A circuit and system for voltage information diagnosis and self-calibration

Abstract

This application provides a circuit and system for voltage information diagnosis and self-calibration. By adding resistors R1 and R2 in series, the total cell voltage is divided, reducing the sampling point voltage Vsample to the measurement range of the analog-to-digital converter (ADC) of the microcontroller (MCU). The MCU accumulates and calculates the total voltage Vafe by sampling the voltages of each cell from the analog front-end (AFE). Based on the Vafe data from the AFE, the total cell voltage Vmcu is automatically calibrated to obtain the calibrated total cell voltage Vcalib. Simultaneously, the MCU compares the calibrated total cell voltage Vcalib with the Vafe voltage in real time to obtain the deviation value Vdiag. When the deviation value Vdiag exceeds a set threshold, fault diagnosis is triggered, indicating an abnormality in the cell voltage sampling function, and a safety protection mechanism is activated to meet functional safety requirements. This circuit, through reasonable hardware design, voltage protection, cell total voltage calibration, and fault diagnosis mechanism, not only improves the accuracy of system measurements but also achieves self-calibration and fault diagnosis, making it suitable for applications with high stability requirements.

Description

Technical Field

[0001] This application belongs to the field of battery protection technology, specifically relating to a circuit and system for voltage information diagnosis and self-calibration. Background Technology

[0002] In existing technologies, to meet functional safety requirements, the battery management system (BMS) of lithium-ion batteries needs to perform self-diagnosis of the cell voltage sampling function to promptly detect abnormalities and implement safety protection measures, preventing the BMS's voltage protection function from failing. Cell voltage sampling is typically implemented using an analog front-end (AFE) chip. To monitor and diagnose abnormalities in this sampling function, an analog front-end AFE chip is usually added to compare and differentiate between two voltage signals; alternatively, hardware circuitry is added to measure the voltage of the first cell using a microcontroller's analog-to-digital converter (ADC). Diagnosis is then performed by comparing the voltage measured by the analog front-end AFE chip with that measured by the ADC. However, adding an analog front-end AFE chip or using a microcontroller to measure the first cell voltage requires calibration, increasing production and testing costs as well as the overall hardware solution cost. Furthermore, monitoring only the first cell voltage cannot cover the diagnosis of other cell voltages. Utility Model Content

[0003] To address the shortcomings of the existing technology, this application provides a circuit and system for voltage information diagnosis and self-calibration. It diagnoses the sampling function of the analog front-end (AFE) cells by measuring the total voltage of the battery pack using the analog-to-digital converter (ADC) of a microcontroller (MCU). Furthermore, it achieves self-calibration through an internal mechanism, eliminating the need for production calibration and further improving the diagnostic accuracy of the microcontroller (MCU). This is a relatively low-cost and flexible solution.

[0004] In one aspect, this application provides a circuit for voltage information diagnosis and self-calibration, including an analog front-end (AFE), a microcontroller (MCU), and a resistor divider circuit;

[0005] The resistor voltage divider circuit includes resistors R1 and R2. The resistor voltage divider circuit divides the total cell voltage, reducing the sampling point voltage Vsample to the measurement range of the analog-to-digital converter (ADC) of the microcontroller MCU. The total cell voltage Vmcu is obtained by the microcontroller MCU based on the resistor voltage divider circuit.

[0006] The analog front-end AFE samples the cell voltage Vafe and sends it to the microcontroller MCU;

[0007] The microcontroller (MCU) automatically calibrates the total cell voltage Vmcu based on the cell voltage Vafe to obtain the calibrated total cell voltage Vcalib.

[0008] The microcontroller (MCU) performs fault diagnosis and identification based on the cell voltage Vafe and the total calibrated cell voltage Vcalib.

[0009] This application proposes a voltage information diagnosis and self-calibration circuit. The microcontroller (MCU) automatically calibrates the total cell voltage (Vmcu) based on the cell voltage Vafe acquired by the analog front-end (AFE), effectively eliminating errors and deviations in the system. A resistor divider circuit reduces the total cell voltage (Vsample) to the measurement range of the MCU's analog-to-digital converter (ADC). The analog front-end (AFE) samples the cell voltage, ensuring accurate voltage monitoring over a wide voltage range. The MCU also performs fault diagnosis and identification based on the cell voltage Vafe and the calibrated total cell voltage (Vcalib), and takes corresponding protective measures based on the diagnostic results. Due to its automatic calibration function, the circuit can automatically adjust according to changes in battery type, capacity, and operating environment.

[0010] Preferably, the voltage information diagnosis and self-calibration circuit proposed in this application includes:

[0011] The resistors R1 and R2 are connected in series, and an NMOS transistor Q3 is connected in the middle.

[0012] The resistor R1 is connected to the positive terminal B+ of the battery cell;

[0013] The resistor R2 is connected to the negative terminal B- of the battery cell;

[0014] The negative terminal B- of the battery cell is also connected to the ground terminal.

[0015] Preferably, the voltage information diagnosis and self-calibration circuit further includes:

[0016] The drain of the NMOS transistor Q3 is connected to the other end of the resistor R1;

[0017] The source (S) terminal of the NMOS transistor Q3 is connected to the other end of the resistor R2;

[0018] The gate (G) of the NMOS transistor Q3 is connected to one end of the microcontroller (MCU).

[0019] Preferably, the voltage information diagnosis and self-calibration circuit further includes:

[0020] The analog-to-digital converter (ADC) is connected to the source (S) terminal of the NMOS transistor Q3;

[0021] The other end of the microcontroller MCU is also connected to the negative terminal B- of the battery cell.

[0022] The voltage information diagnosis and self-calibration circuit proposed in this application controls the switching state of NMOS transistor Q3 through a microcontroller (MCU), thereby controlling the operating state of the resistor voltage divider circuit and optimizing the input voltage range of the analog-to-digital converter (ADC). The series voltage divider formed by resistors R1 and R2 and NMOS transistor Q3 is used to stabilize the voltage and input it to the ADC for sampling. Simultaneously, the precise voltage divider design of NMOS transistor Q3 improves the suppression of voltage fluctuations and noise. The MCU, combined with the cell voltage Vafe and the total calibrated cell voltage Vcalib, enables precise adjustment of the cell voltage measurement and improves the overall measurement accuracy of the circuit.

[0023] Preferably, the voltage information diagnosis and self-calibration circuit proposed in this application includes:

[0024] The microcontroller MCU outputs a high level to turn on the NMOS transistor Q3, and the analog-to-digital converter ADC acquires the sampling point voltage Vsample;

[0025] The microcontroller (MCU) outputs a low level to turn off the NMOS transistor Q3, and the analog-to-digital converter (ADC) stops acquiring the sampling point voltage Vsample.

[0026] Preferably, the voltage information diagnosis and self-calibration circuit proposed in this application further includes:

[0027] When the total voltage disturbance or the voltage becomes abnormally high, if the theoretical value of the sampling point voltage Vsample exceeds the microcontroller MCU voltage threshold, the NMOS transistor Q3 will automatically clamp and control the sampling point voltage Vsample to be within the microcontroller MCU voltage threshold.

[0028] Preferably, the voltage information diagnosis and self-calibration circuit proposed in this application further includes:

[0029] The microcontroller (MCU) automatically calibrates the total cell voltage (Vmcu) based on the cell voltage (Vafe), and obtains the calibrated total cell voltage (Vcalib) using single-point calibration or two-point calibration.

[0030] Preferably, the voltage information diagnosis and self-calibration circuit proposed in this application further includes:

[0031] The microcontroller (MCU) compares and calibrates the total cell voltage Vcalib and the cell voltage Vafe in real time to obtain the deviation value Vdiag.

[0032] When Vdiag exceeds a set threshold, a fault diagnosis and identification is triggered, indicating that the cell voltage sampling function is abnormal and a safety protection mechanism is activated.

[0033] The microcontroller (MCU) controls the switching state of the NMOS transistor Q3 by outputting a high or low level, thereby controlling the acquisition of the voltage sampling point Vsample. The MCU's control of the NMOS transistor Q3 ensures that the analog-to-digital converter (ADC) samples the voltage sampling point Vsample only when needed, avoiding unnecessary ADC conversions and effectively reducing power consumption. When the theoretical value of the sampling point voltage Vsample exceeds the MCU's voltage threshold, the NMOS transistor Q3 can automatically clamp, thus keeping the sampling point voltage Vsample within the MCU's voltage threshold.

[0034] Simultaneously, the microcontroller (MCU) compares the calibrated total cell voltage Vcalib and cell voltage Vafe in real time to obtain the deviation value Vdiag. When the deviation value Vdiag exceeds a set threshold, the system can trigger fault diagnosis and identify abnormalities in the cell voltage sampling function, thereby entering the safety protection mechanism.

[0035] Second, a system comprising: the voltage information diagnostic and self-calibration circuit described in the first aspect.

[0036] The voltage information diagnostic and self-calibration circuit proposed in this application provides accurate voltage monitoring and an efficient protection mechanism through advanced technologies such as automatic calibration, voltage clamping, and real-time fault diagnosis. Its low power consumption, simplified design, and high reliability make it suitable for various battery management and voltage monitoring applications, offering significant advantages in situations requiring long-term operation and extremely high stability.

[0037] Compared with the prior art, the advantages of this application are as follows:

[0038] 1. Self-calibration of cell total voltage (Vmcu): During the production process, the microcontroller (MCU) automatically calibrates the cell total voltage (Vmcu) based on the cell voltage (Vafe). This eliminates the need for external equipment to measure the voltage and perform calibration, improving production efficiency and reducing the risk of calibration defects.

[0039] 2. Improve the data consistency between the calibrated total cell voltage (Vcalib) and the cell voltage (Vafe) in diagnostic information, thereby enhancing the diagnostic effectiveness of cell voltage information faults. Because the calibrated total cell voltage (Vcalib) is based on the cell voltage (Vafe) during the manufacturing process, it eliminates device measurement errors between the two. For example, if the cell voltage (Vafe) measured by the analog front-end AFE is biased upwards by 50mV due to measurement device error, then the calibrated total cell voltage (Vcalib), also calibrated based on the cell voltage (Vafe), will also be biased upwards by 50mV. Voltage diagnostics compares the difference between the two, thus eliminating the 50mV upward bias error.

[0040] 3. The method compares and judges the voltage of all battery cells while offering a low-cost advantage. The cell voltage sampling function provides more comprehensive diagnostic coverage than methods that only compare the voltage of the first cell. Furthermore, self-calibration ensures the consistency of diagnostic data, allowing for reliable and effective voltage information fault diagnosis using a smaller data deviation value (Vdiag). Attached Figure Description

[0041] Figure 1 This is a circuit diagram of voltage information diagnosis and self-calibration in one embodiment of this application.

[0042] Figure 2 This is a circuit diagram of voltage information diagnosis and self-calibration in one embodiment of this application. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0044] Example 1, as Figure 1 As shown, this application provides a circuit for voltage information diagnosis and self-calibration, including an analog front-end (AFE), a microcontroller (MCU), and a resistor divider circuit;

[0045] The resistor voltage divider circuit includes resistors R1 and R2. The resistor voltage divider circuit divides the total cell voltage, reducing the sampling point voltage Vsample to the measurement range of the analog-to-digital converter (ADC) of the microcontroller MCU. The total cell voltage Vmcu is obtained by the microcontroller MCU based on the resistor voltage divider circuit.

[0046] The analog front-end AFE samples the cell voltage Vafe and sends it to the microcontroller MCU;

[0047] The microcontroller (MCU) automatically calibrates the total cell voltage Vmcu based on the cell voltage Vafe to obtain the calibrated total cell voltage Vcalib.

[0048] The microcontroller (MCU) performs fault diagnosis and identification based on the cell voltage Vafe and the total calibrated cell voltage Vcalib.

[0049] This application proposes a voltage information diagnosis and self-calibration circuit that uses resistors R1 and R2 to divide the total cell voltage, reducing the sampling point voltage Vsample to within the measurement range of the microcontroller's analog-to-digital converter (ADC). This ensures that the cell voltage can be accurately sampled and converted into a digital signal for processing. The analog front-end (AFE) accurately samples the cell voltage Vafe and transmits this data to the microcontroller (MCU), ensuring real-time monitoring of the cell voltage. Based on the cell voltage Vafe acquired by the analog front-end (AFE), the microcontroller (MCU) automatically calibrates the total cell voltage Vmcu, thereby obtaining the calibrated total cell voltage Vcalib. By comparing the cell voltage Vafe and the calibrated total cell voltage Vcalib, changes in the cell voltage are monitored in real time. This triggers fault diagnosis, promptly entering a safety protection state when the voltage sampling function malfunctions, preventing damage to subsequent processing circuits or equipment caused by incorrect or unstable voltage measurements.

[0050] This circuit design is suitable for various types of battery management systems, including lithium-ion, lead-acid, and other battery types. It has broad application prospects in electric vehicles, energy storage systems, mobile devices, and many other fields.

[0051] Preferred, such as Figure 2 As shown, the voltage information diagnosis and self-calibration circuit proposed in this application includes:

[0052] The resistors R1 and R2 are connected in series, and an NMOS transistor Q3 is connected in the middle.

[0053] The resistor R1 is connected to the positive terminal B+ of the battery cell;

[0054] The resistor R2 is connected to the negative terminal B- of the battery cell;

[0055] The negative terminal B- of the battery cell is also connected to the ground terminal.

[0056] Preferably, the voltage information diagnosis and self-calibration circuit further includes:

[0057] The drain of the NMOS transistor Q3 is connected to the other end of the resistor R1;

[0058] The source (S) terminal of the NMOS transistor Q3 is connected to the other end of the resistor R2;

[0059] The gate (G) of the NMOS transistor Q3 is connected to one end of the microcontroller (MCU).

[0060] Preferably, the voltage information diagnosis and self-calibration circuit further includes:

[0061] The analog-to-digital converter (ADC) is connected to the source (S) terminal of the NMOS transistor Q3;

[0062] The other end of the microcontroller MCU is also connected to the negative terminal B- of the battery cell.

[0063] The voltage information diagnosis and self-calibration circuit proposed in this application integrates voltage division, voltage sampling, automatic calibration, and fault diagnosis functions, improving voltage measurement accuracy, system stability, and cell protection capabilities. Simultaneously, this integration method reduces the number of circuit components and the complexity of external circuitry, lowering design difficulty and cost.

[0064] The dynamic adjustment control of NMOS transistor Q3 makes voltage sampling more flexible and accurate, further enhancing the circuit's adaptability. Automated calibration and fault diagnosis functions effectively reduce the need for manual maintenance, improving the system's intelligence and reliability.

[0065] Preferably, the voltage information diagnosis and self-calibration circuit proposed in this application includes:

[0066] The microcontroller MCU outputs a high level to turn on the NMOS transistor Q3, and the analog-to-digital converter ADC acquires the sampling point voltage Vsample;

[0067] The microcontroller (MCU) outputs a low level to turn off the NMOS transistor Q3, and the analog-to-digital converter (ADC) stops acquiring the sampling point voltage Vsample.

[0068] Preferably, the voltage information diagnosis and self-calibration circuit proposed in this application further includes:

[0069] When the total voltage disturbance or the voltage becomes abnormally high, if the theoretical value of the sampling point voltage Vsample exceeds the microcontroller MCU voltage threshold, the NMOS transistor Q3 will automatically clamp and control the sampling point voltage Vsample to be within the microcontroller MCU voltage threshold.

[0070] Preferably, the voltage information diagnosis and self-calibration circuit proposed in this application further includes:

[0071] The microcontroller (MCU) automatically calibrates the total cell voltage (Vmcu) based on the cell voltage (Vafe), and obtains the calibrated total cell voltage (Vcalib) using single-point calibration or two-point calibration.

[0072] Preferably, the voltage information diagnosis and self-calibration circuit proposed in this application further includes:

[0073] The microcontroller (MCU) compares and calibrates the total cell voltage Vcalib and the cell voltage Vafe in real time to obtain the deviation value Vdiag.

[0074] When the deviation value Vdiag exceeds the set threshold, fault diagnosis and identification are triggered, the cell voltage sampling function is determined to be abnormal, and the safety protection mechanism is activated.

[0075] The voltage information diagnosis and self-calibration circuit proposed in this application uses a microcontroller (MCU) to control the switching of an NMOS transistor Q3, precisely controlling the analog-to-digital converter (ADC) to acquire the sampling point voltage Vsample, avoiding unnecessary power consumption and noise interference. Then, automatic calibration is performed based on the cell voltage Vafe to calibrate the total cell voltage Vmcu, obtaining the calibrated total cell voltage Vcalib. Single-point or two-point calibration is employed to accurately adjust the system's voltage measurement, reducing voltage deviations caused by external disturbances or aging, and improving system stability.

[0076] Simultaneously, the microcontroller (MCU) compares the calibrated total cell voltage Vcalib and cell voltage Vafe in real time to obtain the deviation value Vdiag. When the deviation value Vdiag exceeds a set threshold, the system can trigger fault diagnosis and identify abnormalities in the cell voltage sampling function, thereby entering the safety protection mechanism to ensure that the cell is not affected by dangerous voltage and reduce the probability of failure.

[0077] Example 2: A system comprising: a voltage information diagnosis and self-calibration circuit as described in any of Examples 1.

[0078] The voltage information diagnostic and self-calibration circuit proposed in this application effectively improves the accuracy of voltage measurement and the stability of the system through mechanisms such as automatic calibration, voltage clamping, and fault diagnosis. It also enhances the circuit's adaptability and intelligence, reduces power consumption, simplifies design, and improves the safety and reliability of the battery management system. This makes it suitable for various battery management and voltage monitoring applications, as well as for long-term operation requiring extremely high stability. It offers significant advantages in battery management, energy storage, and other voltage monitoring applications.

[0079] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0080] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0081] Although the description of this application has been given in conjunction with the specific embodiments described above, it will be apparent to those skilled in the art that many substitutions, modifications, and variations can be made based on the foregoing. Therefore, all such substitutions, modifications, and variations are included within the spirit and scope of the appended claims.

Claims

1. A circuit for voltage information diagnosis and self-calibration, characterized in that: This includes an analog front-end (AFE), a microcontroller (MCU), and a resistor divider circuit. The resistor voltage divider circuit includes resistors R1 and R2. The resistor voltage divider circuit divides the total cell voltage, reducing the sampling point voltage Vsample to the measurement range of the analog-to-digital converter (ADC) of the microcontroller MCU. The total cell voltage Vmcu is obtained by the microcontroller MCU based on the resistor voltage divider circuit. The analog front-end AFE samples the cell voltage Vafe and sends it to the microcontroller MCU; The microcontroller (MCU) automatically calibrates the total cell voltage Vmcu based on the cell voltage Vafe to obtain the calibrated total cell voltage Vcalib. The microcontroller (MCU) performs fault diagnosis and identification based on the cell voltage Vafe and the total calibrated cell voltage Vcalib.

2. The circuit for voltage information diagnosis and self-calibration according to claim 1, characterized in that, Also includes: The resistors R1 and R2 are connected in series, and an NMOS transistor Q3 is connected in the middle. The resistor R1 is connected to the positive terminal B+ of the battery cell; The resistor R2 is connected to the negative terminal B- of the battery cell; The negative terminal B- of the battery cell is also connected to the ground terminal.

3. The circuit for voltage information diagnosis and self-calibration according to claim 2, characterized in that, Also includes: The drain of the NMOS transistor Q3 is connected to the other end of the resistor R1; The source (S) terminal of the NMOS transistor Q3 is connected to the other end of the resistor R2; The gate (G) of the NMOS transistor Q3 is connected to one end of the microcontroller (MCU).

4. The circuit for voltage information diagnosis and self-calibration according to claim 3, characterized in that, Also includes: The analog-to-digital converter (ADC) is connected to the source (S) terminal of the NMOS transistor Q3; The other end of the microcontroller MCU is also connected to the negative terminal B- of the battery cell.

5. The circuit for voltage information diagnosis and self-calibration according to claim 4, characterized in that, Also includes: The microcontroller MCU outputs a high level to turn on the NMOS transistor Q3, and the analog-to-digital converter ADC acquires the sampling point voltage Vsample; The microcontroller (MCU) outputs a low level to turn off the NMOS transistor Q3, and the analog-to-digital converter (ADC) stops acquiring the sampling point voltage Vsample.

6. The circuit for voltage information diagnosis and self-calibration according to claim 5, characterized in that, Also includes: When the total voltage disturbance or the voltage becomes abnormally high, if the theoretical value of the sampling point voltage Vsample exceeds the microcontroller MCU voltage threshold, the NMOS transistor Q3 will automatically clamp and control the sampling point voltage Vsample to be within the microcontroller MCU voltage threshold.

7. The circuit for voltage information diagnosis and self-calibration according to claim 6, characterized in that, Also includes: The microcontroller (MCU) automatically calibrates the total cell voltage (Vmcu) based on the cell voltage (Vafe), and obtains the calibrated total cell voltage (Vcalib) using single-point calibration or two-point calibration.

8. The circuit for voltage information diagnosis and self-calibration according to claim 7, characterized in that, Also includes: The microcontroller (MCU) compares and calibrates the total cell voltage Vcalib and the cell voltage Vafe in real time to obtain the deviation value Vdiag. When the deviation value Vdiag exceeds the set threshold, fault diagnosis and identification are triggered, the cell voltage sampling function is determined to be abnormal, and the safety protection mechanism is activated.

9. A system, characterized in that: The circuit includes a voltage information diagnosis and self-calibration circuit as described in any one of claims 1-8.

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