A compensation circuit, a compensation method and a power supply board card of a precision voltage source

Abstract

The application discloses a compensation circuit, a compensation method and a power supply board card of a precision voltage source. The precision voltage source is used for outputting a set voltage to a measured device. The compensation circuit of the precision voltage source comprises a voltage acquisition unit, which is electrically connected with the measured device and is used for acquiring an actual voltage received by the measured device; and a digital compensation unit, which is connected with the precision voltage source and the voltage acquisition unit and is used for determining a set voltage of the precision voltage source after compensation according to the actual voltage, an initial value of the set voltage and a preset division formula. The precision voltage source can improve the compensation precision through the digital compensation based on the preset division formula.

Description

Technical Field

[0001] This invention relates to the field of testing technology, and in particular to a compensation circuit, compensation method, and power supply board for a precision voltage source. Background Technology

[0002] In the field of automated integrated circuit testing, especially chip testing, testing BMS (Battery Management System) chips and ADC (Analog-to-Digital Converter) chips requires automated test equipment (ATE) to provide multi-channel precision voltage sources and precision voltmeters. The accuracy of these voltage sources and voltmeters needs to reach the microvolt level. However, when the high-precision voltage output from the automated test equipment is transmitted to the pins of the chip under test, voltage loss occurs due to line impedance, parasitic capacitance, and filtering circuits. As a result, the voltage reaching the pins of the chip under test has an error at the millivolt level, which cannot meet the requirements of high-precision testing.

[0003] In related technologies, analog loop compensation or digital loop compensation methods are used to compensate the output voltage. The main principle of analog loop compensation is as follows: when using a precision voltage source, the analog loop resource in the automated testing equipment outputs a certain voltage to the pins of the chip under test, using a four-wire Kelvin connection. After the voltage source outputs, due to losses in the circuit, a voltmeter needs to measure the voltage at the pins of the chip under test. This process is repeated multiple times to continuously compensate the precision voltage source, thereby obtaining the required voltage parameters. However, the accuracy of analog loop voltage source compensation can only reach the millivolt level.

[0004] For digital loop compensation methods, the compensation principle is multiple summation compensation. Specifically, the compensation process involves first calculating the error by combining the voltage across the measured chip with the voltage output from a precision voltage source, and then applying this error to the precision voltage source. Since the output voltage changes after compensation while the overall circuit impedance remains constant, the current changes, generating new errors, necessitating a repetition of the above steps. In other words, related technologies require multiple summation calculations, which rely on factors such as the bandwidth, drift, computation and response time of the analog devices used for summation, and the signal link impedance, leading to interference and lower compensation accuracy. Summary of the Invention

[0005] This invention provides a compensation circuit, compensation method, and power supply board for a precision voltage source. By setting up a digital compensation unit, digital compensation is achieved based on a preset division formula to improve compensation accuracy.

[0006] According to one aspect of the present invention, a compensation circuit for a precision voltage source is provided, the precision voltage source being used to output a set voltage to a device under test, the compensation circuit for the precision voltage source comprising:

[0007] A voltage acquisition unit is used to be electrically connected to the device under test and to acquire the actual voltage received by the device under test;

[0008] A digital compensation unit is connected to the precision voltage source and the voltage acquisition unit. The digital compensation unit is used to determine the set voltage after compensation by the precision voltage source based on the actual voltage, the initial value of the set voltage, and a preset division formula.

[0009] Optionally, the preset division formula is:

[0010] ;

[0011] Among them, V Set_cmp The set voltage after compensation by the precision voltage source; V Set The initial value of the set voltage; V mr The actual voltage is denoted as .

[0012] Optionally, the voltage acquisition unit includes an analog-to-digital converter, which is electrically connected to the digital compensation unit. The analog-to-digital converter is used to convert the actual voltage into digital form and send it to the digital compensation unit.

[0013] The digital compensation unit is used to determine the digitally compensated set voltage based on the actual voltage in digital form, the initial value of the set voltage, and a preset division formula; and / or,

[0014] The digital compensation unit is also used to send the compensated digital form of the set voltage to the precision voltage source after calibration.

[0015] Optionally, the digital compensation unit includes a field-programmable gate array or a microcontroller.

[0016] Optionally, the voltage acquisition unit is also used to adjust the range according to the actual voltage.

[0017] According to another aspect of the present invention, a power supply board is provided, the power supply board including at least one test channel;

[0018] The test channel includes a precision voltage source and a compensation circuit for the precision voltage source as described above; the test channel also includes a high-side output, a low-side output, a high-side sensing sensor, and a low-side sensing sensor.

[0019] The first terminal of the precision voltage source is electrically connected to the high-end output, and the second terminal of the precision voltage source is electrically connected to the low-end output.

[0020] The first end of the voltage acquisition unit is electrically connected to the sensing high end, and the second end of the voltage acquisition unit is electrically connected to the sensing low end.

[0021] Optionally, the test channel further includes:

[0022] First switch, second switch, third switch, and fourth switch;

[0023] The first terminal of the precision voltage source is electrically connected to the high-end output via the first switch, and the second terminal of the precision voltage source is electrically connected to the low-end output via the second switch.

[0024] The first end of the voltage acquisition unit is electrically connected to the sensing high end through the third switch, and the second end of the voltage acquisition unit is electrically connected to the sensing low end through the fourth switch.

[0025] According to another aspect of the present invention, a compensation method for a precision voltage source is also provided, executed by a compensation circuit of the precision voltage source as described above, the precision voltage source being used to output a set voltage to the device under test, the compensation method comprising:

[0026] Collect the actual voltage received by the device under test;

[0027] The set voltage after compensation by the precision voltage source is determined based on the actual voltage, the initial value of the set voltage, and the preset division formula.

[0028] The precision voltage source is controlled to output the compensated set voltage.

[0029] Optionally, determining the set voltage after precision voltage source compensation based on the actual voltage, the initial value of the set voltage, and a preset division formula includes:

[0030] Substituting the actual voltage and the initial value of the set voltage into the preset division formula, the set voltage after compensation by the precision voltage source is obtained; the preset division formula is:

[0031] ;

[0032] Among them, V Set_cmp The set voltage after compensation by the precision voltage source; V Set The initial value of the set voltage; V mr The actual voltage is denoted as .

[0033] Optionally, the acquisition of the actual voltage received by the device under test includes:

[0034] The voltage acquisition unit adaptively adjusts its range and acquires the actual voltage received by the device under test;

[0035] And / or, after acquiring the actual voltage received by the device under test, the method further includes:

[0036] If the actual voltage is within the range of the voltage acquisition unit, and the difference between the actual voltage and the initial value of the set voltage is within a preset threshold, then the step of determining the set voltage after precision voltage source compensation based on the actual voltage, the initial value of the set voltage, and a preset division formula is executed.

[0037] Optionally, after acquiring the actual voltage received by the device under test, the method further includes:

[0038] Convert the actual voltage into digital form;

[0039] The step of determining the set voltage after precision voltage source compensation based on the actual voltage, the initial value of the set voltage, and a preset division formula includes:

[0040] The digitally compensated set voltage is determined based on the actual voltage in digital form, the initial value of the set voltage, and a preset division formula.

[0041] The precision voltage source includes a digital-to-analog converter;

[0042] After determining the digitally compensated set voltage based on the actual voltage in digital form, the initial value of the set voltage, and the preset division formula, the process further includes:

[0043] The compensated digital form of the set voltage is calibrated and then sent to the digital-to-analog converter.

[0044] Optionally, before acquiring the actual voltage received by the device under test, the method further includes:

[0045] Enable the calibration function of the digital-to-analog converter.

[0046] The technical solution of this invention employs a precision voltage source compensation circuit comprising a voltage acquisition unit and a digital compensation unit. The voltage acquisition unit is electrically connected to the device under test (DUT) and acquires the actual voltage received by the DUT. The digital compensation unit is connected to the precision voltage source and the voltage acquisition unit, and is used to determine the compensated set voltage based on the actual voltage, the initial value of the set voltage, and a preset division formula. Because a preset division formula is used, the compensated set voltage can be obtained with only one calculation, greatly improving the compensation speed. Furthermore, the preset division formula is implemented using digital circuitry, eliminating the need for analog components and avoiding interference from factors such as analog component drift, thus significantly improving compensation stability. In addition, since high-precision compensation of the precision voltage source can be achieved with a single compensation, the problem of low output data stability of the precision voltage source during multiple compensation processes can be avoided.

[0047] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a schematic diagram of the compensation structure of a precision voltage source in related technologies;

[0050] Figure 2 A circuit structure diagram of a compensation circuit for a precision voltage source provided in an embodiment of the present invention;

[0051] Figure 3 This is a schematic diagram of the circuit structure of a power supply board provided in an embodiment of the present invention;

[0052] Figure 4 This is a schematic diagram of a circuit structure for electrically connecting a power supply board and a chip under test, provided in an embodiment of the present invention.

[0053] Figure 5 A schematic diagram of a circuit structure for connecting a power supply board to a chip under test, provided in an embodiment of the present invention;

[0054] Figure 6 A flowchart illustrating a compensation method for a precision voltage source provided in an embodiment of the present invention;

[0055] Figure 7 A flowchart illustrating another method for compensating a precision voltage source, as provided in an embodiment of the present invention. Detailed Implementation

[0056] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0057] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0058] Before introducing the technical solution of this invention, a detailed introduction is given to the relevant technologies and existing technical problems in the field of automated testing of integrated circuits.

[0059] Figure 1 This is a schematic diagram of a compensation structure for a precision voltage source in related technologies, for reference. Figure 1 In related technologies, single-stage compensation suffers from insufficient accuracy, requiring multiple summation-based continuous compensations to achieve a certain level of precision. When testing chips, the aforementioned method suffers from voltage loss due to filtering circuits and wiring. Therefore, a voltmeter MV is needed to collect the voltage at the chip under test (the voltage after voltage source output loss), and then a multiple summation-based continuous compensation method is used to compensate to the precision voltage source FV. Specifically, this method involves summing the collected voltage of the chip under test with the output voltage of the precision voltage source FV, calculating the corresponding error, and then compensating for this error back to the precision voltage source FV before outputting. The compensation calculation process is as follows: During the first compensation... ; ; Among them, V Error V is the initial error. Set The initial set voltage for the precision voltage source FV, V measureR1 is the voltage across the chip 20 under test measured by voltmeter MV. R2 is the equivalent resistance of the trace between the high-side output FH_OUT and the chip 20 under test, and R3 is the equivalent resistance of the trace between the low-side output FL_OUT and the chip 20 under test. L Let I be the equivalent resistance of the chip 20 under test. The current in the entire circuit before compensation is I1. After the first summation compensation, the set voltage of the precision voltage source FV is compensated to: However, the output voltage changes after summation, causing a change in the current throughout the circuit. The current at this point is: Then the error becomes: The difference between the two errors is During the second compensation, the set voltage was compensated as follows: While this method of multiple summations can continuously compensate, each compensation is affected by changes in the circuit current due to variations in the precision voltage source's set voltage. This affects the circuit error and consequently, the voltage required by the chip under test. Multiple summations are needed to gradually reach the required voltage for the chip under test, and the compensation accuracy is not high, with each compensation voltage change only reaching the mV level. Furthermore, the compensation speed is slow due to the need for multiple summations. This compensation method is also limited by factors such as the bandwidth of the analog circuit, device drift, device operation and response time, and signal link impedance. These factors introduce interference, making it impossible to achieve high-precision compensation. Voltage source fluctuations also occur during the compensation process, affecting the stability of the test.

[0060] It should be noted that, Figure 1 The specific connection relationships and working principles of the sensing high-end SH_OUT, sensing low-end SL_OUT, and switches (K1~K8) shown in the diagram are well known to those skilled in the art and will not be described in detail here.

[0061] To address the aforementioned technical problems, the present invention proposes the following solutions:

[0062] Figure 2 This is a schematic diagram of the circuit structure of a compensation circuit for a precision voltage source provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the circuit structure of a power supply board provided in an embodiment of the present invention. Figure 4 This is a schematic diagram of a circuit structure for electrically connecting a power supply board and a chip under test, provided in an embodiment of the present invention. (Refer to...) Figures 2 to 4The precision voltage source compensation circuit 111 can be applied in a power supply board, which can be used to provide the required voltage to the chip under test 20. The power supply board includes at least one test channel, each test channel including the aforementioned precision voltage source 112 and the precision voltage source compensation circuit 111. The precision voltage source 112 is used to output a set voltage to the device under test (i.e., the chip under test 20). Each test channel includes a high-side output FH_OUT, a low-side output FL_OUT, a high-side sensing SH_OUT, and a low-side sensing SL_OUT. The high-side output FH_OUT is electrically connected to the first terminal of the precision voltage source 112, and the low-side output FL_OUT is electrically connected to the second terminal of the precision voltage source 112. It is understood that the potential at the first terminal of the precision voltage source 112 is higher than the potential at the second terminal of the precision voltage source 112. When testing the chip under test (DUT) 20, firstly, connect the high-side output FH_OUT and low-side output FL_OUT to the pins of the DUT 20 to be measured, respectively, and then connect the high-side sensing SH_OUT and low-side sensing SL_OUT to the pins to be measured, respectively. It should also be noted that a precision voltage source has a higher output voltage accuracy than a conventional voltage source; for example, a precision voltage source has an output voltage accuracy at the microvolt level.

[0063] The compensation circuit 111 of the precision voltage source includes a voltage acquisition unit 1111 and a digital compensation unit 1112. The voltage acquisition unit 1111 is electrically connected to the device under test (DUT) and acquires the actual voltage received by the DUT. The digital compensation unit 1112 is connected to the precision voltage source 112 and the voltage acquisition unit 1111, and is used to determine the compensated set voltage based on the actual voltage, the initial value of the set voltage, and a preset division formula.

[0064] Specifically, such as Figure 4As shown, the first terminal of the voltage acquisition unit 1111 is electrically connected to the sensing high-side SH_OUT, and the second terminal of the voltage acquisition unit 1111 is electrically connected to the sensing low-side SL_OUT. The precision voltage source 112 is used to provide a stable voltage to the chip under test 20. Due to parasitic factors and line impedance, the circuit connecting the precision voltage source 112 and the chip under test 20 cannot be equivalent to an ideal circuit in high-precision measurements, and thus has equivalent resistance. For example, the equivalent resistance between the output high-side FL_OUT and the chip under test 20 is defined as the first resistance R1, and the equivalent resistance between the output low-side FL_OUT and the chip under test 20 is defined as the second resistance R2. Assuming the voltage between the two output terminals of the precision voltage source 112 is V1 and the impedance of the chip under test 20 is RL, the current in the current loop formed by the precision voltage source 112 and the chip under test 20 is: I = V1 / (R1 + RL + R2). Then the actual voltage applied across the chip under test 20 is I * RL, which is not equal to V1, resulting in a loss of I * (R1 + R2) voltage.

[0065] In this embodiment, the voltage acquisition unit 1111 acquires the actual voltage across the chip under test 20, which is I*RL. It should be noted that the voltage acquisition unit 1111 can be a precision voltmeter, whose impedance is much greater than that of the chip under test 20. The voltage acquisition unit 1111 is essentially an open circuit for the chip under test 20, and does not draw current from it. Therefore, the acquired voltage can be considered the actual voltage applied across the chip under test 20. That is, the acquired voltage is equal to the actual voltage across the chip under test 20, with no loss.

[0066] Furthermore, after receiving the actual voltage, the digital compensation unit 1112, knowing the initial value of the set voltage of the precision voltage source and the preset division formula, can calculate the compensated set voltage of the precision voltage source using the actual voltage, the initial value of the set voltage, and the preset division formula. The preset division formula is based on the premise that the actual voltage after compensation is equal to the initial value of the set voltage before compensation. In other words, after compensating the precision voltage source, when the compensated set voltage is applied to the chip under test 20 via the circuit, the actual voltage acquired by the voltage acquisition unit 1111 should be equal to the set voltage of the precision voltage source before compensation. Furthermore, based on the principles that the current is equal everywhere in the same current loop and that the impedance of each line remains constant, the corresponding preset division formula is obtained.

[0067] It should be noted that, in this embodiment, the digital compensation unit 1112 can be a Field-Programmable Gate Array (FPGA) or a Microcontroller Unit (MCU), and no specific limitation is made here. In this embodiment, the digital compensation unit 1112 is preferably an FPGA, and FPGA-based digital compensation improves the speed of digital compensation.

[0068] Furthermore, the digital compensation unit 1112 uses digital circuitry to calculate the preset division formula, directly performing the logical calculation without the need for analog devices that perform addition or subtraction. This reduces errors caused by parameter drift and other factors associated with analog devices, resulting in higher-precision compensation down to the microvolt level. In other words, the compensation circuit of the precision voltage source in this embodiment significantly improves compensation speed and accuracy. It should be noted that in related technologies, addition operations using analog devices typically involve directly sampling voltage through a line, meaning the analog device is directly connected to the voltage acquisition unit. Analog devices are extremely sensitive to minute voltage changes, and the impedance of the line affects the accuracy of the voltage sampled by the analog device, leading to poor compensation accuracy. Moreover, since high-precision compensation of the precision voltage source can be achieved with a single compensation, the problem of unstable output data from the precision voltage source during multiple compensation processes is avoided.

[0069] Furthermore, based on a preset division formula, the set voltage after precision voltage source compensation can be obtained in a single calculation, thereby compensating for errors caused by line impedance. Compared to related technologies that involve multiple additions and summations, this method significantly improves calculation speed, which in turn greatly increases compensation speed and, consequently, testing speed.

[0070] The technical solution of this embodiment employs a precision voltage source compensation circuit comprising a voltage acquisition unit and a digital compensation unit. The voltage acquisition unit is electrically connected to the device under test (DUT) and acquires the actual voltage received by the DUT. The digital compensation unit is connected to the precision voltage source and the voltage acquisition unit, and is used to determine the compensated set voltage based on the actual voltage, the initial value of the set voltage, and a preset division formula. The preset division formula is implemented using digital circuitry, eliminating the need for analog components and avoiding interference caused by factors such as analog component drift, thus significantly improving compensation accuracy. Because of the preset division formula, the compensated set voltage can be obtained with only one calculation, greatly increasing the compensation speed; and high-precision compensation can be achieved with a single calculation, avoiding multiple acquisitions and compensation calculations, reducing data fluctuations, and improving the stability of the precision voltage source.

[0071] It should be noted that the initial value of the set voltage is the voltage that the user needs to apply to the device under test. The compensation circuit of the precision voltage source can perform multiple compensations on the precision voltage source. Each compensation is calculated using the initial value of the set voltage, and the output voltage of the precision voltage source after compensation is the compensated set voltage.

[0072] It should be noted that in this embodiment, the precision voltage source and the voltage acquisition unit are set separately, and their circuits are not connected to each other, which can reduce losses and errors.

[0073] Optionally, in some embodiments, the connection between the precision voltage source 112, the voltage acquisition unit 1111, and the chip under test 20 can employ a four-wire Kelvin method. That is, the high-side output FH_OUT is electrically connected to the first pin of the chip under test 20 via a first connection line, and the high-side sensing SH_OUT is electrically connected to the first pin of the chip under test 20 via a second connection line, with the first and second connection lines short-circuited at the first pin. The low-side output FL_OUT is electrically connected to the second pin of the chip under test 20 via a third connection line, and the low-side sensing SL_OUT is electrically connected to the second pin of the chip under test 20 via a fourth connection line, with the third and fourth connection lines short-circuited at the second pin.

[0074] Optionally, in some other embodiments, since compensation is performed using a digital compensation unit, it is only necessary to ensure that the voltage acquired by the voltage acquisition unit 1111 is the actual voltage across the chip under test 20. Whether the precision voltage source 112 directly outputs voltage to the chip under test 20 does not affect the compensation result; that is, the high-side output FH_OUT and the low-side output FL_OUT can be directly connected to the chip under test 20, or they can be coupled to the chip under test 20 through other devices. In other words, the first connection line can be electrically connected to the first pin through some structure with impedance, and the third connection line can also be electrically connected to the second pin through some structure with impedance. The connection method of the first and third connection lines is relatively flexible and can be freely connected at the position of the output lines. Of course, it is preferable that the high-side output FH_OUT and the low-side output FL_OUT are directly connected to the chip under test 20 to reduce line loss.

[0075] Optionally, the default division formula is:

[0076] (1)

[0077] Among them, V Set_cmp The set voltage after compensation by a precision voltage source; V Set To set the initial value of the voltage; V mr This is the actual voltage.

[0078] Specifically, such as Figure 4 As shown, based on the principle that the current is the same everywhere in the same current loop, the following formula can be obtained before compensating the precision voltage source:

[0079] (2)

[0080] After compensating the precision voltage source, the following formula can be obtained:

[0081] (3)

[0082] Among them, V mr1 This is the actual voltage after compensation, i.e., V. mr1 The expected value is V Set .

[0083] Therefore, we can conclude that:

[0084] (4)

[0085] By transforming equations (2) and (4) and applying the constant impedance equation, we can obtain:

[0086] (5)

[0087] Further transformation of formula (5) yields formula (1), which is the preset division formula.

[0088] Optionally, in some embodiments, the voltage acquisition unit 1111 integrates an analog-to-digital converter (ADC), which is electrically connected to the digital compensation unit. The ADC converts the actual voltage into digital form and sends it to the digital compensation unit 1112. The digital compensation unit 1112 determines the digital form of the set voltage after precision voltage source compensation based on the actual voltage in digital form, the initial value of the set voltage, and a preset division formula.

[0089] Specifically, in this embodiment, the actual voltage received by the digital compensation unit 1112 may be in the form of digital code values, and the corresponding physical value can be calculated based on the digital code values. For a precision voltage source, a digital-to-analog converter can be integrated internally. The initial input setting voltage of the precision voltage source is in digital form, which is converted into analog form by the digital-to-analog converter and then output to the chip under test. The precision voltage source needs to receive the setting voltage in digital form from the digital compensation unit. Therefore, the digital compensation unit needs to first calculate the digital code value corresponding to the setting voltage based on the analog value of the setting voltage, and then deduce the calculation formula for the analog value of the setting voltage based on the digital code value of the setting voltage. The conversion formula of the digital-to-analog converter is as follows:

[0090] (6)

[0091] Where DAcode is the digital code value corresponding to the initial value of the set voltage, V Refn The negative reference voltage, V Refp This is the positive reference voltage. It should be noted that the above conversion formula varies depending on the digital-to-analog converter, and this embodiment does not limit it.

[0092] Perform an inverse transform on the DA code to obtain V. Set The formula is:

[0093] (7)

[0094] For the voltage acquisition unit, an analog-to-digital converter (ADC) can be integrated internally to convert the acquired actual voltage into digital form. For example, taking a ±6.5V range, the ADC is an AD7175 chip, and the digital-to-analog converter (DAC) is an AD5791 chip. The conversion formula for the ADC is:

[0095] (8)

[0096] After receiving the ADcode, the digital compensation unit 1112 first converts it to calculate the analog value of the actual voltage. The conversion formula is as follows:

[0097] (9)

[0098] Where ADcode is the digital code value corresponding to the actual voltage, V Ref Here, is the reference voltage, Gain is the conversion gain, and offset is the offset value of the digital-to-analog converter. It should be noted that the above conversion formula may have different forms depending on the digital-to-analog converter, and the constants may take different values ​​depending on the situation; this embodiment does not impose any limitations on this.

[0099] The digital form of the actual voltage, the initial value of the set voltage, and the preset division formula are used to determine the digital form of the set voltage after precision voltage source compensation. That is, by substituting formulas (9) and (7) into formula (1), we can obtain:

[0100] (10)

[0101] Optionally, the digital compensation unit 1112 is also used to send the compensated digital form of the set voltage to a precision voltage source after calibration.

[0102] Specifically, V is obtained by solving formula (10). Set_cmp The set voltage is the analog value corresponding to the compensated set voltage, while the precision voltage source needs to receive the set voltage in digital form. Therefore, it can be further obtained in the digital compensation unit:

[0103] (11)

[0104] Here, SetDAcode is the digital form (digital code value) corresponding to the compensated set voltage. Further calibration of SetDAcode is performed to further improve the compensation accuracy; the calibration formula is as follows:

[0105] (12)

[0106] SetDAcode cal The digital form representing the calibrated and compensated set voltage is also the actual form that the digital compensation unit 1112 ultimately sends to the precision voltage source. The digital-to-analog converter inside the precision voltage source then converts the compensated digital set voltage into an analog voltage for output.

[0107] In this embodiment, all calculations are performed digitally. No hardware connection is required between the digital compensation unit 1112 and the precision voltage source 112, or between the digital compensation unit 1112 and the voltage acquisition unit 1111; only a communication line is needed. Therefore, interference problems caused by the impedance of hardware connections can be avoided, further improving compensation accuracy.

[0108] Optionally, the digital compensation unit 1112 includes a Field Programmable Gate Array (FPGA) or a Microcontroller Unit (MCU). The FPGA can perform parallel computation, enabling rapid calculations across multiple test channels when the power supply board includes multiple test channels. The FPGA's control speed can reach the nanosecond level, and its computation time is in the microsecond level, making it relatively fast. The MCU, on the other hand, is primarily used for serial computation.

[0109] Optionally, the voltage acquisition unit 1111 is also used to adjust the range according to the actual voltage.

[0110] Specifically, the range of the voltage acquisition unit 1111 is the range used when measuring the actual voltage. The smaller the range of the voltage acquisition unit 1111, the higher the accuracy of the actual voltage acquisition; conversely, the larger the range, the lower the accuracy. Therefore, if the acquired actual voltage is small, the range can be reduced accordingly to further improve the acquisition accuracy. Conversely, if the acquired actual voltage is large, the range can be increased accordingly to avoid failing to acquire the true actual voltage. The voltage acquisition unit 1111 can adjust its range to be the range where the maximum value acquired is greater than or equal to the currently acquired actual voltage and is closest to the actual voltage. In this embodiment, the voltage acquisition unit 1111 can adaptively adjust its range, thereby further improving the compensation accuracy of the compensation circuit.

[0111] Furthermore, it should be noted that the compensation circuit in this embodiment uses digital compensation for a single compensation, resulting in high overall compensation accuracy. In this embodiment, because a preset division digital compensation method is used, the compensation accuracy of the compensation circuit is not limited by the compensation method, but rather by the acquisition accuracy of the voltage acquisition unit 1111. Therefore, the voltage acquisition unit 1111 can use a high-precision voltmeter, achieving an acquisition accuracy at the microvolt level, and the corresponding compensation accuracy can also reach the microvolt level.

[0112] Based on the same inventive concept, this invention also provides a power supply board. For example... Figure 3 and Figure 4 As shown, the power supply board includes at least one test channel. Each test channel includes a compensation circuit 111 and a precision voltage source 112 provided in any embodiment of the present invention. The test channel includes a high-side output FH_OUT, a low-side output FL_OUT, a high-side sensing SH_OUT, and a low-side sensing SL_OUT. The number of test channels in the power supply board can be 18, but is not limited to this. The power supply board can be part of an automatic test equipment (ATE). Since the power supply board provided in the embodiments of the present invention includes the compensation circuit of the precision voltage source provided in any embodiment of the present invention, it has the same beneficial effects, which will not be repeated here.

[0113] Because the power supply board has high testing accuracy and speed, it can test BMS chips and ADC chips, among others. It exhibits high stability and minimal fluctuations during testing.

[0114] Optionally, such as Figure 5 As shown, Figure 5 This is a schematic diagram of a circuit structure for connecting a power supply board and a chip under test, provided in an embodiment of the present invention. In this embodiment, the test channel further includes: a first switch K1, a second switch K2, a third switch K3, and a fourth switch K4. The first terminal of the precision voltage source 112 is electrically connected to the high-side output FH_OUT via the first switch K1, and the second terminal of the precision voltage source 112 is electrically connected to the low-side output FL_OUT via the second switch K2. The first terminal of the voltage acquisition unit 1111 is electrically connected to the high-side sensing SH_OUT via the third switch K3, and the second terminal of the voltage acquisition unit 1111 is electrically connected to the low-side sensing SL_OUT via the fourth switch K4.

[0115] Specifically, the aforementioned switches can isolate the connection between the port of the precision voltage source and the port of the power supply board, or isolate the connection between the port of the voltage acquisition unit and the port of the power supply board. Before connecting the chip under test 20 to the power supply board, all switches should be turned off to prevent damage to the chip under test 20, the precision voltage source 112, or the voltage acquisition unit 1111 caused by unstable contact impedance or other factors during the connection process. Once the chip under test 20 is connected to the power supply board and testing of the chip under test 20 is required, the aforementioned switches should be turned off.

[0116] Alternatively, in some embodiments, the first switch K1 may be a relay.

[0117] Alternatively, in some implementations, the second switch K2 may be a relay.

[0118] Alternatively, in some implementations, the third switch K3 may be a relay.

[0119] Alternatively, in some implementations, the fourth switch K4 may be a relay.

[0120] Optionally, such as Figure 4 and Figure 5 As shown, when testing the chip under test (DUT) 20 using a power supply board, the power supply board and the DUT 20 can also be connected via switches. For example, the high-side output FH_OUT is connected to the first pin via the fifth switch K5. The low-side output FL_OUT is connected to the second pin via the sixth switch K6. The high-side sensing SH_OUT is connected to the first pin via the seventh switch K7. The low-side sensing SL_OUT is connected to the second pin via the eighth switch K8. All switches are turned off before connecting the DUT 20 to the power supply board. Once the DUT 20 is connected to the power supply board and testing is required, all switches are turned off.

[0121] Alternatively, in some implementations, the fifth switch K5 may be a relay.

[0122] Alternatively, in some implementations, the sixth switch K6 may be a relay.

[0123] Alternatively, in some implementations, the seventh switch K7 may be a relay.

[0124] Alternatively, in some implementations, the eighth switch K8 may be a relay.

[0125] Optionally, in some implementations, the voltage acquisition unit in the power supply board can be equipped with a corresponding relay switch, and the corresponding voltage acquisition unit can work when the relay switch is turned on.

[0126] Optionally, in some implementations, the precision voltage source in the power supply board can be equipped with a corresponding relay switch, and the corresponding precision voltage source can work when the relay switch is turned on.

[0127] Based on the same inventive concept, this invention also provides a compensation method for a precision voltage source, which can be executed by the compensation circuit of the precision voltage source provided in any embodiment of this invention. For example... Figure 6 As shown, Figure 6 A flowchart illustrating a precision voltage source compensation method provided in an embodiment of the present invention.

[0128] Compensation methods include:

[0129] Step S110: Acquire the actual voltage received by the device under test;

[0130] Specifically, as mentioned above, when compensating for a precision voltage source, the voltage acquisition unit 1111 can first acquire the actual voltage across the device under test. This actual voltage is the voltage output by the precision voltage source after the line voltage drop.

[0131] Step S120: Determine the set voltage after precision voltage source compensation based on the actual voltage, the initial value of the set voltage, and the preset division formula.

[0132] Specifically, after receiving the actual voltage, the digital compensation unit 1112, knowing the initial value of the set voltage of the precision voltage source and the preset division formula, can calculate the compensated set voltage using the actual voltage, the initial value of the set voltage, and the preset division formula. The preset division formula is based on the premise that the actual voltage after compensation is equal to the initial value of the set voltage before compensation. In other words, after the precision voltage source is compensated, when the compensated set voltage is applied to the chip under test 20 via the circuit, the actual voltage acquired by the voltage acquisition unit 1111 should be equal to the set voltage before compensation. Furthermore, based on the principles that the current is equal everywhere in the same current loop and that the impedance of each line remains constant, the corresponding preset division formula is obtained. According to the preset division formula, the compensated set voltage can be obtained in a single calculation, thus compensating for errors caused by line impedance. Compared to related technologies that use multiple summations, this significantly improves the calculation speed, which in turn greatly increases the compensation speed and, consequently, the testing speed.

[0133] Step S130: Control the precision voltage source to output the compensated set voltage.

[0134] Specifically, after obtaining the compensated set voltage, the digital compensation unit 1112 can generate a corresponding control signal based on the compensated set voltage and send it to the precision voltage source, so that the precision voltage source outputs the compensated set voltage. When the precision voltage source outputs the compensated set voltage, the voltage applied across the device under test is closer to the initial set voltage of the precision voltage source.

[0135] The technical solution of this embodiment employs a precision voltage source compensation method that includes acquiring the actual voltage received by the device under test; determining the set voltage after precision voltage source compensation based on the actual voltage, the initial value of the set voltage, and a preset division formula; and controlling the precision voltage source to output the set voltage after compensation. Because a preset division formula is used, the set voltage after precision voltage source compensation can be obtained in only one calculation, which greatly improves the compensation speed. Furthermore, the calculation based on the preset division formula is implemented through digital circuits, eliminating the need for analog devices and avoiding interference caused by factors such as drift of analog devices, thus greatly improving the accuracy of digital compensation. Moreover, high-precision compensation can be achieved with a single calculation, avoiding multiple acquisitions and compensation calculations, reducing data fluctuations, and improving the stability of the precision voltage source.

[0136] Optionally, the set voltage after precision voltage source compensation is determined based on the actual voltage, the initial value of the set voltage, and a preset division formula, including:

[0137] Substituting the actual voltage and the initial value of the set voltage into the preset division formula, the set voltage after precision voltage source compensation is obtained; the preset division formula is: .

[0138] Among them, V Set_cmp The set voltage after compensation by a precision voltage source; V Set To set the initial value of the voltage; V mr This is the actual voltage.

[0139] Specifically, the derivation process of the preset division formula can be found in the description of the compensation circuit section of the precision voltage source in this invention, and will not be repeated here.

[0140] Optionally, acquiring the actual voltage received by the device under test (DUT) includes: the voltage acquisition unit adaptively adjusting its range and acquiring the actual voltage received by the DUT. That is, the voltage acquisition unit can adaptively adjust its acquisition range, thereby improving the accuracy of compensation. This step can be performed during actual voltage acquisition. More specifically, the voltage acquisition unit performs adaptive range adjustment within a preset time period before acquisition. Once the range adjustment is complete, the acquired voltage is taken as the actual voltage. The preset time can be determined based on actual conditions and is not limited here. The adaptive range adjustment process, for example, involves first setting an initial range for the voltage acquisition unit. If the initial range is too large compared to the acquired voltage, the range is reduced until the acquired actual voltage after range adjustment is close to the range. If the initial range is small compared to the acquired voltage, such as if the acquired voltage equals the maximum value of the current range, the range is increased, and the actual voltage is acquired again until the range is close to and greater than the acquired actual voltage. At this point, the range adjustment is complete. The voltage acquired by the voltage acquisition unit after range adjustment is taken as the final actual voltage received by the DUT.

[0141] Optionally, after acquiring the actual voltage received by the device under test, the process also includes:

[0142] If the actual voltage is within the range of the voltage acquisition unit, and the difference between the actual voltage and the initial value of the set voltage is within a preset threshold, then the step of determining the set voltage after precision voltage source compensation is executed based on the actual voltage, the initial value of the set voltage, and the preset division formula.

[0143] Specifically, the voltage acquisition unit has an over-range alarm function. If the actual voltage acquired exceeds the currently adaptively adjusted range, the voltage acquisition unit will be unable to acquire the true actual voltage, and the compensation process of the precision voltage source can be terminated. It should be noted that if the voltage is still over-range after adaptive adjustment, the adaptively adjusted range has reached the maximum range achievable by the voltage acquisition unit. Furthermore, if the voltage difference between the actual voltage and the initial value of the set voltage is too large, such as exceeding a preset threshold, compensation may not be possible, and the compensation process can also be terminated. The preset threshold is the maximum threshold that the digital compensation unit can compensate for; in other words, if the voltage difference between the actual voltage and the initial value of the set voltage exceeds the preset threshold, it will exceed the compensation capability of the digital compensation unit. In this embodiment, subsequent compensation actions are only performed when the actual voltage is within the range of the voltage acquisition unit and the difference between the actual voltage and the initial value of the set voltage is within the preset threshold, ensuring the accuracy of compensation and the safe operation of each unit.

[0144] It should be noted that the order of the steps of determining whether the actual voltage is within the range of the voltage acquisition unit and determining whether the difference between the initial value of the actual voltage and the set voltage is within a preset threshold is not limited. Preferably, it can be done by first determining whether the actual voltage is within the range of the voltage acquisition unit, and then determining whether the difference between the initial value of the actual voltage and the set voltage is within a preset threshold.

[0145] Optionally, after acquiring the actual voltage received by the device under test, the process also includes:

[0146] Convert the actual voltage into digital form;

[0147] The set voltage after precision voltage source compensation is determined based on the actual voltage, the initial value of the set voltage, and the preset division formula, including:

[0148] The digital form of the set voltage is determined based on the actual voltage, the initial value of the set voltage, and a preset division formula. The specific working principle described above can be found in the description of the compensation circuit section of the precision voltage source in this invention, and will not be repeated here.

[0149] Optionally, the precision voltage source includes a digital-to-analog converter; after determining the digitally compensated set voltage based on the actual voltage in digital form, the initial value of the set voltage, and a preset division formula, it further includes:

[0150] The set voltage, calibrated in digital form, is then sent to the digital-to-analog converter. The specific conversion principle can be found in the description of the compensation circuit section of the precision voltage source in this invention, and will not be repeated here.

[0151] Optionally, before acquiring the actual voltage received by the device under test, the calibration function of the digital-to-analog converter is also included.

[0152] Specifically, by enabling the calibration function of the digital-to-analog converter, calibration is performed when the digital-to-analog converter controls the output of the precision voltage source, so that the actual voltage output by the precision voltage source is closer to the set voltage, thereby further improving the compensation accuracy.

[0153] For example, Figure 7 A flowchart illustrating another precision voltage source compensation method provided in this embodiment of the invention, taking an FPGA as an example of a digital compensation unit, shows the method comprising:

[0154] Step S101: Detect the four-wire circuit and close the switch.

[0155] Step S102: Call the preset division formula. The host computer can call the preset division formula and write it into the digital compensation unit.

[0156] Step S103: Set the precision voltage source range, set the initial voltage value, and the acquisition mode of the voltage acquisition unit.

[0157] Specifically, this step involves configuring the power supply board on the host computer. The precision voltage source range indicates the range of voltages the precision voltage source can output; the initial voltage value is the voltage expected to be applied across the device under test. The voltage acquisition unit has two acquisition modes: precision mode and high-speed mode. High-speed mode offers faster acquisition speed but lower accuracy; precision mode offers higher accuracy but slower speed. These acquisition modes are well-known to those skilled in the art and will not be elaborated upon here.

[0158] Step S104: Enable the calibration function of the digital-to-analog converter (DAC). That is, before acquiring the actual voltage, the host computer first enables the calibration function of the DAC within the precision voltage source, and also enables the calibration function of the DAC within the voltage acquisition unit.

[0159] Step S105: The precision voltage source outputs voltage and waits for the output voltage to stabilize.

[0160] Specifically, the precision voltage source outputs an analog voltage through a digital-to-analog converter. The voltage may be unstable initially, so a delay is allowed until the output voltage stabilizes before outputting.

[0161] Step S110: Acquire the actual voltage received by the device under test; in this embodiment, step S110 specifically includes step S1101: the voltage acquisition unit adaptively adjusts the range and acquires the actual voltage received by the device under test.

[0162] Step S111: Determine if there is an over-range alarm. That is, determine if the actual voltage is within the range of the voltage acquisition unit after adaptive range adjustment. If the actual voltage is not within the range of the voltage acquisition unit after adaptive range adjustment, the compensation process ends. If the actual voltage is within the range of the voltage acquisition unit after adaptive range adjustment, proceed to step S112.

[0163] Step S112: Calculate the difference between the actual voltage and the initial value of the set voltage;

[0164] Step S113: Determine if the voltage is greater than a preset threshold. That is, determine if the difference between the actual voltage and the initial value of the set voltage is greater than the preset threshold. If not, proceed to step S120; if yes, end the compensation process.

[0165] Step S120: Determine the set voltage after precision voltage source compensation based on the actual voltage, the initial value of the set voltage, and the preset division formula.

[0166] Specifically, the compensated set voltage can be a digital compensation voltage calculated by formula (11).

[0167] Step S130 involves controlling the precision voltage source to output a compensated set voltage; specifically, this may include step S1301, where the digital-to-analog converter outputs an analog set voltage that has been compensated and calibrated, and then waits for the set voltage to stabilize. For example, a delay can be used to wait for the precision voltage source output value to stabilize.

[0168] Step S131: Determine if an overcurrent alarm exists. This involves checking for overcurrent alarms in various parts of the power supply board. If an alarm exists, compensation ends; otherwise, proceed to step S132. Furthermore, overcurrent alarms can be used to further verify the compensated set voltage, confirming its accuracy. For example, if an overcurrent alarm occurs after compensation by the digital compensation unit, it indicates an abnormality in the compensated set voltage. This is because the external impedance remains essentially constant, and higher voltages may experience overcurrent under constant impedance.

[0169] Step S132: Complete one compensation cycle. The compensation method ends.

[0170] For example, with RL = 10KΩ, and the first resistor R1 and the second resistor R2 both = 0.5Ω, the initial value of the voltage is set. Taking 6.5V as an example. Assuming the voltage acquired by the voltage acquisition unit is 6.49935006V, meaning the line loss voltage is approximately 650uV, substituting the relevant parameters into the preset division formula yields a compensated set voltage of 6.500650V. After compensation by the digital compensation unit, the voltage output from the precision voltage source will compensate for the line loss voltage once, achieving a compensation accuracy of tens of uV, thus meeting the voltage accuracy requirements of the chip under test. The compensation accuracy will vary slightly for different set voltage ranges.

[0171] In summary, the beneficial effects of the embodiments of this application include at least the following:

[0172] 1. The embodiments of the present invention can achieve digital compensation of a precision voltage source by using a preset division formula. Through digital compensation, the output voltage of the precision voltage source is made to be close to that of the chip under test. There is no need to use analog devices, which improves the accuracy of the output voltage. The compensation accuracy can reach the microvolt level.

[0173] 2. The voltage acquisition unit in this embodiment of the invention can adaptively adjust the range to acquire voltage, thereby improving the acquisition accuracy of the voltage output from the precision voltage source after line loss. The voltage acquisition unit can also calibrate the acquired voltage and send it to the digital compensation unit for digital compensation, thereby further improving the compensation accuracy.

[0174] 3. Compensation is performed using a preset division formula, achieving high compensation accuracy with a single compensation step. This solves the problem of low compensation accuracy caused by multiple summation calculations in related technologies, which rely on factors such as line conditions and environment. It also avoids voltage source instability caused by multiple summations, thus improving the stability of digital compensation.

[0175] 4. The digital compensation unit is implemented using FPGA, which has a faster control speed compared to other controllers, reaching the nanosecond level, and the calculation time can be completed in the microsecond level. Furthermore, FPGA can compensate for 18 or more channels simultaneously, and can also flexibly control one or more channels to achieve compensation.

[0176] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0177] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A compensation circuit for a precision voltage source, the precision voltage source being used to output a set voltage to the device under test, characterized in that, The compensation circuit of the precision voltage source includes: A voltage acquisition unit is used to be electrically connected to the device under test and to acquire the actual voltage received by the device under test; A digital compensation unit is connected to the precision voltage source and the voltage acquisition unit. The digital compensation unit is used to determine the set voltage after compensation by the precision voltage source based on the actual voltage, the initial value of the set voltage, and a preset division formula. The preset division formula is: ； Among them, V Set_cmp The set voltage after compensation by the precision voltage source; V Set The initial value of the set voltage; V mr The actual voltage is denoted as .

2. The compensation circuit for the precision voltage source according to claim 1, characterized in that, The voltage acquisition unit includes an analog-to-digital converter (ADC), which is electrically connected to the digital compensation unit. The ADC is used to convert the actual voltage into digital form and send it to the digital compensation unit. The digital compensation unit is used to determine the digitally compensated set voltage based on the actual voltage in digital form, the initial value of the set voltage, and a preset division formula; and / or, The digital compensation unit is also used to send the compensated digital form of the set voltage to the precision voltage source after calibration.

3. The compensation circuit for the precision voltage source according to claim 1, characterized in that, The digital compensation unit includes a field-programmable gate array or a microcontroller; and / or, The voltage acquisition unit is also used to adjust the range according to the actual voltage.

4. A compensation method for a precision voltage source, characterized in that, The precision voltage source is used to output a set voltage to the device under test; The compensation method includes: Collect the actual voltage received by the device under test; The set voltage after compensation by the precision voltage source is determined based on the actual voltage, the initial value of the set voltage, and the preset division formula. The precision voltage source is controlled to output the compensated set voltage; The step of determining the set voltage after precision voltage source compensation based on the actual voltage, the initial value of the set voltage, and a preset division formula includes: Substituting the actual voltage and the initial value of the set voltage into the preset division formula, the set voltage after compensation by the precision voltage source is obtained; the preset division formula is: ； Among them, V Set_cmp The set voltage after compensation by the precision voltage source; V Set The initial value of the set voltage; V mr The actual voltage is denoted as .

5. The compensation method for the precision voltage source according to claim 4, characterized in that, The acquisition of the actual voltage received by the device under test includes: The voltage acquisition unit adaptively adjusts its range and acquires the actual voltage received by the device under test; And / or, after acquiring the actual voltage received by the device under test, the method further includes: If the actual voltage is within the range of the voltage acquisition unit, and the difference between the actual voltage and the initial value of the set voltage is within a preset threshold, then the step of determining the set voltage after precision voltage source compensation based on the actual voltage, the initial value of the set voltage, and a preset division formula is executed.

6. The compensation method for the precision voltage source according to claim 4, characterized in that, After acquiring the actual voltage received by the device under test, the process also includes: Convert the actual voltage into digital form; The step of determining the set voltage after precision voltage source compensation based on the actual voltage, the initial value of the set voltage, and a preset division formula includes: The digitally compensated set voltage is determined based on the actual voltage in digital form, the initial value of the set voltage, and a preset division formula. The precision voltage source includes a digital-to-analog converter; After determining the digitally compensated set voltage based on the actual voltage in digital form, the initial value of the set voltage, and the preset division formula, the process further includes: The compensated digital form of the set voltage is calibrated and then sent to the digital-to-analog converter.

7. The compensation method for a precision voltage source according to claim 6, characterized in that, Before acquiring the actual voltage received by the device under test, the following steps are also included: Enable the calibration function of the digital-to-analog converter.

8. A power supply board, characterized in that, The power supply board includes at least one test channel; The test channel includes a precision voltage source and a compensation circuit for the precision voltage source as described in any one of claims 1-3; the test channel also includes a high-side output, a low-side output, a high-side sensing sensor, and a low-side sensing sensor. The first terminal of the precision voltage source is electrically connected to the high-end output, and the second terminal of the precision voltage source is electrically connected to the low-end output. The first end of the voltage acquisition unit is electrically connected to the sensing high end, and the second end of the voltage acquisition unit is electrically connected to the sensing low end.

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