Embedded N-MOSFET-based repeated avalanche test system

Abstract

The invention provides a repeated avalanche test system based on an embedded N-MOSFET, and the system comprises a heating module which is used for heating a to-be-tested device; the control module is used for providing a pulse signal to control the on-off of the heating module and adjust the heating temperature of the heating module; the test circuit is electrically connected with the to-be-tested device and receives the control signal provided by the control module to drive the to-be-tested device to be conducted so as to complete repeated avalanche tests; and the power supply module supplies power to the heating module, the control module and the test circuit. The system provided by the invention can meet the test requirements of different types of N-MOSFET devices, and is simple in structure and convenient to operate.

Description

Technical Field

[0001] The invention relates to the field of semiconductor device testing, and in particular to an embedded N-MOSFET repetitive avalanche testing system. Background Art

[0002] Power MOSFET is a widely used semiconductor device, often used in high-frequency switching circuits. Repetitive avalanche testing is a test method to evaluate the tolerance of power devices (such as MOSFET) under periodic pulse conditions. This test applies a periodic switching signal to the gate of the device under test, causing it to repeatedly switch, thereby periodically storing energy in the inductor and releasing the energy through device avalanche.

[0003] The energy of each avalanche is usually much smaller than the single pulse avalanche breakdown energy (EAS), but the energy accumulated over multiple repetitions will increase significantly, causing the chip junction temperature and the tube case temperature to rise. Therefore, in the repetitive avalanche test, special attention should be paid to the accumulation effect of the device's thermal stress and gate oxide traps, which may cause device degradation or failure. However, the existing repetitive avalanche test system has a relatively complex structure and cumbersome operation, which affects the user experience. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention proposes an embedded N-MOSFET repetitive avalanche test system, which mainly solves the problems of complex structure and inconvenient operation of the existing test system.

[0005] In order to achieve the above purpose and other purposes, the technical solution adopted by the present invention is as follows.

[0006] The present application provides an embedded N-MOSFET repetitive avalanche test system, comprising: a heating module, which is used to heat a device under test; a control module, which is used to provide a pulse signal to control the opening and closing of the heating module and adjust the heating temperature of the heating module; a test circuit, which is electrically connected to the device under test and receives a control signal provided by the control module to drive the device under test to be turned on to complete a repetitive avalanche test; and a power supply module, which supplies power to the heating module, the control module and the test circuit respectively.

[0007] In one embodiment of the present application, the heating module includes a heating unit and a first switch unit. When in use, the heating unit is attached to the surface of the device under test, the first switch unit is connected in series in the loop where the heating unit is located, and receives the pulse signal to switch the on / off state of the loop, so that the heating temperature of the device under test by the heating unit is maintained at a preset temperature.

[0008] In one embodiment of the present application, the system also includes a temperature detection module, which includes a detection end and a control chip. The detection end is attached to the surface of the device under test to obtain a real-time temperature signal of the device under test, and the control chip sends the real-time temperature signal to the control module, wherein the control module generates the pulse signal according to the real-time temperature signal to adjust the on / off state of the heating unit.

[0009] In one embodiment of the present application, the test circuit includes: a driving unit, which is used to convert the control signal into a high-voltage driving signal to output to the control end of the device under test; a digital variable resistor, which adjusts the resistance value between the driving unit and the control end of the device under test according to the adjustment signal of the control module; a programmable power supply, which receives the voltage adjustment signal of the control module and outputs a corresponding supply voltage; one end of the programmable power supply is connected to the positive end of the programmable power supply, and the other end is connected to the drain of the device under test, and the source of the device under test and the negative end of the programmable power supply are grounded.

[0010] In an embodiment of the present application, the variable inductor is assembled in a pluggable manner.

[0011] In one embodiment of the present application, the system also includes a data input unit, which records the expected heating temperature of the heating unit during the test, the driving resistance value of the digital variable resistor, the inductance value of the variable inductor used in the test, and the voltage value of the programmable power supply.

[0012] In one embodiment of the present application, the system further includes a display module, which is connected to the control module to display the data entered by the data input unit and the real-time collected data.

[0013] In one embodiment of the present application, the power supply module includes a main power supply unit, a first voltage regulator and a second voltage regulator; the first voltage regulator and the second voltage regulator are respectively powered by the main power supply unit, the first voltage regulator powers the control module; the second voltage regulator powers the heating module and the test circuit.

[0014] In one embodiment of the present application, the driving unit, the programmable power supply and the digital rheostat communicate with the control module via a serial communication protocol.

[0015] In one embodiment of the present application, the system further includes a test fixture, wherein the test fixture is used to clamp the device under test, and the source, drain and control terminal of the device under test are led out through the test fixture.

[0016] As described above, the embedded N-MOSFET repetitive avalanche test system proposed in the present application has the following beneficial effects.

[0017] The test system of the present application has a simple structure and is easy to operate, and can meet the test requirements of different types of devices under test. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the overall architecture of an embedded N-MOSFET repetitive avalanche test system in one embodiment of the present application.

[0019] Figure 2 It is a schematic diagram of a display interface in an embodiment of the present application.

[0020] Figure 3 This is a schematic diagram of a display interface in another embodiment of the present application. DETAILED DESCRIPTION

[0021] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0022] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0023] See also Figure 1 , Figure 1The overall architecture diagram of the embedded N-MOSFET repetitive avalanche test system in one embodiment of the present application. The embedded N-MOSFET repetitive avalanche test system in the embodiment of the present application includes a heating module, which is used to heat the device under test; a control module, which is used to provide a pulse signal to control the opening and closing of the heating module and adjust the heating temperature of the heating module; a test circuit, which is electrically connected to the device under test and receives a control signal provided by the control module to drive the device under test to conduct to complete the repetitive avalanche test; a power supply module, which supplies power to the heating module, the control module and the test circuit respectively. Specifically, the device under test here mainly refers to N-MOSFET. A special test fixture can be set up, and the N-MOSFET device is placed in the test fixture. The source, gate and drain of the N-MOSFET are led out through the test fixture, and the gate of the N-MOSFET device is used as the control terminal. Each electrode of the N-MOSFET device is connected to the test circuit respectively, and the on and off state of the N-MOSFET device is adjusted by the test circuit. At the same time, the heating module continues to heat the N-MOSFET device during the test, and the control module can control the heating time and heating temperature of the heating module through the pulse signal. The pulse signal here refers to the pulse amplitude modulation signal.

[0024] In one embodiment, the heating module includes a heating unit and a first switch unit. In the use state, the heating unit is attached to the surface of the device under test. The first switch unit is connected in series in the loop where the heating unit is located, and receives the pulse signal to switch the on / off state of the loop, so that the heating temperature of the device under test by the heating unit is maintained at a preset temperature. Specifically, the heating unit can be a ceramic heating sheet, and the first switch unit can be a transistor Q1, the source of the transistor Q1 is grounded, the drain is connected to one end of the ceramic heating sheet, and the other end of the ceramic heating sheet is connected to the power supply module. The gate of the transistor Q1 is connected to the control module, and the control module outputs a pulse signal to the gate of the transistor Q1, thereby controlling the transistor Q1 to be turned on and off periodically. In the on state, the ceramic heating sheet is powered on and generates heat to heat the device under test. By adjusting the duty cycle of the pulse signal, the heating time of the ceramic heating sheet can be adjusted, so that the heating temperature of the ceramic heating sheet is controlled at the set temperature. Of course, the heating unit is not limited to the ceramic heating sheet, and other types of heating devices can also be selected according to actual application requirements, which is not limited here. The transistor may be an NMOS transistor, a PMOS transistor, a triode or other device, and there is no limitation here.

[0025] In one embodiment, the system further includes a temperature detection module, and the temperature detection module includes a detection end and a control chip, wherein the detection end is attached to the surface of the device under test to obtain a real-time temperature signal of the device under test, and the control chip sends the real-time temperature signal to the control module, wherein the control module generates the pulse signal according to the real-time temperature signal to adjust the on / off state of the heating unit. Specifically, the detection end of the temperature detection module can use a thermocouple, which can be a K-type thermocouple or other types of thermocouples, which can be selected and adjusted according to actual application requirements, and are not limited here. The control chip of the temperature detection module can select MAX6675, or other chips can be selected according to actual application requirements.

[0026] In one embodiment, the test circuit includes: a driving unit, which is used to convert the control signal into a high-voltage driving signal to output to the control end of the device under test; a digital variable resistor, which adjusts the resistance value between the driving unit and the control end of the device under test according to the adjustment signal of the control module; a programmable power supply, which receives the voltage adjustment signal of the control module and outputs a corresponding power supply voltage; one end of which is connected to the positive end of the programmable power supply, and the other end is connected to the drain of the device under test, and the source of the device under test and the negative end of the programmable power supply are grounded. Specifically, the driving unit can adopt a TC4428 chip, which is mainly used for boosting, converting the low-voltage control signal output by the control module into a high-voltage driving signal and outputting it to the control end of the device under test. A digital variable resistor is connected in series between the output end and the control end of the device under test, and the digital variable resistor can also be powered by a power supply module, and the resistance value of the digital variable resistor can be adjusted by the control module. The TC4428 chip may include a power supply terminal, an output terminal, a control terminal and a ground terminal. The power supply terminal is connected to a power supply module. A digital variable resistor is connected in series between the output terminal and the control terminal of the device under test. The ground terminal is grounded. The control terminal of TC4428 is connected to the control module through a serial communication interface. The digital variable resistor may adopt an AD5272 digital variable resistor. The AD5272 digital variable resistor may include a power supply terminal, a signal input terminal, a control terminal, an output terminal and a ground terminal. The power supply terminal is connected to the power supply module, the signal input terminal is connected to the output terminal of the TC4428 chip, the output terminal is connected to the control terminal of the device under test, the ground terminal is grounded, and the control terminal of the AD5272 digital variable resistor is connected to the control module through a serial communication interface. Of course, the selection of specific drive units and digital variable resistors can also be determined according to actual application requirements, which is not limited here. For example, the serial communication interface can adopt I 2 C communication protocol. Of course, the communication protocol can also be selected and adjusted according to actual application requirements, and there is no restriction here.

[0027] In one embodiment, the variable inductor is assembled in a pluggable manner. Before testing, a variable inductor with a suitable inductance value can be selected for assembly or replacement as needed to meet the inductive load requirements of different devices.

[0028] In one embodiment, the system further includes a data input unit, through which the expected heating temperature of the heating unit, the driving resistance value of the digital variable resistor, the inductance value of the variable inductor used in the test, and the voltage value of the programmable power supply are recorded during the test. Specifically, the data input unit can be a 4*4 key matrix, or a touch screen or other numeric keyboard, etc., which can be selected according to actual application requirements.

[0029] In one embodiment, the system further includes a display module, which is connected to the control module to display the data entered by the data input unit and the real-time collected data. Specifically, the display module can be an OLED display screen or a liquid crystal display screen, etc. The type and size of the specific display module can be selected and adjusted according to actual application requirements and are not limited here. Figure 2 and Figure 3 , Figure 2 It is a schematic diagram of a display interface in an embodiment of the present application. Figure 3 This is a schematic diagram of a display interface in another embodiment of the present application. The keyboard and display screen realize human-computer interaction, set the test temperature, test cycle, test resistance value, and are equipped with an execution key and a status display.

[0030] In one embodiment, the power supply module includes a main power supply unit, a first voltage regulator and a second voltage regulator; the first voltage regulator and the second voltage regulator are respectively powered by the main power supply unit, the first voltage regulator supplies power to the control module; the second voltage regulator supplies power to the heating module and the test circuit. Specifically, the main power supply unit can adopt a 220V / 110V 15V switching power supply, the first voltage regulator can adopt a 12V voltage regulator, and the second voltage regulator can adopt a 5V voltage regulator. The selection of specific switching power supplies and voltage regulators can also be selected and adjusted according to actual application requirements, and there is no restriction here. The selection of switching power supplies is to reduce the size and weight of the power supply and improve work efficiency. The two-way voltage regulator is to meet the power supply requirements of different voltages, and at the same time can effectively reduce the ripple noise and interference of the switching power supply, and provide high-precision and low-noise voltage power supply and reference for the controller and heating system.

[0031] In one embodiment, the control module may be a single chip microcomputer (such as MCU) or the like.

[0032] The system working mode is: first, connect a 12V regulated power supply to the ceramic heater, and the negative pole is connected to the MCU through the Q1 switch. The microcontroller outputs a PWM waveform to control the opening and closing of Q1 to indirectly control the heating power of the ceramic heater. Set an expected temperature value and display it on the OLED screen. Use a K-type thermocouple to monitor the temperature change in real time, and then convert it into a digital quantity through MAX6675 and transmit it to the microcontroller. The microcontroller controls the duty cycle of the PWM waveform through the PID algorithm to realize the conduction of Q1 and stabilize the temperature at the threshold. In this way, a constant temperature controllable temperature test environment is provided for the N-MOSFET.

[0033] The test flow of repeated avalanche test can be expressed as follows:

[0034] Connect the ceramic heater to an external 12V voltage regulator, insert the DUT device (i.e., the device under test) into the fixture of the test circuit, fix the ceramic heater and the K-type thermocouple on the surface of the DUT device respectively, press the button to set the target temperature value (calculated according to the formula TJ=TC+PD*RJC; where TJ: channel temperature; TC: shell temperature; PD: power consumption; RJC: thermal resistance from channel to shell) and display it on the OLED display screen, press the execution button to turn on Q1 to make the ceramic heater work, and the real-time temperature data transmitted back by the K-type thermocouple is used to adjust the PWM duty cycle through the PID algorithm to control the opening and closing of Q1 to indirectly control the heating power of the ceramic heater.

[0035] The variable inductor of the embodiment of the present application is designed to be pluggable. When testing, the experimenter can choose an inductor in the range of 10uH to 1mH to connect. Before the N-MOSFET is turned on, the programmable power supply powers the N-MOSFET, usually taking: E ​​= 10% Vds. The MCU displays the input on the OLED display screen through key input, and sends data to the programmable power supply through serial communication. The programmable power supply provides a user-set voltage value for the N-MOSFET. At this time, the N-MOSFET is not turned on, and the Vds (drain-source voltage) is maintained at this voltage value. The digital variable resistor has an internal RDAC register, which determines the position of the resistance wiper. The RDAC register is used as a temporary register, allowing the resistance setting to be changed without restriction. The RDAC register can be used with I 2 C interface to program any position setting. When the desired wiper position is found, the value can be stored in a 50-TP memory register. The wiper position will always return to that position on subsequent power-ups. 2C protocol adjustment, input the set resistance value by key. The built-in timer of the microcontroller adjusts the PWM cycle to 10kHz, and the voltage is raised to 10V through the TC4428 chip. (It should be noted that the microcontroller uses two key parameters ARR and CCR when adjusting the duty cycle. The cycle used in this test is 10kHz, so the value of ARR is 10kHz. If the duty cycle is set to 50%, the value of CCR is 5kHz, and so on.) The tester presses the execution key of the test system, and the system starts testing. At this time, f=10kHz, and a pulse with a voltage of 10V is applied to the gate source Vgs of the N-MOSFET. The N-MOSFET is turned on, and current flows through the inductor, and energy storage begins. After a time Ton=D*T, the N-MOSFET begins to turn off. Since the inductor cannot change suddenly, an induced electromotive force will be generated in a short time to charge the parasitic capacitance Coss of the device under test. The transient di / dt is very large, and the induced electromotive force increases sharply, and repeated avalanche tests are started on the N-MOSFET. The experimenter calculates the time to complete the test based on the number of tests N required, using the formula T = N / f / 3600 (in hours). The current value can be obtained from the formula uL = L*di / dt, and the OLED display of the microcontroller can display the current value in real time. Finally, according to We = 1 / 2*L*I 2 The repetitive avalanche withstand can be obtained. During the entire test process, the LCD cooperates with the above units to give corresponding instructions.

[0036] The embedded N-MOSFET repetitive avalanche test system of the embodiment of the present application is mainly used to test the avalanche tolerance that the N-MOSFET device can withstand when encountering an inductive load, the inductive current cannot change suddenly, and a voltage spike is generated. The voltage and current data of different models of N-MOSFET are different. In order to reduce the loss of N-MOSFET, the required values ​​can be calculated in advance before testing.

[0037] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. An embedded N-MOSFET repetitive avalanche test system, characterized in that: include: A heating module, which is used to heat the device under test; A control module, which is used to provide a pulse signal to control the on / off of the heating module and adjust the heating temperature of the heating module; A test circuit, which is electrically connected to the device under test and receives a control signal provided by the control module to drive the device under test to conduct to complete a repeated avalanche test; A power supply module is used to supply power to the heating module, the control module and the test circuit respectively.

2. The embedded N-MOSFET repetitive avalanche test system according to claim 1, characterized in that: The heating module includes a heating unit and a first switch unit. When in use, the heating unit is attached to the surface of the device under test, the first switch unit is connected in series in the loop where the heating unit is located, and receives the pulse signal to switch the on / off state of the loop, so that the heating temperature of the device under test by the heating unit is maintained at a preset temperature.

3. The embedded N-MOSFET repetitive avalanche test system according to claim 2, characterized in that: The system also includes a temperature detection module, which includes a detection end and a control chip. The detection end is attached to the surface of the device under test to obtain a real-time temperature signal of the device under test, and the control chip sends the real-time temperature signal to the control module, wherein the control module generates the pulse signal according to the real-time temperature signal to adjust the on / off state of the heating unit.

4. The embedded N-MOSFET repetitive avalanche test system according to claim 1, characterized in that: The test circuit includes: A driving unit, used for converting the control signal into a high-voltage driving signal to output to the control terminal of the device under test; A digital rheostat, which adjusts the resistance value between the driving unit and the control terminal of the device under test according to the adjustment signal of the control module; A program-controlled power supply, which receives the voltage regulation signal of the control module and outputs a corresponding supply voltage; A variable inductor has one end connected to the positive end of the programmable power supply and the other end connected to the drain of the device under test. The source of the device under test and the negative end of the programmable power supply are grounded.

5. The embedded N-MOSFET repetitive avalanche test system according to claim 4, characterized in that: The variable inductor is assembled in a pluggable manner.

6. The embedded N-MOSFET repetitive avalanche test system according to claim 4, characterized in that: The system also includes a data input unit, which records the expected heating temperature of the heating unit during the test, the driving resistance value of the digital resistor, the inductance value of the variable inductor used in the test, and the voltage value of the programmable power supply.

7. The embedded N-MOSFET repetitive avalanche test system according to claim 6, characterized in that: The system also includes a display module, which is connected to the control module to display the data entered by the data input unit and the real-time collected data.

8. The embedded N-MOSFET repetitive avalanche test system according to claim 1, characterized in that: The power supply module includes a main power supply unit, a first voltage stabilizer and a second voltage stabilizer; the first voltage stabilizer and the second voltage stabilizer are respectively powered by the main power supply unit, the first voltage stabilizer supplies power to the control module; the second voltage stabilizer supplies power to the heating module and the test circuit.

9. The embedded N-MOSFET repetitive avalanche test system according to claim 4, characterized in that: The driving unit, the programmable power supply and the digital rheostat communicate with the control module via a serial communication protocol.

10. The embedded N-MOSFET repetitive avalanche test system according to claim 4, characterized in that: The system further comprises a test fixture, wherein the test fixture is used to clamp the device under test, and the source, drain and control terminal of the device under test are led out through the test fixture.

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