A method for determining junction temperature of a MOSFET device dynamic test, a circuit, and a test unit

Abstract

The present invention provides a method for determining the junction temperature of a MOSFET device in a dynamic test, and relates to the technical field of electronic device testing. The method comprises: building a test circuit for the dynamic test of the MOSFET device, wherein a target MOSFET device is located in the test circuit; pre-fitting a tube voltage drop versus temperature curve of the target MOSFET device under a reference current, wherein the reference current is much smaller than a test current during testing; using the test circuit to perform a test, and reversely injecting the reference current into the target MOSFET device during testing to obtain a real-time tube voltage drop of the target MOSFET device under testing, and determining the junction temperature of the target MOSFET device according to the tube voltage drop versus temperature curve of the target MOSFET device, so as to solve the problem of lack of accurate acquisition of the junction temperature of the MOSFET device during short circuit / double pulse testing.

Description

Technical Field

[0001] The invention relates to the technical field of electronic device testing, and in particular to a junction temperature determination method and a test circuit for dynamic testing of a MOSFET device. Background Art

[0002] MOSFET devices have many advantages such as high integration, simple design, and reliable performance, and are widely used in the fields of electronics and power electronics. MOSFET devices affect the speed and driving ability of the entire electronic system, so it is very necessary to perform dynamic performance tests on MOSFET devices, such as double pulse tests / short circuit tests, etc.

[0003] In the short-circuit / double-pulse test of MOSFET devices, the performance of MOSFET devices under specific conditions can be evaluated; however, large power consumption will be generated during the device testing process, and the junction temperature will increase. The junction temperature of existing MOSFET devices is often determined through separate heat dissipation or aging tests. In the short-circuit / double-pulse test of MOSFET devices, the device temperature is only obtained through temperature measuring guns, infrared temperature measurement, etc., with low accuracy. Therefore, there is a lack of methods to accurately obtain the junction temperature of MOSFET devices during short-circuit / double-pulse tests. Summary of the invention

[0004] In order to overcome the above technical defects, the purpose of the present invention is to provide a junction temperature determination method and test circuit for dynamic testing of MOSFET devices, so as to solve the existing problem of lack of accurate acquisition of the junction temperature of MOSFET devices during short circuit / double pulse testing.

[0005] The present invention discloses a method for determining junction temperature of a MOSFET device dynamic test, comprising:

[0006] Building a test circuit for dynamic testing of MOSFET devices, wherein a target MOSFET device is located in the test circuit;

[0007] Pre-fitting a curve of the tube voltage drop versus temperature of the target MOSFET device under a reference current, wherein the reference current is much smaller than the test current during the test;

[0008] The test circuit is used to perform the test, and during the test, the reference current is reversely injected into the target MOSFET device to obtain the real-time tube voltage drop of the target MOSFET device under the test, and the junction temperature of the target MOSFET device is determined according to the tube voltage drop versus temperature curve of the target MOSFET device.

[0009] Preferably, the reference current is at mA level and does not exceed 10 mA.

[0010] Preferably, a reference current is injected into the MOSFET device at different temperatures, and a corresponding tube voltage drop is obtained to fit a tube voltage drop versus temperature curve of the target MOSFET device.

[0011] Preferably, the target MOSFET device is heated / cooled at a uniform rate so that the target MOSFET device is at different temperatures.

[0012] Preferably, after the test circuit is constructed, a power supply circuit for providing the reference current is connected to the test circuit, and the reference current is opposite to the test current generated when the test circuit performs a test.

[0013] Preferably, when no test is performed, a curve of tube voltage drop versus temperature variation of the target MOSFET device is fitted offline.

[0014] The present invention also provides a circuit for dynamic testing of MOSFET devices.

[0015] including a test circuit for performing a target MOSFET device test and a power supply circuit for providing a reference current;

[0016] The test circuit includes a power supply terminal and a target MOSFET device and an auxiliary MOSFET device connected in series;

[0017] The target MOSFET device and the auxiliary MOSFET device are cooperatively turned off to perform a dynamic test;

[0018] The power supply circuit is connected to the target MOSFET device to provide a reference current to the target MOSFET device;

[0019] It also includes: executing any of the above-mentioned methods for determining junction temperature of a MOSFET device dynamic test to obtain the junction temperature of the target MOSFET device.

[0020] Preferably, the test circuit further comprises an inductor connected in parallel with the auxiliary MOSFET device.

[0021] Preferably, the test circuit further comprises a collection device for collecting a tube voltage drop of the target MOSFET device.

[0022] Preferably, the acquisition device includes a voltage acquisition device or a voltage acquisition circuit.

[0023] The present invention also provides a test unit, comprising any one of the MOSFET device dynamic test circuits, used for short-circuit testing and / or double-pulse testing of MOSFET devices.

[0024] Compared with the prior art, the above technical solution has the following beneficial effects:

[0025] The present application provides a method and circuit for determining junction temperature of a MOSFET device in a dynamic test, and a test unit. During the dynamic test of the MOSFET device, a tube voltage drop versus temperature curve of a target MOSFET device under a small current (reference current) is pre-fitted. During the test, the junction temperature of the target MOSFET device is determined according to the tube voltage drop detected after a small current is reversely injected. The characteristic that the tube voltage drop of the MOSFET device changes linearly with the temperature under a small current is utilized to accurately determine the junction temperature during the dynamic test of the MOSFET device, and the tolerance of the MOSFET device under short-term high-temperature conditions can be determined. In the present application, a small current power supply circuit for the target MOSFET device can be added based on the test circuit, and the accuracy of the junction temperature measurement of the MOSFET device can be improved without damaging the MOSFET device. Further fitting of the tube voltage drop versus temperature curve of the target MOSFET device under a small current (reference current) can also be achieved offline in an untested state based on the test circuit. The operation is simple, and there is no need to build an additional test circuit or test the junction temperature separately, which effectively improves the test efficiency and solves the existing problem of lack of accurate acquisition of the junction temperature of the MOSFET device during short-circuit / double-pulse testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A flowchart of a method for determining junction temperature of a MOSFET device dynamic test according to the present invention, a circuit, and a test unit embodiment 1 of the method for determining junction temperature;

[0027] Figure 2 A schematic diagram of a method and circuit for determining junction temperature of a MOSFET device dynamic test and a circuit for testing a unit in Embodiments 1 and 2 of the present invention;

[0028] Figure 3 The present invention provides a method and circuit for determining junction temperature of a MOSFET device in dynamic testing, and a test unit embodiment 1 and 2, showing a curve of the tube voltage drop of a target MOSFET device changing with temperature under a reference current.

[0029] Reference numerals:

[0030] M1-target MOSFET device; M2-auxiliary MOSFET device. DETAILED DESCRIPTION

[0031] The advantages of the present invention are further described below in conjunction with the accompanying drawings and specific embodiments.

[0032] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0033] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. The singular forms of "a", "said" and "the" used in this disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0034] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0035] In the description of the present invention, it is necessary to understand that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0036] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0037] In the following description, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present invention, and have no specific meanings. Therefore, "module" and "component" can be used interchangeably.

[0038] Example 1: This embodiment discloses a method for determining the junction temperature of a MOSFET device during dynamic testing, which can accurately extract the chip junction temperature without destroying the device (different from the existing aging test, which requires destroying the device to obtain its maximum temperature tolerance) and without the need for other temperature detection equipment. Specifically, the MOSFET device is extracted during the double pulse / short circuit test. Figure 1-Figure 3 ,include:

[0039] S10: constructing a test circuit for dynamic testing of MOSFET devices, wherein the target MOSFET device is located in the test circuit;

[0040] Specifically, the test circuit refers to the following embodiment 2, and the test circuit is used to implement dynamic testing of MOSFET devices, such as double pulse / short circuit testing. It can be understood that the existing general circuits for implementing the aforementioned tests can be used, and other test circuits except the aforementioned can also be used to determine the junction temperature of the MOSFET device.

[0041] It should also be noted that the method for determining the junction temperature provided in this embodiment depends on the characteristics of the MOSFET device. The on-resistance of the specific MOSFET device has a positive temperature coefficient, that is, as the junction temperature increases, the on-resistance will increase, as well as the reverse conduction characteristic. Therefore, this junction temperature determination method is only used for MOSFET devices.

[0042] S20: Pre-fitting the tube voltage drop V of the target MOSFET device under the reference current ds The temperature variation curve, wherein the reference current is much smaller than the test current during the test;

[0043] Specifically, in this embodiment, the reverse conduction characteristic of the MOSFET device diode is used to inject a reference current. Since the relationship between the voltage drop of the diode and the junction temperature is usually linear under a small current, and this characteristic is a characteristic of the MOSFET device diode itself, this characteristic is used in this embodiment. For a test sample (i.e., the above-mentioned target MOSFET device), a small current (i.e., a reference current much smaller than the test current during the test) is injected at any temperature, and the tube voltage drop V is read. ds , adjust the temperature and measure multiple times to establish a linear relationship between temperature (junction temperature) and tube voltage drop.

[0044] It can be understood that the above-fitted curve of the tube voltage drop of the target MOSFET device with temperature variation (see Figure 3) is used to determine the junction temperature in real time during the double pulse / short circuit test process in the next step. It should be noted that the reference current is much smaller than the test current during the test, and the reference current is mA level and does not exceed 10mA. On the one hand, due to the above characteristics, when the current is large, it may deviate from the linear relationship due to other reasons. On the other hand, since the real-time junction temperature is tested during the double pulse / short circuit test process, setting a current much smaller than it reduces the impact on the test process.

[0045] In the above steps, the purpose is to pre-calibrate the tube voltage drop variation curve of the target MOSFET device with temperature. It can be understood that the tube voltage drop variation curve of the target MOSFET device can be provided in advance, that is, obtained through existing tests or pre-stored and retrieved from a database. In this embodiment, a reference current is injected into the MOSFET device at different temperatures in advance, and the corresponding tube voltage drop is obtained to fit the tube voltage drop variation curve of the target MOSFET device with temperature. Specifically, the target MOSFET device can be heated / cooled at a uniform rate so that the target MOSFET device is at different temperatures. Specifically, as an example, the test circuit can be directly set in a certain environmental chamber without performing a test, and the ambient temperature of the MOSFET device is controlled to change uniformly. At this time, the ambient temperature and the junction temperature of the MOSFET device can be regarded as the same. The uniform temperature change can be controlled to take multiple temperature points. As mentioned above, a linear change is usually maintained. Therefore, as an example, at least three temperature points can be obtained for fitting.

[0046] It should be emphasized that the above-mentioned fitting curve of the tube voltage drop variation with temperature of the target MOSFET device is obtained before the test is performed below. It is related to the MOSFET device itself and will not affect the test process. The obtained curve (result) can be integrated in the test process to determine the junction temperature.

[0047] S30: Perform the test using the test circuit, reversely inject the reference current into the target MOSFET device during the test, obtain the real-time tube voltage drop of the target MOSFET device under the test, and determine the junction temperature of the target MOSFET device according to the tube voltage drop versus temperature curve of the target MOSFET device.

[0048] In this embodiment, the reference current is injected in reverse during testing, so as to determine the junction temperature of the target MOSFET device based on the detected real-time tube voltage drop (obtained directly based on the above-mentioned fitting curve). It can be understood that reverse means that the reference current is opposite to the test current generated when the test circuit performs the test. Specifically, after the test circuit is built, a power supply circuit for providing the reference current is connected to the test circuit, and the reference current is opposite to the test current generated when the test circuit performs the test.

[0049] As an illustration, the reference current is opposite to the test current generated when the test circuit performs the test. Firstly, the existence of the diode on the MOSFET device can be achieved through the power supply circuit. Secondly, the current reversal will not affect the test current.

[0050] It is understandable that the aforementioned pre-injection of reference current into the MOSFET device at different temperatures and the acquisition of the corresponding tube voltage drop to fit the tube voltage drop versus temperature curve of the target MOSFET device can be realized by pre-building a circuit (and storing the curve after obtaining it for calling during the test process). It can also be preferred that the circuit does not need to be rebuilt, and it can be realized by simply adding the above-mentioned power supply circuit based on the test circuit, and the tube voltage drop versus temperature curve of the target MOSFET device can be fitted offline (in advance) when the test is not performed. After the test is performed, the power supply circuit can also be kept turned on to directly determine the junction temperature.

[0051] As described above, based on the test circuit and the power supply circuit, it is possible to pre-fit the tube voltage drop versus temperature curve of the target MOSFET device and then perform the test. During this process, there is no need to change the test circuit, and the power supply circuit can be directly kept turned on, thereby achieving circuit sharing in double pulse testing / short-circuit testing and junction temperature determination, thereby improving test efficiency.

[0052] In this embodiment, during the double pulse / short circuit test, the target MOSFET device will generally heat up rapidly in a relatively short period of time and cool down in a relatively long period of time. Therefore, the junction temperature can be determined within a short period of time after the test is executed to a period of time after the test ends, which can achieve a μs / ms level junction temperature determination response after the test. Determining the junction temperature during the test can determine the tolerance of the MOSFET device to short-term high-temperature conditions, thereby providing a reference for subsequent designs applied to this condition. In addition to this, verification during the test process can be further achieved, such as being applied to a power device heating simulation model, thereby accurately obtaining the device state during the dynamic test process.

[0053] Based on the above, the present embodiment utilizes the characteristic that the relationship between the forward voltage drop and the junction temperature of the diode of the MOSFET device under a small current is usually linear, and a small current (the above-mentioned reference current) is injected into the target MOSFET device in advance to establish a linear relationship between temperature and tube voltage drop, and the tube voltage drop curve of the target MOSFET device is fitted with the temperature change curve. During the test, the junction temperature of the target MOSFET device is determined according to the tube voltage drop detected after the reverse injection of the small current (the above-mentioned reference current). Specifically, based on the test circuit, a power supply circuit for the target MOSFET device can be added, and the accuracy of the junction temperature measurement is guaranteed without damaging the MOSFET device; at the same time, it can realize the rapid extraction of the chip junction temperature during the short-circuit test, and then obtain the junction temperature rise of the MOSFET device during the short-circuit process, which is of great significance for obtaining the short-circuit parameters and safe working area of ​​the sample, and the operation is simple and the results are accurate.

[0054] As a supplement, this embodiment utilizes the characteristic that the relationship between the forward voltage drop of the diode and the junction temperature of the MOSFET device diode at a small current is usually linear. This characteristic is a common expression in the art. Specifically, as an example, if the voltage drop of the diode at a certain reference temperature is V ds-0 , then the voltage drop V after the temperature change ΔT ds , V can be calculated by the following formula ds =V ds-0 -α·ΔT, α is the temperature coefficient, usually 2-2.5mV / °C, and ΔT is the temperature change (in degrees Celsius). Therefore, this embodiment adds junction temperature determination during the dynamic test of the MOSFET device, establishes the relationship between the voltage drop of the MOSFET device and the junction temperature, and extracts its junction temperature during the test, that is, obtains the junction temperature of the MOSFET device during the test according to the real-time voltage drop.

[0055] Embodiment 2: The present invention also provides a circuit for dynamic testing of a MOSFET device, the test circuit executing the method for determining the junction temperature of the MOSFET device dynamic test described in any one of the above embodiments 1 (such as Figure 1 ) determines the junction temperature of the target MOSFET device during dynamic testing.

[0056] For details, see Figure 2-Figure 3 , including a test circuit for performing dynamic testing of a target MOSFET device and a power supply circuit for providing a reference current; the test circuit includes a power supply terminal and a target MOSFET device and an auxiliary MOSFET device connected in series; the target MOSFET device and the auxiliary MOSFET device are shut down in coordination to perform dynamic testing; the power supply circuit is connected to the target MOSFET device to provide a reference current to the target MOSFET device.

[0057] In this embodiment, the test circuit is used to perform tests. It can be understood that, as mentioned above, the test circuit can be used to implement dynamic testing of MOSFET devices, such as double pulse / short circuit testing, and other test circuits other than the aforementioned can also be used to determine the junction temperature of the MOSFET device.

[0058] like Figure 2 As described above, the power supply end (not marked in the figure, only shown as a power symbol) supplies power to the target MOSFET device M1 and the auxiliary MOSFET device M2 for testing, and the power supply circuit is connected to the target MOSFET device M1 to reversely provide a reference current and obtain the voltage drop V ds .

[0059] Specifically, in order to realize the double pulse / short circuit test of MOSFET devices, the test circuit also includes an inductor connected in parallel with the auxiliary MOSFET device. The target MOSFET device and the auxiliary MOSFET device are turned off in coordination. For example, in the initial state of the test, the target MOSFET device is in the ON state and the auxiliary MOSFET device is in the OFF state. The test current is obtained, and the states of the target MOSFET device and the auxiliary MOSFET device are adjusted for testing. At this time, a large test current is used, which may even reach several thousand mA. The reference current is at the mA level and does not exceed 10 mA. It is in the opposite direction of the test current. Therefore, the reference current will not affect the test process, and the circuit can be shared in the double pulse test / short circuit test and junction temperature determination.

[0060] It can be understood that the above-mentioned target MOSFET device and auxiliary MOSFET device can be interchanged so as to interchange different MOSFET devices. It can be understood that the above-mentioned fitted tube voltage drop versus temperature curve of the (target) MOSFET device is related to the MOSFET device itself. Therefore, when the same type of MOSFET devices does not need to be re-fitted, different types of MOSFET devices need to be curve fitted before performing the test.

[0061] It can be understood that, as mentioned above, the curve of the tube voltage drop varying with temperature of the (target) MOSFET device can be obtained in advance (the circuit can be rebuilt to achieve fitting / obtained by other testing methods / the fitted curve can be directly obtained from a preset database), or it can be directly based on the test circuit and the power supply circuit. When not tested (before testing), the ambient temperature of the target MOSFET device can be adjusted to perform offline fitting. There is no need to rebuild the circuit, realize circuit sharing, and keep the power supply circuit always connected. Only the test environment and execution signal can be adjusted, which is simple to operate.

[0062] In this embodiment, the tube voltage drop of the target MOSFET device is directly acquired by a device or a circuit, and the specific test circuit also includes a collection device for collecting the tube voltage drop of the target MOSFET device. Optionally, the collection device includes a voltage collection device (such as a voltage external meter, etc.) or a voltage collection circuit, and any existing circuit that can realize voltage drop collection can be used.

[0063] Specifically, based on the circuit of this embodiment, based on the linear relationship between the diode voltage drop and the junction temperature under a small current, the body diode of the MOSFET device is used to inject a small current and measure the voltage drop across the MOSFET device to obtain the chip junction temperature. As an example, the temperature of the sample under test (including the target MOSFET device) is uniformly changed to stabilize it at the target temperature as a whole. At this time, the junction temperature of the MOSFET device is equal to the sample temperature; a small current source is passed at a given temperature, and the sample V ds ; Take at least three temperature points and fit the temperature-V ds Graph (see Figure 3 ); before and after the double pulse / short circuit test, a small current source is passed to measure the Vds of the sample at that time; and the junction temperature of the MOSFET device at that time is determined by comparing the temperature-Vds curve above.

[0064] Furthermore, this embodiment also provides a test unit, including any of the above-mentioned MOSFET device dynamic test circuits, for short-circuit testing and / or double-pulse testing of MOSFET devices. It is understandable that the above-mentioned test circuit is mainly suitable for short-circuit testing and / or double-pulse testing of MOSFET devices; it can also be applied to other test scenarios, in which case the test circuit needs to be replaced with a circuit adapted to the test target (other performance indicators); it can also be connected or integrated with other equipment / devices / circuits as an independent unit, or applied in batches, so as to be suitable for different test conditions, provide accurate data support for subsequent devices, and improve work efficiency.

[0065] It should be noted that the embodiments of the present invention have better practicability and do not impose any form of limitation on the present invention. Any technician familiar with the field may use the technical content disclosed above to change or modify it into an equivalent effective embodiment. However, any modification or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for determining junction temperature of a MOSFET device dynamic test, characterized in that: include: Building a test circuit for dynamic testing of MOSFET devices, wherein a target MOSFET device is located in the test circuit; Pre-fitting a curve of the tube voltage drop versus temperature of the target MOSFET device under a reference current, wherein the reference current is much smaller than the test current during the test; The test circuit is used to perform the test, and during the test, the reference current is reversely injected into the target MOSFET device to obtain the real-time tube voltage drop of the target MOSFET device under the test, and the junction temperature of the target MOSFET device is determined according to the tube voltage drop versus temperature curve of the target MOSFET device.

2. The method for determining junction temperature of a MOSFET device dynamic test according to claim 1, characterized in that: The reference current is at mA level and does not exceed 10 mA.

3. The method for determining junction temperature of a MOSFET device dynamic test according to claim 1, characterized in that: A reference current is injected into the MOSFET device at different temperatures, and a corresponding tube voltage drop is obtained to fit a tube voltage drop versus temperature curve of the target MOSFET device.

4. The method for determining junction temperature of a MOSFET device dynamic test according to claim 3, characterized in that: The target MOSFET device is heated / cooled at a uniform rate so that the target MOSFET device is at different temperatures.

5. The method for determining junction temperature of a MOSFET device dynamic test according to claim 1, characterized in that: After the test circuit is constructed, a power supply circuit for providing the reference current is connected to the test circuit, and the reference current is opposite to the test current generated when the test circuit performs a test.

6. The method for determining junction temperature of a MOSFET device dynamic test according to claim 1 or 5, characterized in that: When no test is performed, a tube voltage drop versus temperature curve of the target MOSFET device is fitted offline.

7. A circuit for dynamic testing of MOSFET devices, characterized in that: including a test circuit for performing a target MOSFET device test and a power supply circuit for providing a reference current; The test circuit includes a power supply terminal and a target MOSFET device and an auxiliary MOSFET device connected in series; The target MOSFET device and the auxiliary MOSFET device are cooperatively turned off to perform a dynamic test; The power supply circuit is connected to the target MOSFET device to provide a reference current to the target MOSFET device; and further comprises: executing a junction temperature determination method for a dynamic test of a MOSFET device according to any one of claims 1 to 6 to obtain a junction temperature of the target MOSFET device.

8. The circuit for dynamic testing of MOSFET devices according to claim 7, characterized in that: The test circuit also includes an inductor connected in parallel with the auxiliary MOSFET device.

9. The circuit for dynamic testing of MOSFET devices according to claim 7, characterized in that: The test circuit also includes a collection device for collecting the tube voltage drop of the target MOSFET device.

10. A test unit, characterized in that: The MOSFET device dynamic test circuit comprises the MOSFET device dynamic test circuit as described in any one of claims 7 to 9, and is used for short circuit test and / or double pulse test of the MOSFET device.

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