Junction temperature testing device for power MOSFET

Abstract

The utility model relates to the technical field of MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) testing, and discloses a power MOSFET junction temperature testing device which comprises a high electron mobility transistor, a driving resistor R3, a current-limiting resistor R2 and a current source Im, the other end of the driving resistor R3 is electrically connected with the grid electrode of the high electron mobility transistor; the other end of the current-limiting resistor R2 is electrically connected with a drain electrode of the high-electron-mobility transistor, a source electrode of the high-electron-mobility transistor is electrically connected with a drain electrode and a grid electrode of the power MOSFET, and the current source Im is electrically connected with the drain electrode and the source electrode of the power MOSFET and provides test current for a body diode of the power MOSFET; during actual use, the current source is used for continuously applying test current to the body diode of the power MOSFET, so that heat loss in the current switching process is avoided, and the accuracy of junction temperature measurement is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of MOSFET testing, in particular to a power MOSFET junction temperature testing device. Background Art

[0002] Power MOSFET devices are widely used in switching power supplies, communication systems, automotive electronics, consumer electronics and other fields due to their high frequency of switching on and off. During the operation of power MOSFET, a large amount of heat is often generated. If the heat cannot be effectively dissipated, the junction temperature of the device will increase, thereby reducing the reliability of the device and even damaging the device.

[0003] For power MOSFET, steady-state thermal resistance is an important parameter to measure the heat dissipation performance of power MOSFET. It indicates the temperature difference between the device junction temperature and the thermal reference point under unit power. Smaller steady-state thermal resistance means better thermal conduction efficiency, that is, the heat inside the device can be transferred to the casing and dissipated to the environment faster, thereby maintaining a lower operating temperature of the device. In the steady-state thermal resistance test of power MOSFET devices, it is relatively easy to measure the thermal reference point temperature and dissipated power, but accurate measurement of junction temperature has high requirements for current switching time. The schematic diagram of the existing junction temperature test circuit is shown in the figure below. Figure 1 As shown, the junction temperature test is achieved by switching the voltage source and the current source. However, due to the influence of current switching, the existing test structure has the problem of heat dissipation. At present, it is difficult to accurately perform steady-state resistance test on the power MOSFET. Utility Model Content

[0004] In view of the shortcomings of the background technology, the utility model provides a power MOSFET junction temperature test device, and the technical problem to be solved is that the accuracy of the steady-state resistance test of the power MOSFET is poor due to the influence of heat loss.

[0005] In order to solve the above technical problems, the utility model provides the following technical solutions: a power MOSFET junction temperature test device, comprising a high electron mobility transistor, a driving resistor R3, a current limiting resistor R2 and a current source Im;

[0006] One end of the driving resistor R3 is used to input a first operating voltage, and the other end of the driving resistor R3 is electrically connected to the gate of the high electron mobility transistor;

[0007] One end of the current limiting resistor R2 is used to input the second operating voltage, and the other end of the current limiting resistor R2 is electrically connected to the drain of the high electron mobility transistor. The source of the high electron mobility transistor is used to be electrically connected to the drain and gate of the power MOSFET respectively. The current source Im is used to be electrically connected to the drain and source of the power MOSFET, and is configured to provide a test current to the body diode of the power MOSFET.

[0008] In a certain embodiment, the utility model further includes a first power supply, which is electrically connected to one end of the driving resistor R3 to provide a first working voltage to one end of the driving resistor R3.

[0009] In a certain embodiment, the utility model further includes a second power supply, which is electrically connected to one end of the current limiting resistor R2 to provide a second operating voltage to one end of the current limiting resistor R2.

[0010] In some implementation manner, the gate of the high electron mobility transistor is further grounded via a leakage branch.

[0011] In some implementations, the leakage branch includes a resistor R1, and the gate of the high electron mobility transistor is grounded through the resistor R1.

[0012] In a certain embodiment, the utility model further includes a diode D1, wherein a cathode of the diode D1 is electrically connected to one end of the resistor R2, and an anode of the diode D2 is electrically connected to the other end of the resistor R2.

[0013] In a certain implementation manner, the utility model further includes a capacitor C1, and the cathode of the diode D1 is grounded through the capacitor C1.

[0014] In a certain implementation manner, the utility model further includes a temperature detection unit, and the temperature detection unit is used to test the shell temperature of the power MOSFET.

[0015] In a certain implementation manner, the utility model further includes a voltage detection unit, and the voltage detection unit is used to detect the forward voltage drop of the body diode of the power MOSFET.

[0016] In some implementations, the voltage detection unit is an oscilloscope.

[0017] Compared with the prior art, the utility model has the following beneficial effects: firstly, the heating current input to the power MOSFET can be quickly turned off by the high electron mobility transistor; secondly, the power MOSFET can be operated in the saturation region by electrically connecting the source of the high electron mobility transistor to the gate and drain of the power MOSFET respectively, thereby heating the power MOSFET, and no additional control voltage source is required to control the gate of the power MOSFET, thereby simplifying the test structure; finally, the test current is continuously applied to the body diode of the power MOSFET by the current source, thereby avoiding the loss of heat during the current switching process, thereby ensuring the accuracy of the junction temperature measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the existing power MOSFET junction temperature test;

[0019] Figure 2 It is a schematic diagram of the structure of the utility model in the embodiment;

[0020] Figure 3 is the forward voltage drop-temperature (V F -T j ) characteristic curve;

[0021] Figure 4 This is a comparison diagram of the current switching time between the existing switching circuit and the current switching time of the present invention. DETAILED DESCRIPTION

[0022] Now the utility model is further described in detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the utility model in a schematic manner, and therefore only show the components related to the utility model.

[0023] like Figure 2 As shown, a power MOSFET junction temperature testing device, a power MOSFET junction temperature testing device, includes a high electron mobility transistor Q2, a driving resistor R3, a current limiting resistor R2 and a current source Im;

[0024] One end of the driving resistor R3 is used to be electrically connected to the first power supply V1, and the first power supply V1 provides a first working voltage to one end of the driving resistor R3, and the other end of the driving resistor R3 is electrically connected to the gate of the high electron mobility transistor Q2;

[0025] One end of the current limiting resistor R2 is electrically connected to the second power supply VDD, and the second power supply VDD provides a second operating voltage for one end of the current limiting resistor R2. The other end of the current limiting resistor R2 is electrically connected to the drain of the high electron mobility transistor Q2. The source of the high electron mobility transistor Q2 is used to be electrically connected to the drain and gate of the power MOSFETQ1 respectively. The current source Im is used to be electrically connected to the drain and source of the power MOSFETQ1, and is configured to provide a test current to the body diode of the power MOSFETQ1.

[0026] In actual use, the second power supply VDD can provide a heating current for the power MOSFET Q1 through the current limiting resistor R2, and the size of the heating current can be set by setting the size of the current limiting resistor R2. The first power supply V1 controls the on and off of the high electron mobility transistor Q2 through the driving resistor R3. In addition, the high electron mobility transistor Q2 is a p-GaN structure.

[0027] In addition, in this embodiment, the gate of the high electron mobility transistor Q2 is also grounded through the leakage branch 1. The leakage branch 1 includes a resistor R1, and the gate of the high electron mobility transistor Q1 is grounded through the resistor R1. In actual use, the leakage branch 1 can provide a release channel for the charge stored in the gate of the high electron mobility transistor Q2.

[0028] In this embodiment, the utility model further includes a diode D1, the cathode of the diode D1 is electrically connected to one end of the resistor R2, and the anode of the diode D2 is electrically connected to the other end of the resistor R2. In actual use, the diode D1 provides a freewheeling path for the high electron mobility transistor Q2.

[0029] In this embodiment, the utility model further includes a capacitor C1, and the cathode of the diode D1 is grounded through the capacitor C1. The capacitor C1 can be a high-voltage film capacitor. In actual use, the capacitor C1 is used to store electrical energy. When the test requires a large current, the electrical energy stored in the capacitor C1 can be released to generate a large current.

[0030] In this embodiment, the utility model further includes a temperature detection unit, and the temperature detection unit is used to test the shell temperature of the power MOSFET Q1.

[0031] In this embodiment, the utility model further includes a voltage detection unit, which is used to detect the forward voltage drop of the body diode of the power MOSFET Q1. The voltage detection unit is an oscilloscope.

[0032] The test process of the utility model for power MOSFETQ1 is as follows:

[0033] In the initialization stage, the forward voltage drop of the body diode is selected as the temperature sensitive parameter, the forward voltage drop of the body diode of the power MOSFET Q1 is collected using an oscilloscope, and the shell temperature of the power MOSFET Q1 is monitored using a temperature sensor;

[0034] In the test phase, the switching state of the high electron mobility transistor Q2 is controlled to control the on-off of the heating current. When the temperature sensor reading no longer changes, the heat dissipation of the power MOSFET Q1 reaches a dynamic balance. At this time, the heating current is turned off and the data collected by the oscilloscope are read to obtain the forward voltage drop of the body diode of the power MOSFET Q1. Figure 3 By comparing the VF-Tj characteristic curves of the power MOSFET body diode measured under the same test current, the junction temperature measurement results can be obtained.

[0035] See also Figure 4 ,Compared with the existing test circuit, the junction temperature measurement result of the utility model is more accurate.

[0036] In summary, the utility model can firstly quickly shut down the heating current input to the power MOSFETQ2 through the high electron mobility transistor Q2; secondly, by electrically connecting the source of the high electron mobility transistor Q2 to the gate and drain of the power MOSFETQ1 respectively, the power MOSFETQ1T can be operated in the saturation region, thereby heating the power MOSFETQ1, and no additional control voltage source is required to control the gate of the power MOSFETQ1, thereby simplifying the test structure; finally, the test current is continuously applied to the body diode of the power MOSFETQ1 through the current source Im, thereby avoiding the loss of heat during the current switching process, thereby ensuring the accuracy of the junction temperature measurement.

[0037] The above is based on the disclosure of the utility model. Through the above description, relevant staff can make various changes and modifications without deviating from the technical concept of the utility model. The technical scope of the utility model is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A power MOSFET junction temperature test device, characterized in that: It includes a high electron mobility transistor, a driving resistor R3, a current limiting resistor R2 and a current source Im; One end of the driving resistor R3 is used to input a first operating voltage, and the other end of the driving resistor R3 is electrically connected to the gate of the high electron mobility transistor; One end of the current limiting resistor R2 is used to input the second operating voltage, and the other end of the current limiting resistor R2 is electrically connected to the drain of the high electron mobility transistor. The source of the high electron mobility transistor is used to be electrically connected to the drain and gate of the power MOSFET respectively. The current source Im is used to be electrically connected to the drain and source of the power MOSFET, and is configured to provide a test current to the body diode of the power MOSFET.

2. A power MOSFET junction temperature testing device according to claim 1, characterized in that: It also includes a first power supply, which is electrically connected to one end of the driving resistor R3 to provide a first working voltage for one end of the driving resistor R3.

3. A power MOSFET junction temperature testing device according to claim 1, characterized in that: It also includes a second power supply, which is electrically connected to one end of the current limiting resistor R2 to provide a second working voltage for the one end of the current limiting resistor R2.

4. A power MOSFET junction temperature testing device according to claim 1, characterized in that: The gate of the high electron mobility transistor is also grounded through a leakage branch.

5. A power MOSFET junction temperature testing device according to claim 4, characterized in that: The leakage branch includes a resistor R1, and the gate of the high electron mobility transistor is grounded through the resistor R1.

6. A power MOSFET junction temperature testing device according to claim 1 or 5, characterized in that: The device further comprises a diode D1 , wherein a cathode of the diode D1 is electrically connected to one end of the resistor R2 , and an anode of the diode D2 is electrically connected to the other end of the resistor R2 .

7. A power MOSFET junction temperature testing device according to claim 6, characterized in that: A capacitor C1 is further included, and the cathode of the diode D1 is grounded through the capacitor C1.

8. A power MOSFET junction temperature testing device according to claim 1, characterized in that: It also includes a temperature detection unit, which is used to test the shell temperature of the power MOSFET.

9. A power MOSFET junction temperature testing device according to claim 8, characterized in that: It also includes a voltage detection unit, which is used to detect the forward voltage drop of the body diode of the power MOSFET.

10. A power MOSFET junction temperature testing device according to claim 9, characterized in that: The voltage detection unit is an oscilloscope.

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