, the TVS diode can still provide protection when transient voltage exceeds its breakdown voltage, limiting voltage peaks by rapidly conducting to prevent damage to the chip under test. However, in some cases, normal voltage fluctuations may cause the TVS diode to trigger unnecessarily, affecting test accuracy. With the addition of the dynamic control module, the system can more flexibly protect the chip. By monitoring the rate of voltage change, the TVS diode is triggered only when an abnormally rapid rise (such as a surge or spike) is detected, avoiding false triggering during normal operation. By reducing the number of unnecessary triggering, the TVS diode's service life is extended and maintenance costs are reduced.

[0030] It should be noted that the operating parameters of the TVS tube, such as clamping voltage, breakdown voltage, reverse cutoff voltage, reverse current, peak pulse current, etc., are all selected according to the electrical characteristics of the chip under test.

[0031] In a specific embodiment, a chip test protection system based on a TVS tube is applied to the test process of a 30V-powered industrial version of a shift register. The TVS tube is connected between each key pin of the chip under test and the ground to absorb and release potential instantaneous voltage spikes (voltage exceeding 30V). The dynamic control module monitors the voltage change rate from the test signal source in real time. When it is detected that the voltage instantaneously exceeds the set safety range, the TVS tube responds quickly, reversely breaks down to form a low-impedance path, and clamps the excessive voltage within a safe level, thereby effectively protecting the shift register from possible surge damage and improving the stability and reliability of the test process.

[0032] In a specific embodiment, referring to Figure 1 There are multiple TVS tubes, which are respectively denoted as D1 to D7. The chip under test uses a power management chip, which includes an SC pin, a SE pin, a TC pin, a GND pin, a COMP pin, a VCC pin, an IS pin, and a DC pin. The SC pin is connected in parallel with D1 and a test signal source (VI_SOURCE), the SE pin is connected in parallel with D2 and a test signal source, the TC pin is connected in parallel with D3 and a test signal source, the COMP pin is connected in parallel with D4 and a test signal source, the VCC pin is connected in parallel with D5 and a test signal source, the IS pin is connected in parallel with D6 and a test signal source, and the DC pin is connected in parallel with D7 and a test signal source. Among them, D5 selects a 40V TVS tube, and D1 to D4, D6, and D7 all select 5V TVS tubes. The aforementioned SC pin is the collector lead of the internal switch tube Q1, the SE pin is the emitter lead of the internal switch tube Q1, the TC pin is the timing capacitor connection terminal, the GND pin is the power ground terminal, the COMP pin is the comparator inverting input / output voltage sampling terminal, the VCC pin is the positive power input terminal, the IS pin is the peak current sampling terminal, and the DC pin is the collector lead of the internal driver tube Q2.

[0033] Preferably, reference Figure 2 The dynamic control module includes a monitoring unit and a control unit. The monitoring unit is configured to monitor the voltage of the test signal source in real time. The control unit is configured to control the TVS tube to be turned on when the voltage change rate (dv / dt) of the test signal source is greater than a first preset threshold.

[0034] In a specific embodiment, the first preset threshold of the shift register is set to a voltage change of 5V / μs per microsecond. When the test voltage of the test signal source suddenly rises from 28V to 35V, that is, the voltage change rate is 7V / μs, which exceeds the preset 5V / μs, the TVS tube is quickly turned on to clamp the voltage within a safe range.

[0035] In a specific embodiment, the TVS tube is connected to the circuit through an electronic switch. The control unit can send control instructions to the electronic switch to control the state of the TVS tube. For example, when the TVS tube needs to be turned on, the control unit can send a high-level signal to the electronic switch to turn on the electronic switch, thereby allowing the TVS tube to be connected to the circuit.

[0036] Preferably, reference Figure 2 The dynamic control module also includes a time unit. The control unit is configured to control the time unit to detect the stable duration of the test signal source when the voltage change rate of the test signal source is less than the first preset threshold. If the stable duration is greater than the second preset threshold, the TVS tube is controlled to be cut off.

[0037] In a specific embodiment, the second preset threshold is set to 10ms. At a certain moment, the voltage change rate drops from the previous 7V / μs to 2V / μs. The monitoring unit transmits the monitored information to the control unit. The control unit activates the time unit to start timing and records whether the current voltage can remain stable for more than 10ms. If so, the control unit controls the TVS tube to cut off to exit the protection mode. If not, the control unit controls the TVS tube to continue to remain on to provide necessary protection.

[0038] Preferably, the TVS tube is a unidirectional TVS tube or a bidirectional TVS tube.

[0039] Unidirectional TVS diodes are suitable for DC or signal transmission in only one direction, while bidirectional TVS diodes are suitable for AC or signal transmission in both directions. The chip under test in this embodiment has multiple interfaces and signal types, each subject to different types of transient interference. Therefore, bidirectional TVS diodes are used to provide protection for various interface types, enhancing the system's versatility and reliability.

[0040] Preferably, the system further includes a filter capacitor connected in parallel to both ends of the TVS tube, configured to absorb transient surge current; the system further includes a fuse connected in series between the TVS tube and the ground, configured to cut off the circuit in the event of an overcurrent fault.

[0041] In one specific embodiment, when a test signal source outputs a sudden voltage pulse to the shift register, rising from 28V to 35V, and the monitoring unit detects that the voltage change rate exceeds a first preset threshold of 5V / μs, the control unit controls the TVS diode to conduct. Simultaneously, the sudden voltage change causes a transient surge current, which the filter capacitor immediately absorbs, mitigating the impact on the shift register and helping to stabilize the voltage. If an unexpected short circuit occurs during this process, causing the current to rise sharply beyond the safe value of the shift register, the fuse will quickly blow, disconnecting the circuit to prevent further damage.

[0042] Preferably, the clamping voltage of the TVS tube is set to 80% to 90% of the ultimate withstand voltage of the chip under test, and the response time of the TVS tube is less than 1 ns.

[0043] The TVS diode activates in less than 1ns and limits the voltage to a safe range, effectively preventing damage to the chip under test caused by voltage surges. By setting the clamping voltage range, the chip under test is protected while minimizing system performance degradation caused by excessive clamping, providing safety without affecting normal operation.

[0044] Example 2

[0045] A second embodiment of the present application provides a chip calibration system, including the TVS tube-based chip testing and protection system in the first embodiment.

[0046] In one specific embodiment, a chip calibration system is used during the calibration of an ADC chip. The ATE equipment supplies voltage to the ADC chip via a test signal source and compares the ADC chip's output value with a preset value. If the two values ​​match, the chip is normal. If the two values ​​do not match, the ADC chip's output value is adjusted to match the preset value to achieve chip calibration. A TVS diode is connected between the ADC pin and ground. A dynamic control module monitors the TVS diode's state in real time and controls it based on the voltage change rate of the test signal source to prevent transient high voltage from damaging the ADC chip. When the voltage is detected to exceed the safety threshold, the TVS diode quickly turns on, clamping the voltage within a safe range and ensuring a smooth calibration process.

[0047] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0049] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A chip test protection system based on a TVS tube, the system comprising an ATE device configured with a test signal source, the ATE device being used to test parameters of a chip under test, the test signal source being configured to output a test voltage to the chip under test, characterized in that: The system further comprises: A TVS tube is connected between the pin of the chip under test and the ground; a dynamic control module, connected between the TVS tube and the test signal source, and configured to control the on or off state of the TVS tube according to the voltage change rate of the test signal source; Among them, when the voltage across the TVS tube exceeds its breakdown voltage, the TVS tube reversely breaks down and conducts to form a low-impedance path, clamping the pin voltage of the chip under test within a safe range. When the voltage across the TVS tube is less than its breakdown voltage, the TVS tube reversely cuts off.

2. The chip testing and protection system based on TVS tube according to claim 1, characterized in that: The dynamic control module includes a monitoring unit and a control unit. The monitoring unit is configured to monitor the voltage of the test signal source in real time. The control unit is configured to control the TVS tube to be turned on when the voltage change rate of the test signal source is greater than a first preset threshold.

3. The chip testing and protection system based on TVS tube according to claim 2, characterized in that: The dynamic control module also includes a time unit, and the control unit is configured to control the time unit to detect the stable duration of the test signal source when the voltage change rate of the test signal source is less than a first preset threshold value, and if the stable duration is greater than a second preset threshold value, control the TVS tube to be cut off.

4. The chip testing and protection system based on TVS tube according to any one of claims 1 to 3, characterized in that: The TVS tube is a unidirectional TVS tube or a bidirectional TVS tube.

5. The chip testing and protection system based on TVS tube according to any one of claims 1 to 3, characterized in that: The chip under test includes at least an SC pin, an SE pin, a TC pin, a COMP pin, a VCC pin, an IS pin, and a DC pin, and each pin is connected in parallel with the TVS tube and the test signal source.

6. The chip testing and protection system based on TVS tube according to claim 5, characterized in that: The system further includes a filter capacitor connected in parallel to both ends of the TVS tube and configured to absorb transient surge current.

7. The chip testing and protection system based on TVS tube according to claim 6, characterized in that: The system further includes a fuse connected in series between the TVS tube and the ground, configured to cut off the circuit in the event of an overcurrent fault.

8. The chip testing and protection system based on TVS tube according to any one of claims 1 to 3, characterized in that: The clamping voltage of the TVS tube is set to 80% to 90% of the ultimate withstand voltage of the chip under test.

9. The chip testing and protection system based on TVS tube according to any one of claims 1 to 3, characterized in that: The response time of the TVS tube is less than 1 ns.

10. A chip calibration system, characterized in that: The chip test protection system comprises the TVS tube-based system as claimed in any one of claims 1 to 9.

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