Digital multimeter with IGBT test

Abstract

The application relates to the field of electronic measurement, and discloses a digital multimeter with IGBT testing. In the application, a power supply module, a signal generation and sampling module, a core processing and display module, and a test interface and function support assembly are integrated, so that the basic measurement function of a traditional multimeter / megohmmeter is retained, and IGBT testing capability is additionally added. Specifically, a transformer in the test interface and function support assembly can output a voltage meeting the IGBT testing requirement, and in cooperation with red and black test probes directly contacting a C pole, an E pole and a G pole of the IGBT, the on or off state of the IGBT can be quickly judged; and the signal generation and sampling module combines a high-frequency signal output end of an MCU with a battery voltage to form a stable 30V direct-current signal at the end of the red test probe, and then the signal is divided by the measured material and sampled and processed by the MCU, so that the device can measure conventional resistance, voltage and other parameters and can also detect the performance of the IGBT and other semiconductor elements, and the application scenarios of the instrument are significantly widened.

Description

Technical Field

[0001] This application belongs to the field of electronic measurement technology, specifically a digital multimeter with IGBT testing capability. Background Technology

[0002] A digital multimeter is an electronic measuring instrument widely used in electronic engineering, power maintenance, home appliance testing, and scientific research. It measures basic electrical parameters such as voltage, current, and resistance, and also has functions including measuring capacitance, frequency, temperature, diode continuity, and circuit continuity testing. Its core principle is to convert analog signals into digital signals using a built-in analog-to-digital converter (ADC), displaying the measurement results digitally on an LCD screen. Compared to traditional pointer multimeters, it offers advantages such as higher accuracy, easier reading, faster response, and stronger anti-interference capabilities. Modern digital multimeters typically feature intelligent functions such as automatic range selection, data hold, low battery warning, and overload protection. Some high-end models also support true RMS measurement, waveform analysis, and data storage. Its structure generally includes a display screen, function knobs, test jacks, and test leads. Simple to operate and portable, it is an indispensable tool for electronics technicians and hobbyists.

[0003] However, existing digital multimeters are insufficient to test the continuity or functionality of IGBTs because their diode range voltage is too low. Utility Model Content

[0004] The purpose of this application is to provide a digital multimeter with IGBT testing capability in order to solve the problems mentioned above.

[0005] The technical solution adopted in this application is as follows: A digital multimeter with IGBT testing, comprising: a power module, a signal generation and sampling module, a core processing and display module, and a test interface and function support components;

[0006] The power module internally includes a battery, filter capacitors C1, C2, C3, C4, C5, C6 and C7; a voltage regulator module U2 and a discharge resistor R1;

[0007] The signal generation and sampling module is internally equipped with an MCU high-frequency signal output terminal, a capacitor, diodes D2 and D3, a red probe terminal, the material under test, a resistor, and an MCU signal sampling terminal.

[0008] The core processing and display module internally includes an MCU and an LCD display screen. The MCU, as the core processing unit, integrates signal amplification circuitry and AC-DC conversion circuitry.

[0009] The test interface and function support components are internally equipped with a transformer and test leads.

[0010] In a preferred embodiment, the battery output terminal of the power module is connected to the input terminals of C1 and C2, the output terminals of C1 and C2 are connected to the input terminal of U2, the output terminal of U2 is connected to the input terminals of C3 and C4, and the output terminals of C3 and C4 are connected to the power input terminal of the MCU; one end of R1 is connected to the power terminal of the MCU, and the other end is grounded.

[0011] In a preferred embodiment, pin 93 of the MCU of the signal generation and sampling module is connected to the input terminals of C5, C6, C7, D2, and D3. The output terminals of C5, C6, C7, D2, and D3, along with the battery voltage, are connected to the red probe terminal via D2. The red probe terminal is connected to the input terminals of R2 and R3 after passing through the material being measured. The output terminals of R2 and R3 are connected to pin 2 of the MCU.

[0012] In a preferred embodiment, the output of the MCU of the core processing and display module is connected to the input of the LCD.

[0013] In a preferred embodiment, the test interface is connected to the output terminal of the transformer of the functional support component with red and black probes for contacting the collector (C), emitter (E), and collector (G) terminals of the IGBT.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of this application are:

[0015] 1. In this application, by integrating a power supply module, a signal generation and sampling module, a core processing and display module, and test interface and function support components, not only are the basic measurement functions of a traditional multimeter / megohmmeter retained, but IGBT testing capabilities are also added. Specifically, the transformer in the test interface and function support components can output a voltage that meets the IGBT testing requirements. Combined with the red and black probes directly contacting the IGBT's collector (C), emitter (E), and gate (G) terminals, its conduction or closed state can be quickly determined. The signal generation and sampling module combines the MCU's high-frequency signal output with the battery voltage to form a stable 30V DC signal at the red probe. This signal is then divided by the tested material and sampled by the MCU. This design allows the device to measure both conventional parameters such as resistance and voltage, and to specifically test the performance of semiconductor components like IGBTs, significantly broadening the instrument's applicable scenarios.

[0016] 2. In this application, the power module is powered by a battery, and after multi-stage filtering and U2 voltage regulation, it outputs a stable 3.6V voltage to power the MCU. The setting of the R1 discharge resistor avoids residual power after power-off, ensuring the stable operation of the core processing module from the power supply end. The MCU in the core processing module integrates signal amplification and AC-DC conversion circuits, which can accurately amplify and convert the sampled signal, and directly present the test results with the LCD display, reducing the need for manual calculation or external equipment analysis. At the same time, the test signal generation and sampling process is compactly designed, and the probe contact test method does not require complicated wiring, making the operation simple and efficient, which not only lowers the testing threshold but also improves the testing efficiency. Attached Figure Description

[0017] Figure 1 This is a block diagram of the overall structure of this application;

[0018] Figure 2 This is a schematic diagram of the circuit principle in this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] Example:

[0021] Reference Figure 1-2 A digital multimeter with IGBT testing capabilities includes: a power module, a signal generation and sampling module, a core processing and display module, and test interface and function support components.

[0022] The power module internally includes a battery, filter capacitors C1, C2, C3, C4, C5, C6 and C7; a voltage regulator module U2 and a discharge resistor R1;

[0023] The signal generation and sampling module is internally equipped with an MCU high-frequency signal output terminal, capacitors, diodes D2 and D3, red probe terminals, the material being measured, resistors, and an MCU signal sampling terminal.

[0024] The core processing and display module internally houses an MCU and an LCD display. The MCU, as the core processing unit, integrates signal amplification circuitry and AC-DC conversion circuitry.

[0025] The test interface and functional support components are internally equipped with transformers and test leads.

[0026] The power module internally includes a battery, filter capacitors, a voltage regulator module, and a discharge resistor. The battery serves as the power source, and its output voltage is first filtered by capacitors C1 and C2. The filtered voltage is then input to the U2 voltage regulator module, where it is further regulated. Finally, it is further stabilized by capacitors C3 and C4, ultimately outputting a stable 3.6V voltage to power the MCU. R1 acts as a discharge resistor, connected between the MCU power supply and ground. This discharge resistor quickly releases residual power from the MCU after power-off, enabling rapid device shutdown.

[0027] The signal generation and sampling module internally includes an MCU high-frequency signal output terminal, capacitors, diodes, a red probe, the material being measured, resistors, and an MCU signal sampling terminal. Specifically, pin 93 of the MCU serves as the high-frequency signal output terminal. The generated high-frequency electrical signal is transmitted sequentially through three capacitors C5, C6, and C7, and two diodes D2 and D3. Simultaneously, the battery voltage is also combined with the aforementioned high-frequency signal through D2, ultimately forming a DC voltage signal of approximately 30V at the red probe terminal. When the red probe touches the material being measured, this voltage signal is divided by the material. The divided signal is then transmitted through two resistors, R2 and R3, to pin 2 of the MCU, where the signal sampling is completed.

[0028] The core processing and display module internally houses an MCU and an LCD display. The MCU, as the core processing unit, integrates signal amplification and AC-DC conversion circuits. It amplifies the measurement signal input from the signal sampling terminal (pin 2) and converts the AC signal into a recognizable numerical signal. The converted numerical signal is output by the MCU to the LCD display, which visually presents the measurement results of the measured material and information such as the IGBT on-state voltage.

[0029] The test interface and function support components are internally equipped with a transformer and test leads. The transformer integrated inside the instrument can output a voltage that meets the testing requirements of IGBTs, specifically supporting continuity or closure tests between the collector (C), emitter (E), and gate (G) terminals of the IGBT, thereby determining the quality of the IGBT. The red and black test leads serve as the test interface, directly contacting the material under test or the electrodes of the IGBT, and working in conjunction with the voltage output from the transformer to complete the actual test operation.

[0030] The battery output terminal of the power module is connected to the input terminals of C1 and C2. The output terminals of C1 and C2 are connected to the input terminal of U2. The output terminal of U2 is connected to the input terminals of C3 and C4. The output terminals of C3 and C4 are connected to the power input terminal of the MCU. One end of R1 is connected to the power terminal of the MCU, and the other end is grounded.

[0031] The MCU pin 93 of the signal generation and sampling module is connected to the input terminals of C5, C6, C7, D2, and D3. The output terminals of C5, C6, C7, D2, and D3, along with the battery voltage, are connected to the red probe terminal via D2. The red probe terminal is connected to the input terminals of R2 and R3 after passing through the material being measured. The output terminals of R2 and R3 are connected to pin 2 of the MCU.

[0032] The output of the MCU in the core processing and display module is connected to the input of the LCD.

[0033] The output terminals of the transformer in the test interface and functional support components are connected to the red and black test leads to contact the collector (C), emitter (E), and gate (G) terminals of the IGBT.

[0034] The implementation principle of this embodiment of a digital multimeter with IGBT testing is as follows: the battery of the power module is filtered by C1 and C2 and then regulated by U2, and then filtered by C3 and C4 to output a stable 3.6V voltage to power the MCU. R1 is responsible for the rapid discharge of the MCU after power-off. The high-frequency electrical signal generated by pin 93 of the MCU is combined with the battery voltage through C5, C6, C7, D2, and D3 to form an approximately 30V DC voltage signal at the red probe. This signal is divided by the material being tested and transmitted to pin 2 of the MCU for sampling through R2 and R3. The MCU amplifies the sampled signal and performs AC-DC conversion before outputting the result to the LCD display. The transformer inside the instrument provides the required voltage for the conduction or closure test of the IGBT's collector, emitter, and gate terminals, and completes the testing function in conjunction with the red and black probes.

[0035] From the above, we can conclude that:

[0036] This application integrates a power module, a signal generation and sampling module, a core processing and display module, and test interfaces and function support components. It not only retains the basic measurement functions of a traditional multimeter / megohmmeter but also adds IGBT testing capabilities. Specifically, the transformer in the test interface and function support components outputs a voltage that meets the IGBT testing requirements. Combined with the red and black probes directly contacting the IGBT's collector (C), emitter (E), and gate (G) terminals, it can quickly determine its conduction or closed state. The signal generation and sampling module combines the MCU's high-frequency signal output with the battery voltage to form a stable 30V DC signal at the red probe. This signal is then divided by the tested material and sampled by the MCU. This design allows the device to measure conventional parameters such as resistance and voltage, as well as specifically test the performance of semiconductor components like IGBTs, significantly expanding the instrument's applicable scenarios. It is particularly suitable for fields requiring multi-type component testing, such as electronic repair and circuit testing.

[0037] The power module is powered by a battery. After multi-stage filtering (C1 and C2 for initial filtering, and C3 and C4 for secondary filtering) and processing by the U2 voltage regulator module, it outputs a stable 3.6V voltage to power the MCU. The setting of the R1 discharge resistor avoids residual power after power-off, ensuring the stable operation of the core processing module from the power supply end. The MCU in the core processing module integrates signal amplification and AC-DC conversion circuits, which can accurately amplify and convert the sampled signal, and directly present the test results on the LCD display, reducing the need for manual calculation or external equipment analysis. At the same time, the process of generating the test signal (the high-frequency signal is combined with the battery voltage to form a 30V DC signal) and sampling (after voltage division, it is transmitted to the MCU via R2 and R3) is compactly designed. The probe contact test method does not require complicated wiring, making the operation simple and efficient, which not only lowers the testing threshold but also improves the testing efficiency.

[0038] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A digital multimeter with IGBT test, characterized in that: include: Power supply module, signal generation and sampling module, core processing and display module, and test interface and function support components; The power module internally includes a battery, filter capacitors C1, C2, C3, C4, C5, C6 and C7; a voltage regulator module U2 and a discharge resistor R1; The signal generation and sampling module is internally equipped with an MCU high-frequency signal output terminal, a capacitor, diodes D2 and D3, a red probe terminal, the material under test, a resistor, and an MCU signal sampling terminal. The core processing and display module is equipped with an MCU and an LCD display screen. The MCU, as the core processing unit, integrates signal amplification circuit and AC-DC numerical conversion circuit. The test interface and function support components are internally equipped with a transformer and test leads.

2. A digital multimeter with IGBT test as claimed in claim 1 characterized in that: The battery output terminal of the power module is connected to the input terminals of C1 and C2. The output terminals of C1 and C2 are connected to the input terminal of U2. The output terminal of U2 is connected to the input terminals of C3 and C4. The output terminals of C3 and C4 are connected to the power input terminal of the MCU. One end of R1 is connected to the power terminal of the MCU, and the other end is grounded.

3. A digital multimeter with IGBT test as claimed in claim 1 characterized in that: The MCU pin 93 of the signal generation and sampling module is connected to the input terminals of C5, C6, C7, D2, and D3. The output terminals of C5, C6, C7, D2, and D3, along with the battery voltage, are connected to the red probe terminal via D2. The red probe terminal is connected to the input terminals of R2 and R3 after passing through the material being measured. The output terminals of R2 and R3 are connected to pin 2 of the MCU.

4. The digital multimeter with IGBT testing of claim 1, wherein: The output of the MCU in the core processing and display module is connected to the input of the LCD.

5. The digital multimeter with IGBT testing of claim 1, wherein: The test interface and the output terminal of the transformer of the functional support component are connected to the red and black probes.

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