Ground offset test circuit, method and device

Abstract

The present invention discloses a ground offset test circuit, method, and device. The ground offset test circuit includes: a single-chip microcomputer module for controlling the operation of the circuit, including generating a control signal to adjust the output of the voltage generation module and control the switching circuit; a first voltage generation circuit, namely a 1V voltage generation circuit at the Us end, including an operational amplifier U1, resistors R1 and R2, and a capacitor C1, for generating a +1V offset voltage applied between the Us positive end and AGND; a second voltage generation circuit, namely a 1V voltage generation circuit at the GND end, including an operational amplifier U2, resistors R3, R4, and R7, for generating a -1V offset voltage applied between the GND end and AGND. The present invention generates precise +1V and -1V offset voltages, respectively, by designing independent 1V voltage generation circuits at the Us end and 1V voltage generation circuits at the GND end, thereby meeting the strict requirements of the ground offset test for positive and negative offsets. Compared with the prior art, the circuit of the present invention can more accurately adjust the offset voltage, ensuring the stability of the signal reference in various test scenarios.

Description

Technical Field

[0001] The present invention relates to a ground offset test circuit, and in particular to a ground offset test circuit, method and device, belonging to the technical field of automotive electronic and electrical testing. Background Art

[0002] Ground offset is a common phenomenon in modern vehicle electronic systems. Especially in complex electrical systems, voltage differences between devices, ground impedance, and current flow can cause slight ground potential shifts, leading to unstable signal references within the circuit. To ensure the reliability of electronic devices such as vehicle controllers and sensors in various environments, the international standard ISO 16750-1 specifies ground offset testing. This test simulates the offset phenomenon caused by factors such as power system instability and ground potential differences in actual vehicle environments, thereby verifying device performance under extreme conditions.

[0003] Existing ground offset test circuits typically only offer simple offset functionality, making it difficult to provide precise positive and negative offset voltages. Circuit performance degrades significantly when handling high currents or complex offset operations. Furthermore, existing ground offset circuits lack the ability to address power device heating, overcurrent protection, and voltage switching, failing to meet the diverse requirements of 12V and 24V systems. Especially when operating with high load currents (over 6A), traditional test circuits struggle to control the temperature rise of power devices while maintaining output accuracy. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a ground offset test circuit, method and device, which solve the problem in the prior art that accurate positive and negative offset voltages cannot be achieved.

[0005] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:

[0006] The present invention provides a ground offset test circuit, which includes:

[0007] a single-chip microcomputer module for controlling the operation of the circuit, including generating control signals to adjust the output of the voltage generation module and control the switching circuit;

[0008] The first voltage generating circuit, i.e., the 1V voltage generating circuit at the Us terminal, includes an operational amplifier U1, resistors R1, R2, and a capacitor C1, and is used to generate a +1V offset voltage applied between the positive terminal of Us and AGND;

[0009] The second voltage generating circuit, i.e., the GND terminal 1V voltage generating circuit, includes an operational amplifier U2, resistors R3, R4, and R7, and is used to generate a -1V offset voltage applied between the GND terminal and AGND;

[0010] The Us-side power input module is used to provide power input to the Us-side and includes a protection circuit connected to the voltage generating circuit;

[0011] The power supply input module includes a positive power supply POW+ and a negative power supply POW-, which are used to provide positive and negative power supplies required for circuit operation and are connected to the voltage generation and amplification module;

[0012] The operational amplifier circuit and power device module, including operational amplifiers U3 and U4, resistors R5 and R8, and Darlington power output circuit, are used to further amplify the offset voltage and stabilize the high current output;

[0013] The user load module is used to receive the adjusted offset voltage to verify the performance of the device under test (DUT) under different ground offset conditions.

[0014] As a preferred technical solution of the present invention, the single chip microcomputer module (1) is used to adjust the output offset voltage of the 1V voltage generating circuit of the Us terminal and the 1V voltage generating circuit of the GND terminal through a control signal, thereby ensuring the positive and negative offset operation of the Us terminal and the GND terminal.

[0015] As a preferred technical solution of the present invention, the pin configuration of the operational amplifier U1 in the Us terminal 1V voltage generating circuit is as follows:

[0016] Pin 1 (OUT) and pin 2 (1IN-) of U1 are connected together to pin 2 of connector CN1;

[0017] Pin 3 (1IN+) of U1 is connected to pin 1 (OUT) of U2 and pin 2 of CN3 as the reference voltage input;

[0018] Pin 4 (GND) of U1 is connected to pin 1 of CN3 through capacitor C1 and then to ground.

[0019] As a preferred technical solution of the present invention,

[0020] The pin configuration of the operational amplifier U2 in the GND terminal 1V voltage generation circuit is as follows:

[0021] Pin 1 (OUT) of U2 is connected to pin 2 of CN3;

[0022] Pin 2 (1IN-) of U2 is connected to reference voltage A1 through resistor R1 and to CN5 through resistor R3. Fuse F1 is provided before CN5 to provide overcurrent protection.

[0023] Pin 3 (1IN+) of U2 is connected to the reference voltage REF+ through resistor R2, and is connected to pin 3 (1IN+) of U3 through resistors R4 and R7.

[0024] As a preferred technical solution of the present invention, the operational amplifier circuit and power device module include:

[0025] Pin 1 (OUT) of U3 is connected to pin 2 of CN6 and pin 3 (1IN+) of U4 to provide feedback for negative offset;

[0026] Pin 2 (1IN-) of U3 is connected to CN5 (previously connected to fuse F2) through resistor R9, and is connected to reference voltage A2 through resistor R11;

[0027] Pin 1 (OUT) and pin 2 (1IN-) of U4 are connected together to pin 2 of CN8.

[0028] As a preferred technical solution of the present invention, the POW+ of the power supply input module is connected to pin 8 (VCC) of U1 and pin 1 of CN1, and the POW- is connected to the GND pin (4) of U4, to ensure the stability of the positive and negative power supply of the circuit.

[0029] When the load current exceeds 6A, power devices generate significant heat. To address this issue, the present invention utilizes dual Darlington output circuits in both the positive and negative current paths to share the high current load. This, combined with a heat sink design, effectively controls the temperature rise of the power devices, keeping them within a safe range even under high load conditions. This design not only improves the circuit's heat resistance, but also extends the device's service life and enhances test reliability.

[0030] The present invention also provides a ground offset testing method, which is applied to the aforementioned ground offset testing circuit and includes the following steps:

[0031] Step S1, applying a +1V offset voltage between the Us positive terminal and AGND through a 1V voltage generating circuit at the Us terminal, and applying a -1V offset voltage between the GND terminal and AGND through a 1V voltage generating circuit at the GND terminal;

[0032] Step S2, using the operational amplifier circuit and the Darlington output circuit of the power device module to share the output current of the offset voltage, and reducing the temperature rise of the power device through the heat sink;

[0033] Step S3, dynamically switching between positive and negative offset voltages through a switching circuit to simulate different ground offset conditions;

[0034] In step S4, the output of the offset voltage is fine-tuned using PWM by the single-chip microcomputer module to achieve precise control of the positive and negative offset voltages to meet the ground offset requirements set by the user.

[0035] The present invention also provides a ground offset test device, which has the above-mentioned ground offset test circuit, and also includes a positive and negative power supply module for providing input voltage and a display module for displaying the circuit status.

[0036] The present invention has the following beneficial effects: By designing independent 1V voltage generation circuits for the Us terminal and the GND terminal, the present invention generates precise +1V and -1V offset voltages, respectively, meeting the stringent requirements of ground offset testing for positive and negative offsets. Compared to existing technologies, the present invention's circuit can more accurately adjust the offset voltage, ensuring signal reference stability in various test scenarios. It also utilizes a Darlington output circuit and effectively shares the current load through a heat sink design, addressing the heating problem of conventional circuits under high current conditions. When the load current exceeds 6A, the circuit can still maintain output accuracy while controlling the temperature rise of power devices, significantly improving the reliability of ground offset testing. By designing the POW+ and POW- terminals in the power input module, the present invention is applicable to different power systems, including 12V and 24V, meeting the testing requirements of various vehicle electronic systems, and possessing strong adaptability and wide applicability. By designing fuses (such as F1 and F2) in key circuit components (such as the 1V voltage generation circuit for the Us terminal and the 1V voltage generation circuit for the GND terminal), overcurrent protection is implemented to prevent circuit damage caused by excessive current. In addition, by switching the positive and negative offset voltages through a switching circuit, it is possible to simulate the working conditions under different ground offset conditions, providing a guarantee for the extreme condition testing of the equipment; the offset voltage is automatically controlled and precisely adjusted through the single-chip microcomputer module, and the PWM fine-tuning function is used to ensure that the output offset voltage meets the accuracy requirements. This enables the present invention to adapt to different testing needs and provide higher accuracy and reliability in ground offset testing; it is designed according to the requirements of the international standard ISO16750-1 for ground offset, and can simulate various extreme conditions caused by ground potential offset in the vehicle environment, thereby verifying the stability of electronic equipment in complex electrical environments. By verifying the working performance of the equipment under different ground offset conditions, the present invention provides a guarantee for the reliability of key equipment such as vehicle controllers and sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of the present invention;

[0038] Figure 2 is a circuit diagram of the present invention;

[0039] In the figure: 1. Microcontroller module; 2. First voltage generating circuit; 3. Second voltage generating circuit; 4. Us end power input module; 5. Power supply input module; 6. Operational amplifier circuit and power device module; 7. User load module. DETAILED DESCRIPTION

[0040] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0041] Example 1

[0042] like Figure 1-2 As shown, this embodiment provides a ground offset test circuit for applying an offset voltage between the positive terminal Us of the input voltage and the ground terminal AGND. The ground offset test circuit includes:

[0043] The single-chip microcomputer module 1 is used to control the operation of the circuit, including generating control signals to adjust the output of the voltage generation module and control the switching circuit, such as PWM output, generating 1V voltage generation control, switching circuit control, and implementing overvoltage protection. The typical implementation process is as follows:

[0044] Microcontroller module 1 first receives user-entered control parameters, such as the desired offset voltage value and offset direction. Based on these parameters, the microcontroller generates a PWM (pulse-width modulation) signal to precisely control the output offset voltages of the 1V voltage generation circuit at the US terminal (module 2) and the 1V voltage generation circuit at the GND terminal (module 3), applying +1V and -1V offset signals, respectively. The microcontroller also controls the switching circuit to achieve positive and negative conversion of the offset voltage, ensuring smooth and impact-free voltage switching between the positive US terminal and the GND terminal.

[0045] During implementation, MCU module 1 monitors the output voltage status of each module in real time and fine-tunes the output voltage by adjusting the duty cycle of the PWM signal to ensure the stability and accuracy of the offset voltage. Simultaneously, MCU module 1 dynamically adjusts the operating state of the Darlington output circuit based on the load conditions to prevent overheating of the power devices, thereby ensuring the normal operation of the ground offset test under various load conditions.

[0046] The first voltage generating circuit 2, i.e., the 1V voltage generating circuit at the Us terminal, includes an operational amplifier U1, resistors R1 and R2, and a capacitor C1. It is used to generate a +1V offset voltage, which is applied between the positive terminal of Us and AGND to simulate a positive ground offset. During operation, when the single-chip microcomputer module 1 receives an instruction requiring a positive offset, the single-chip microcomputer controls the input signal of the operational amplifier U1 to output a stable +1V offset voltage. This voltage is appropriately divided and adjusted by resistors R1 and R2, and capacitor C1 is used to filter out high-frequency noise in the voltage to ensure a smooth and stable offset voltage.

[0047] The second voltage generation circuit 3, namely the GND terminal 1V voltage generation circuit, includes an operational amplifier U2, resistors R3, R4, and R7. It is used to generate a -1V offset voltage, which is applied between the GND terminal and AGND. This circuit is used to generate a negative offset voltage of -1V and apply it between the GND terminal and AGND to simulate a reverse ground offset. When the single-chip microcomputer module 1 sends a control signal requiring a negative offset, the operational amplifier U2 receives the instruction and outputs a stable -1V offset voltage. This voltage is divided and adjusted by resistors R3 and R4, and further adjusted by resistor R7 to ensure voltage accuracy and stability. This negative offset voltage is ultimately applied between the GND terminal and AGND, thereby implementing a reverse ground offset test.

[0048] The Us-side power input module 4 is used to provide power input to the Us-side and includes a protection circuit connected to the voltage generation circuit. It is used to provide stable power input to the Us-side to ensure the reference voltage for the test. This module also incorporates overvoltage and overcurrent protection circuits. When the input voltage exceeds the safe range, the protection circuit responds quickly to prevent circuit damage. During actual operation, the Us-side power input module 4 transmits a stable voltage to the Us-side 1V voltage generation circuit and ensures that the reference voltage remains within the preset range during the offset voltage superposition process, thereby providing reliable power support for the entire ground offset test.

[0049] The power supply input module 5 includes a positive power supply POW+ and a negative power supply POW-, which are used to provide positive and negative power supplies required for circuit operation and are connected to the voltage generation and amplification module;

[0050] Operational amplifier circuit and power device module 6, including operational amplifiers U3, U4, resistors R5, R8 and Darlington power output circuit, used to further amplify the offset voltage and stabilize the high current output;

[0051] The operational amplifier circuit and power device module 6 is designed to further amplify the offset voltage signal during ground offset testing and provide a stable high-current output to meet the requirements of testing under high-current load conditions. This module primarily consists of operational amplifiers U3 and U4, resistors R5 and R8, and a Darlington power output circuit. Operational amplifiers U3 and U4 receive the offset voltage signal from the first and second voltage generation circuits and perform preliminary voltage amplification. The amplified signal is current-limited and stabilized by resistors R5 and R8, ensuring that the signal does not attenuate or distort during transmission.

[0052] The Darlington power output circuit plays a key role in current amplification in this module. A Darlington circuit is a current amplifier consisting of two transistors connected in series (in this circuit, shown by connectors CN7 and CN9). Specifically, the Darlington circuit design connects the collector of the first transistor to the base of the second transistor, allowing current to be cascaded between the two transistors. The small current from the first transistor is amplified and enters the base of the second transistor, where it is further amplified to a larger output current. This dual-transistor Darlington circuit has a high current gain, enabling higher output currents than a single transistor.

[0053] In the operational amplifier circuit and power device module 6 of the present invention, a Darlington circuit is responsible for current amplification of the offset voltage signal amplified by the operational amplifier, ensuring a stable, high-current output even under heavy loads. This configuration enables the circuit to not only output a precise offset voltage during ground offset testing but also maintain output stability even under high current demands. Furthermore, the high-gain characteristics of the Darlington circuit reduce reliance on the output capability of the operational amplifier and reduce heat generation in the power device, thereby extending the operating life of the device and improving the reliability of the overall test circuit.

[0054] The user load module 7 is used to receive the adjusted offset voltage and connect it to the user load through the output interface to verify the performance of the device under test (DUT) under different offset conditions.

[0055] Furthermore, the single chip microcomputer module 1 is used to adjust the output offset voltage of the 1V voltage generating circuit of the Us terminal and the 1V voltage generating circuit of the GND terminal through the control signal to ensure the positive and negative offset operation of the Us terminal and the GND terminal.

[0056] Specifically, the pin configuration of the operational amplifier U1 in the 1V voltage generation circuit at the Us terminal is as follows:

[0057] Pin 1 (OUT) and pin 2 (1IN-) of U1 are connected together to pin 2 of connector CN1;

[0058] Pin 3 (1IN+) of U1 is connected to pin 1 (OUT) of U2 and pin 2 of CN3 as the reference voltage input;

[0059] Pin 4 (GND) of U1 is connected to pin 1 of CN3 through capacitor C1 and then to ground.

[0060] The pin configuration of the operational amplifier U2 in the GND terminal 1V voltage generation circuit is as follows:

[0061] Pin 1 (OUT) of U2 is connected to pin 2 of CN3;

[0062] Pin 2 (1IN-) of U2 is connected to reference voltage A1 through resistor R1 and to CN5 through resistor R3. Fuse F1 is provided before CN5 to provide overcurrent protection.

[0063] Pin 3 (1IN+) of U2 is connected to the reference voltage REF+ through resistor R2, and is connected to pin 3 (1IN+) of U3 through resistors R4 and R7;

[0064] The operational amplifier circuit and power device module include:

[0065] Pin 1 (OUT) of U3 is connected to pin 2 of CN6 and pin 3 (1IN+) of U4 to provide feedback for negative offset;

[0066] Pin 2 (1IN-) of U3 is connected to CN5 (previously connected to fuse F2) through resistor R9, and is connected to reference voltage A2 through resistor R11;

[0067] Pin 1 (OUT) and pin 2 (1IN-) of U4 are connected to pin 2 of CN8;

[0068] The POW+ of the power input module is connected to pin 8 (VCC) of U1 and pin 1 of CN1, and the POW- is connected to the GND pin (4) of U4 to ensure the stability of the positive and negative power supply of the circuit.

[0069] Specifically, the Us-terminal 1V voltage generation module 2 generates a 1V bias voltage through a single-chip microcomputer and a 1V generation circuit. The ground-terminal 1V voltage generation module 3 generates a 1V bias voltage through a single-chip microcomputer and a 1V generation circuit.

[0070] The Us-end power supply 4, as a reference voltage, is directly connected to the operational amplifier circuit; the power supply input module 5, as an energy provider, is directly connected to the operational amplifier circuit;

[0071] The operational amplifier circuit and power device module 6, as shown in the figure, includes operational amplifiers U1, U2, U3, U4, resistors R1, R2, R3, R4, R5, R7, R8, R9, R10, R11 and a Darlington power output circuit, which is used to achieve a positive or negative 1V offset between the user's US voltage and the ground voltage; and provide the required maximum current of 10A.

[0072] Specifically, the present invention implements ground offset testing by designing a first voltage generating circuit and a second voltage generating circuit, making it particularly suitable for simulating ground offsets in automotive electronic systems. In automotive electrical systems, the ground potentials of different components may slightly offset due to current flow and ground impedance, and these offsets may affect the normal operation of devices such as controllers and sensors. To this end, the ground offset test circuit of the present invention simulates the positive and negative ground offsets found in actual use environments by applying a +1V offset voltage between the positive terminal of US and AGND, and a -1V offset voltage between the GND terminal and AGND.

[0073] When a ground offset test is required for an automotive electronic system, the MCU module controls the first voltage generation circuit to output a +1V offset voltage, applied between the positive terminal of US and AGND, simulating a positive offset. Simultaneously, the second voltage generation circuit outputs a -1V offset voltage, applied between the GND terminal and AGND, simulating a negative offset. This combination of positive and negative offsets accurately reproduces ground potential variations within the automotive electrical system. The offset voltage signal is further amplified by the op amp circuit and power device module 6. Leveraging the high current drive capability of the Darlington power output circuit, the offset voltage is guaranteed to be stable under high current loads, thereby verifying the operational reliability of automotive electronic equipment under various ground offset conditions.

[0074] The working principle includes:

[0075] An offset voltage is generated by a single chip microcomputer, a 1V voltage generating circuit at the Us terminal, and a 1V voltage generating circuit at the GND terminal;

[0076] Through the operational amplifier circuit, under the switching control of the single-chip microcomputer, the offset voltage of +1V or -1V is added to the positive and negative terminals of US; and the high current power output required by the device output is provided;

[0077] User voltage Us is directly connected to REF+ and REF-;

[0078] Two sets of Darlington tubes are used at the positive terminal and the ground terminal respectively, which solves the problem of overheating under high power conditions;

[0079] And the power supply voltage input is controlled by overvoltage protection.

[0080] During operation, when the single-chip microcomputer module 1 receives a command requiring a positive offset, the single-chip microcomputer generates a corresponding PWM output, causing the 1V voltage generation circuit to accurately generate a 1V voltage. The single-chip microcomputer then switches between positive and negative 1V, and then connects them to the A1 and A2 ports of the operational amplifier module. In the operational amplifier module, the formula for adding or subtracting 1V is implemented as V0 = (R3 / R1)(V REF+ -(±V A1 ));

[0081] The present invention realizes the independent adjustment of US and GND by independent control of positive and negative power supplies, especially by utilizing the design of negative power supply, so that the offset voltage can be added or subtracted under negative conditions. Figure 2 As shown in the figure, the positive terminal of the Us input voltage is connected to REF+, and the negative terminal is connected to REF-. The operational amplifier generates +1V and -1V offset voltages. Specifically, the +1V voltage at the positive terminal is applied between A1 and AGND through the operational amplifier. This independent voltage is controlled by a switching circuit to achieve positive and negative switching. The -1V voltage at the negative terminal is also applied between A2 and AGND through the operational amplifier, and the switching circuit also achieves positive and negative switching.

[0082] In this circuit, the resistance values ​​satisfy the relationship of R1=R2, R3=R4, and the output voltage is calculated by the formula V0=(R3 / R1)(V REF+ -(±V A1 )) is achieved by precisely controlling the output offset voltage through the resistance ratio relationship to ensure the accuracy and stability of the offset voltage.

[0083] The present invention takes the user's 12VDC or 24VDC US voltage as input, uses its voltage midpoint as the reference ground AGND, applies offset voltages of +1V and -1V respectively, and then outputs;

[0084] The ground offset test circuit of this invention also features overcurrent and overvoltage protection mechanisms to mitigate abnormal current and voltage fluctuations that may occur in automotive electrical systems. These features enable ground offset testing to simulate actual operating conditions, ensuring safety and stability, and effectively evaluating the performance of automotive electronic systems in complex electrical environments.

[0085] Example 2

[0086] This embodiment provides a ground offset test method, which is applied to the ground offset test circuit in Example 1 and includes the following steps:

[0087] Step S1, applying a +1V offset voltage between the Us positive terminal and AGND through a 1V voltage generating circuit at the Us terminal, and applying a -1V offset voltage between the GND terminal and AGND through a 1V voltage generating circuit at the GND terminal;

[0088] Step S2, using the operational amplifier circuit and the Darlington output circuit of the power device module to share the output current of the offset voltage, and reducing the temperature rise of the power device through the heat sink;

[0089] Step S3, dynamically switching between positive and negative offset voltages through a switching circuit to simulate different ground offset conditions;

[0090] In step S4, the output of the offset voltage is fine-tuned using PWM by the single-chip microcomputer module to achieve precise control of the positive and negative offset voltages to meet the ground offset requirements set by the user.

[0091] Example 3

[0092] This embodiment provides a ground offset test device, which has the ground offset test circuit in Example 1 and can execute the ground offset test method in Example 2, and also includes a positive and negative power supply module for providing input voltage and a display module for displaying circuit status.

[0093] The present invention utilizes independent 1V voltage generation circuits for the Us terminal and the GND terminal to generate precise +1V and -1V offset voltages, respectively, meeting the stringent requirements of ground offset testing for positive and negative offsets. Compared to existing technologies, the present invention's circuit can more precisely adjust the offset voltage, ensuring signal reference stability in various test scenarios. It also utilizes a Darlington output circuit and effectively shares the current load through a heat sink design, addressing the heating issue of conventional circuits under high current conditions. When the load current exceeds 6A, the circuit maintains output accuracy while controlling the temperature rise of power devices, significantly improving the reliability of ground offset testing. Through the POW+ and POW- design within the power input module, the present invention is applicable to both 12V and 24V power systems, meeting the testing requirements of various vehicle electronic systems and demonstrating strong adaptability and wide applicability. Fuses (such as F1 and F2) are incorporated into key circuit components (such as the 1V voltage generation circuit for the Us terminal and the 1V voltage generation circuit for the GND terminal) to provide overcurrent protection and prevent circuit damage due to excessive current. In addition, by switching the positive and negative offset voltages through a switching circuit, it is possible to simulate the working conditions under different ground offset conditions, providing a guarantee for the extreme condition testing of the equipment; the offset voltage is automatically controlled and precisely adjusted through the single-chip microcomputer module, and the PWM fine-tuning function is used to ensure that the output offset voltage meets the accuracy requirements. This enables the present invention to adapt to different testing needs and provide higher accuracy and reliability in ground offset testing; it is designed according to the requirements of the international standard ISO 16750-1 for ground offset, and can simulate various extreme conditions caused by ground potential offset in the vehicle environment, thereby verifying the stability of electronic equipment in a complex electrical environment. By verifying the working performance of the equipment under different ground offset conditions, the present invention provides a guarantee for the reliability of key equipment such as vehicle controllers and sensors.

[0094] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments and that various modifications and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such modifications and improvements are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A ground offset test circuit for applying an offset voltage between a positive terminal Us of an input voltage and a ground terminal AGND, characterized in that: The ground offset test circuit includes: A single chip microcomputer module (1) for controlling the operation of the circuit, including generating a control signal to adjust the output of the voltage generating module and control the switching circuit; A first voltage generating circuit (2), namely a 1V voltage generating circuit at the Us terminal, comprises an operational amplifier U1, resistors R1, R2 and a capacitor C1, and is used to generate a +1V offset voltage applied between the Us positive terminal and AGND; The second voltage generating circuit (3), namely the GND terminal 1V voltage generating circuit, comprises an operational amplifier U2, resistors R3, R4 and R7, and is used to generate a -1V offset voltage applied between the GND terminal and AGND; A Us-end power input module (4), used for providing power input to the Us-end, and comprising a protection circuit connected to the voltage generating circuit; A power supply input module (5), comprising a positive power supply POW+ and a negative power supply POW-, for providing positive and negative power supplies required for circuit operation, and connected to the voltage generation and amplification module; Operational amplifier circuit and power device module (6), including operational amplifiers U3, U4, resistors R5, R8 and Darlington power output circuit, for further amplifying the offset voltage and stabilizing the high current output; The user load module (7) is used to receive the adjusted offset voltage to verify the performance of the device under test (DUT) under different ground offset conditions.

2. A ground offset test circuit according to claim 1, characterized in that: The single chip computer module (1) is used to adjust the output offset voltage of the 1V voltage generating circuit of the Us terminal and the 1V voltage generating circuit of the GND terminal through a control signal, thereby ensuring the positive and negative offset operation of the Us terminal and the GND terminal.

3. The ground offset test circuit according to claim 1, wherein: The pin configuration of the operational amplifier U1 in the Us terminal 1V voltage generation circuit is as follows: Pin 1 (OUT) and pin 2 (1IN-) of U1 are connected together to pin 2 of connector CN1; Pin 3 (1IN+) of U1 is connected to pin 1 (OUT) of U2 and pin 2 of CN3 as the reference voltage input; Pin 4 (GND) of U1 is connected to pin 1 of CN3 through capacitor C1 and then to ground.

4. The ground offset test circuit according to claim 1, wherein: The pin configuration of the operational amplifier U2 in the GND terminal 1V voltage generation circuit is as follows: Pin 1 (OUT) of U2 is connected to pin 2 of CN3; Pin 2 (1IN-) of U2 is connected to reference voltage A1 through resistor R1 and to CN5 through resistor R3. A fuse F1 is provided in front of CN5 to provide overcurrent protection. Pin 3 (1IN+) of U2 is connected to the reference voltage REF+ through resistor R2, and is connected to pin 3 (1IN+) of U3 through resistors R4 and R7.

5. The ground offset test circuit according to claim 1, wherein: The operational amplifier circuit and power device module include: Pin 1 (OUT) of U3 is connected to pin 2 of CN6 and pin 3 (1IN+) of U4 to provide feedback for negative offset; Pin 2 (1IN-) of U3 is connected to CN5 (previously connected to fuse F2) through resistor R9, and is connected to reference voltage A2 through resistor R11; Pin 1 (OUT) and pin 2 (1IN-) of U4 are connected together to pin 2 of CN8.

6. The ground offset test circuit according to claim 1, wherein: The POW+ of the power supply input module is connected to pin 8 (VCC) of U1 and pin 1 of CN1, and POW- is connected to the GND pin (4) of U4 to ensure the stability of the positive and negative power supply of the circuit.

7. A ground offset test method, applied to a ground offset test circuit as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: Step S1, applying a +1V offset voltage between the Us positive terminal and AGND through a 1V voltage generating circuit at the Us terminal, and applying a -1V offset voltage between the GND terminal and AGND through a 1V voltage generating circuit at the GND terminal; Step S2, using the operational amplifier circuit and the Darlington output circuit of the power device module to share the output current of the offset voltage, and reducing the temperature rise of the power device through the heat sink; Step S3, dynamically switching between positive and negative offset voltages through a switching circuit to simulate different ground offset conditions; In step S4, the output of the offset voltage is fine-tuned using PWM by the single-chip microcomputer module to achieve precise control of the positive and negative offset voltages to meet the ground offset requirements set by the user.

8. A ground offset test device comprising a ground offset test circuit according to any one of claims 1 to 6, characterized in that: It also includes positive and negative power supply modules for providing input voltage and a display module for displaying circuit status.

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