Resistance gradient effect compensation method and voltage sampling circuit

Abstract

The embodiment of the invention provides a resistance gradient effect compensation method and a voltage sampling circuit, and the method comprises the steps: dividing a divider resistor in the voltage sampling circuit into a high-order divider resistor and a low-order divider resistor, the high-order divider resistor and the low-order divider resistor are three-end resistors, connecting the third end of the high-order divider resistor with a power supply voltage, and connecting the second end of the low-order divider resistor with a power supply voltage; the third end of the low-level divider resistor is connected with sub potential; and adjusting the number of serially connected resistors of the high-level divider resistor, so that the deviation between the total resistance value of the high-level divider resistor and the low-level divider resistor and a target value is smaller than a preset deviation, and the target value is the sum of the ideal resistance values of the high-level divider resistor and the low-level divider resistor.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to the field of integrated circuits, and in particular, to a method for compensating a resistance gradient effect, a voltage sampling circuit, and a chip. Background Art

[0002] In integrated circuits (ICs), resistor string voltage division is a common voltage sampling method. Through the voltage division resistor, the IC can effectively obtain the voltage information of the PIN pin. However, resistors are not ideal linear components. When the gradient effect exists, the change in the resistance value of the resistor will affect the voltage division ratio and sampling accuracy. Specifically, when the voltage distribution across the resistor is uneven, or the voltage of the environment in which the resistor is located is different from the average value of the voltage across the resistor, the resistance value of the resistor will change, thereby affecting the voltage division ratio and reducing the accuracy of the sampled voltage.

[0003] In order to deal with the sampling errors caused by resistor nonlinearity and gradient effects, some compensation measures are often needed to ensure high accuracy of voltage division. For example, using temperature compensation resistors to reduce the error caused by temperature changes in resistance values; or performing high-precision calibration through digital compensation circuits. These methods require increased process or control costs. Summary of the invention

[0004] In order to solve the problem of voltage-dividing ratio deviation of a resistor string caused by the gradient effect of the resistor, the embodiments described in this article provide a compensation method for the resistor gradient effect and a voltage sampling circuit, by dividing the voltage-dividing resistors into high-position voltage-dividing resistors and low-position voltage-dividing resistors according to their positions, and using low-position correction resistors to further compensate for the sampling error, so as to achieve an ideal voltage-dividing ratio and improve the voltage sampling accuracy.

[0005] According to a first aspect of the present disclosure, a method for compensating for a resistance gradient effect is provided, comprising: dividing a voltage-dividing resistor in a voltage sampling circuit into a high-order voltage-dividing resistor and a low-order voltage-dividing resistor, wherein both the high-order voltage-dividing resistor and the low-order voltage-dividing resistor are three-terminal resistors, connecting the third terminal of the high-order voltage-dividing resistor to a power supply voltage, and connecting the third terminal of the low-order voltage-dividing resistor to a sub potential; and adjusting the number of series resistors of the high-order voltage-dividing resistor so that the deviation between the total resistance value of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor and a target value is less than a preset deviation, and the target value is the sum of the ideal resistance values ​​of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor.

[0006] In some embodiments of the present disclosure, the ideal resistance values ​​of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor are equal, and the same materials, processes and dimensions are used. The resistance value of the high-order voltage-dividing resistor is greater than the ideal resistance value, and the resistance value of the low-order voltage-dividing resistor is less than the ideal resistance value.

[0007] In some embodiments of the present disclosure, multiple low-order correction resistors and their corresponding switching tubes are set at the low potential end of the low-order voltage-divider resistor; the minimum correction step size and the step size of each low-order correction resistor are set; according to the deviation between the total resistance value of the high-order voltage-divider resistor and the low-order voltage-divider resistor and the target value and the resistance step size of the low-order correction resistor, the conduction state of the corresponding switching tube is controlled to compensate for the error.

[0008] In some embodiments of the present disclosure, setting the minimum correction step size and the step size of each low-order correction resistor includes: setting the minimum correction step size based on the deviation range between the estimated total resistance value of the high-order voltage divider resistor and the low-order voltage divider resistor and the target value; setting a different step size for each low-order correction resistor according to the minimum correction step size; and removing the maximum correction step size of the low-order correction resistor from the resistance value of the low-order voltage divider resistor.

[0009] In some embodiments of the present disclosure, the conduction state of the corresponding switch tube is controlled according to the deviation between the total resistance of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor and the target value and the resistance step of the low-order correction resistor to compensate for the error, including: calculating the voltage sampling error according to the deviation between the total resistance of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor and the target value, setting the correction code value of each switch tube according to the voltage sampling error, and controlling the conduction state of the switch tube according to the correction code value: when the correction code value is 1, the switch tube is turned on, and the corresponding low-order correction resistor is short-circuited in the voltage sampling circuit; when the correction code value is 0, the switch tube is disconnected, and the corresponding low-order correction resistor is connected in series in the voltage sampling circuit.

[0010] According to the second aspect of the present disclosure, a voltage sampling circuit is provided, comprising: a high-order voltage-dividing resistor, a low-order voltage-dividing resistor and a low-order correction resistor, one end of the high-order voltage-dividing resistor is connected to a power supply input end, and the other end is connected to the low-order voltage-dividing resistor, the low potential end of the low-order voltage-dividing resistor is connected to the low-order correction resistor, and corresponding switching tubes are connected in parallel at both ends of each low-order correction resistor, and the number of series resistors of the high-order voltage-dividing resistor and the conduction state of the switching tube are determined according to the compensation method for the resistance gradient effect of the first aspect of the present disclosure.

[0011] Furthermore, in the voltage sampling circuit of the embodiment of the present disclosure, the high-order voltage-dividing resistor and the low-order voltage-dividing resistor are separated by a preset distance, and each high-order voltage-dividing resistor and the low-order voltage-dividing resistor adopt the same material, process and size.

[0012] Furthermore, in the voltage sampling circuit of the embodiment of the present disclosure, the high-order voltage-dividing resistor and the low-order voltage-dividing resistor are both three-terminal resistors, the third end of the high-order voltage-dividing resistor is connected to the power supply voltage, and the third end of the low-order voltage-dividing resistor is connected to the sub potential.

[0013] Furthermore, in the voltage sampling circuit of the embodiment of the present disclosure, when the switch tube is turned on, the corresponding low-level correction resistor is short-circuited in the voltage sampling circuit, and when the switch tube is turned off, the corresponding low-level correction resistor is connected in series in the voltage sampling circuit.

[0014] According to a third aspect of the present disclosure, a chip is provided. The chip includes the voltage sampling circuit according to the second aspect of the present disclosure, and the voltage sampling circuit determines the number of series resistors of the high-order voltage-dividing resistor and the conduction state of the switch tube according to the compensation method of the resistance gradient effect of the first aspect of the present disclosure, so as to achieve the purpose of compensating the voltage-dividing error. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly described below. It should be noted that the drawings described below only relate to some embodiments of the present disclosure, but are not intended to limit the present disclosure, wherein:

[0016] Figure 1 It is an uncompensated voltage sampling circuit;

[0017] Figure 2 Schematic diagram of the circuit structure of a voltage sampling circuit according to an embodiment of the present disclosure.

[0018] It should be noted that the elements in the drawings are schematic and not drawn to scale. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative work also fall within the scope of protection of the present disclosure.

[0020] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by a person skilled in the art to which the subject matter of the present disclosure belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the specification and the relevant art, and will not be interpreted in an idealized or overly formal form unless otherwise explicitly defined herein. As used herein, a statement that two or more parts are "connected" or "coupled" together shall mean that the parts are joined together directly or through one or more intermediate components.

[0021] Figure 1 It is an uncompensated voltage sampling circuit. Figure 1As shown, resistors R1, R2......R k ......R n are three-terminal resistors. Two of their terminals are connected in series in the sampling circuit, and the third terminal represents the potential at which the resistor is placed (usually the resistor is placed at the sub potential). When the resistor gradient effect is not considered, R1 = R2 = R k = R n = R, then the sampling voltage is However, when considering the resistor gradient, R k ≈ R * (1 - m * (V k + V k-1 - 2 * V z )) < R, where Vz is the voltage at the third terminal, Vz = 0V, m is a process parameter greater than 0, usually on the order of 10 -4 of magnitude, and R is the ideal resistance value.

[0022] Generally, the V OUT collected under high voltage should be able to be processed by the subsequent stage. Usually, the voltage division ratio is relatively large, and the voltage borne by R1 is very small. Taking the sampling ratio of 1 / 10 as an example (k = 1, n = 10), the resistor gradient effect of R1 can be basically ignored, that is, R1 ≈ R, while the resistance between V OUT and V bus is relatively small, that is, R2 + R3 + … R 10 < 9R. Therefore, the sampling voltage That is, the voltage division ratio will be relatively large. In the case of a relatively high V bus , it will be even larger, which is unacceptable in applications with high precision requirements.

[0023] In view of the voltage division error problem caused by the non-uniformity of resistor characteristics, the embodiments of the present disclosure propose a compensation method for the resistor gradient effect and a voltage sampling circuit applying the resistor compensation method, which dynamically compensates for the voltage distribution error caused by process mismatch and voltage gradient effect by finely designing the resistor network.

[0024] In an embodiment of the present disclosure, the voltage dividing resistors in the voltage sampling circuit are divided into high-position voltage dividing resistors and low-position voltage dividing resistors according to their positions. Both the high-position voltage dividing resistors and the low-position voltage dividing resistors are three-terminal resistors. The third terminal of the high-position voltage dividing resistor is connected to the power supply voltage, and the third terminal of the low-position voltage dividing resistor is connected to the sub potential. Among them, the sub potential is usually the lowest potential of the chip.

[0025] By adjusting the number of series resistors of the high - voltage voltage - dividing resistors, that is, reasonably adjusting the ratio of the number of high - voltage and low - voltage voltage - dividing resistors, the deviation between the total resistance values of the high - voltage and low - voltage voltage - dividing resistors and the target value can be made less than the preset deviation. Among them, the target value is the sum of the ideal resistance values of the high - voltage and low - voltage voltage - dividing resistors. The ideal resistance values of the high - voltage and low - voltage voltage - dividing resistors are equal and are made of the same material, process, and size. At the same time, the performance is further optimized by the low - voltage correction resistors at the low - voltage side.

[0026] Figure 2 FIG. is a schematic circuit diagram of a voltage sampling circuit according to an embodiment of the present disclosure. Refer to Figure 2 As shown, the voltage sampling circuit includes: a high - voltage voltage - dividing resistor, a low - voltage voltage - dividing resistor, and a low - voltage correction resistor. One end of the high - voltage voltage - dividing resistor is connected to the power input terminal Vbus, and the other end is connected to the low - voltage voltage - dividing resistor. The low - potential end of the low - voltage voltage - dividing resistor is connected to the low - voltage correction resistor, and a corresponding switching transistor is connected in parallel across each low - voltage correction resistor. That is to say, the potentials borne by the high - voltage voltage - dividing resistor, the low - voltage voltage - dividing resistor, and the low - voltage correction resistor decrease in sequence. The function of the low - voltage correction resistor is to finely adjust the low - voltage voltage - dividing resistor.

[0027] Refer to Figure 2 As shown, the present disclosure exemplarily connects the third ends of (x + 1) high - voltage voltage - dividing resistors (R n-1-x ...R n-1 、R n ) to the Vbus voltage, and connects the third ends of (n - x - 1) low - voltage voltage - dividing resistors (R1, R2...R k ...R n ) to the sub potential, that is, the lowest potential of the chip.

[0028] For the low - voltage voltage - dividing resistor, R k ≈R*(1 - m*(V k +V k-1 -2*V z ))<R; where R k is the k - th low - voltage voltage - dividing resistor, R is the ideal resistance value, m is a process parameter greater than 0, usually on the order of 10 -4 , and Vz is the voltage at the third end. Since its third end is connected to the sub potential and Vz = 0V, it can be seen that the resistance value of the low - voltage voltage - dividing resistor is less than the ideal resistance value R.

[0029] For the high - voltage voltage - dividing resistor, since the voltage division Vn of the n - th high - voltage voltage - dividing resistor R n and the voltage division Vn - 1 of the (n - 1) - th high - voltage voltage - dividing resistor R n-1 are both obtained by voltage division from Vbus, so

[0030] V n <Vbus ,V n-1 <V bus

[0031] The resistance of the high voltage divider resistor is greater than the ideal resistance, that is, R n ≈R*(1-m*(V n +V n-1 -2*V bus ))>R; where R n is the nth high-level voltage divider resistor, R is the ideal resistance, and m is a process parameter greater than 0, usually 10 -4 The magnitude of Vz is the third terminal voltage, and the third terminals of these high-position voltage-dividing resistors are connected to the power supply voltage Vbus.

[0032] Therefore, by adjusting the number of series resistors of the high-order voltage-dividing resistor (x+1), the deviation between the total resistance of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor and the target value can be made smaller than the preset deviation, that is, the total resistance of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor is close to the sum of the ideal resistance values, thereby achieving an ideal voltage-dividing ratio. For example, the deviation between the total resistance and the target value can be set to not exceed ±1%. By reasonably selecting the ratio of the number of high-order voltage-dividing resistors and low-order voltage-dividing resistors (x+1 and nx-1), it can be ensured that the deviation between the total resistance of the final voltage-dividing circuit and the target value is within an acceptable range.

[0033] The disclosed embodiments further take into account that when some resistors are placed at high positions and some resistors are placed at low positions, there will be a certain physical distance between the high-position voltage-dividing resistors and the low-position voltage-dividing resistors, and the resistors at different positions will have resistance deviations during the manufacturing process. This process mismatch will cause the actual resistance values ​​of these resistors to be different from the design values, resulting in a large discreteness in the voltage-dividing results, that is, the deviation between the resistance value of the high-position voltage-dividing resistor and the ideal resistance value does not match the deviation between the resistance value of the low-position resistor and the ideal resistance value, resulting in a certain voltage-dividing error.

[0034] Therefore, the embodiment of the present disclosure sets a plurality of low-level correction resistors and their corresponding switch tubes at the low potential end of the low-level voltage divider resistor, so as to compensate for the deviation caused by the inconsistent process by dynamically adjusting the low-level correction resistor value in the circuit. The switch tube can be a MOSFET, a CMOS switch or a transmission gate. The selection of the switch tube should ensure good isolation between the low potential and the low-level correction resistor, and can efficiently control the access of the low-level correction resistor.

[0035] Reference Figure 2 As shown in the figure, low-level trim resistors (Rtrim0-Rtrimy) are used to further compensate for the resistance deviation caused by process mismatch or voltage gradient effect. Each low-level trim resistor is matched with a switch (Q0-Q y), by controlling different switches, the resistance of the resistor network is dynamically adjusted to achieve an accurate voltage division value. The control signal is Trim0-Trimy, where 0 means the switch is open and 1 means the switch is closed.

[0036] Then, the minimum correction step and the step of each low-order correction resistor are set. According to an embodiment of the present disclosure, the minimum correction step can be set according to the deviation range between the estimated total resistance of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor and the target value; then, the different step of each low-order correction resistor is set according to the minimum correction step; and the maximum correction step of the low-order correction resistor is removed from the resistance of the low-order voltage-dividing resistor.

[0037] Set the minimum correction step size, which is the minimum accuracy requirement. Select the appropriate resistance step size according to the estimated error range. Assuming the estimated deviation range is ±1%, the different correction resistance values ​​of the low-level correction resistors can be set to 1‰, 2‰, 4‰, 8‰, and 16‰, corresponding to Rtrim0-Rtrim4 respectively. The settings of these correction resistors can cover the error range of ±1% to ensure compensation accuracy.

[0038] Since the sampling error may be positive or negative, a small step of resistance can be deducted from the low-level resistor to achieve compensation in the positive and negative directions. For example, a resistance value of 16‰ is deducted from the low-level resistor R1, so that when making corrections, the resistance value can be corrected by adding the Trim resistor.

[0039] Finally, according to the deviation between the total resistance of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor and the target value and the resistance step of the low-order correction resistor, the conduction state of the corresponding switch tube is controlled to compensate for the error. That is, each Trim resistor is controlled by the corresponding Trim switch (Q0-Qy), and the switch control signal is Trim0-Trimy, and the control method is as follows: The Trim signal is 0, indicating that the switch tube is disconnected, and the corresponding Trim resistor participates in the circuit. The Trim signal is 1, indicating that the switch tube is turned on, and the corresponding Trim resistor is not connected to the circuit. By flexibly adjusting these switches, different Trim resistors can be gradually introduced into the circuit to accurately compensate for the deviation of the resistance value.

[0040] Specifically, the voltage sampling error is calculated based on the deviation between the total resistance of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor and the target value, the correction code value of each switch tube is set according to the voltage sampling error, and the conduction state of the switch tube is controlled according to the correction code value: when the correction code value is 1, the switch tube is turned on, and the corresponding low-order correction resistor is short-circuited in the voltage sampling circuit, and the corresponding correction resistor does not participate in the voltage dividing circuit; when the correction code value is 0, the switch tube is disconnected, and the corresponding low-order correction resistor is connected in series in the voltage sampling circuit.

[0041] Assuming the sampling error is -8‰, you need to add 8‰ of resistance to compensate for this negative deviation. You can calculate the trim value that needs to be compensated based on this error, and compensate for the 8‰ error by setting the corresponding Trim switch. The specific compensation steps are as follows:

[0042] Set Trim0-Trim2 and Trim4 to 1, so that Rtrim0, Rtrim1, Rtrim2, and Rtrim4 can be short-circuited. Set Trim3 to 0, and then the Rtrim3 resistor is connected in series to the compensation path, increasing the resistance by 8‰ to achieve the purpose of compensating the error.

[0043] Therefore, by introducing the Trim resistor and the Trim switch, the process mismatch caused by the long physical distance of the resistors can be effectively compensated, and the resistor error can be compensated by precise step adjustment. This method provides high-precision error compensation and is suitable for application environments with large manufacturing errors, ensuring the stability and accuracy of the voltage distribution circuit under various conditions.

[0044] The embodiment of the present disclosure also provides a chip. The chip includes a voltage sampling circuit according to the embodiment of the present disclosure, in which the number of series resistors of the high-order voltage-dividing resistor and the conduction state of the switch tube corresponding to the low-order correction resistor in the voltage sampling circuit are determined according to the compensation method of the resistance gradient effect provided by the embodiment of the present disclosure, and can be applied to circuits with high requirements on accuracy and stability, such as high-precision ADC (analog-to-digital converter) and sensor signal sampling circuit.

[0045] In summary, according to the compensation method for the resistance gradient effect and the voltage sampling circuit of the embodiment of the present disclosure, by reasonably designing the number ratio of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor, and introducing the low-order correction resistor, it is possible to effectively compensate for the errors caused by the voltage gradient effect and the process mismatch, and improve the voltage division accuracy. The voltage division value can be adjusted in real time according to the measurement results to compensate for different errors. This compensation mechanism makes the system flexible in practical applications, and can cope with different resistance deviations and meet different accuracy requirements.

[0046] Unless the context clearly indicates otherwise, the singular form of the words used herein and in the appended claims includes the plural and vice versa. Thus, when referring to the singular, the plural form of the corresponding term is generally included. Similarly, the words "comprise" and "include" are to be interpreted as inclusive rather than exclusive. Likewise, the terms "include" and "or" should be interpreted as inclusive unless such interpretation is expressly prohibited herein. Where the term "example" is used herein, particularly when it is located after a group of terms, the "example" is merely exemplary and illustrative and should not be considered exclusive or comprehensive.

[0047] Further aspects and scopes of adaptability become apparent from the description provided herein. It should be understood that various aspects of the present application can be implemented individually or in combination with one or more other aspects. It should also be understood that the description and specific embodiments herein are intended for purposes of illustration only and are not intended to limit the scope of the present application.

[0048] Several embodiments of the present disclosure are described in detail above, but it is obvious that those skilled in the art can make various modifications and variations to the embodiments of the present disclosure without departing from the spirit and scope of the present disclosure. The protection scope of the present disclosure is defined by the attached claims.

Claims

1. A method for compensating a resistance gradient effect, characterized in that: include: The voltage-dividing resistor in the voltage sampling circuit is divided into a high-order voltage-dividing resistor and a low-order voltage-dividing resistor, wherein both the high-order voltage-dividing resistor and the low-order voltage-dividing resistor are three-terminal resistors, the third terminal of the high-order voltage-dividing resistor is connected to the power supply voltage, and the third terminal of the low-order voltage-dividing resistor is connected to the sub potential; as well as The number of series resistors of the high-order voltage-dividing resistor is adjusted so that the deviation between the total resistance of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor and the target value is less than a preset deviation, and the target value is the sum of the ideal resistance values ​​of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor.

2. The compensation method according to claim 1, characterized in that: The ideal resistance values ​​of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor are equal, and they adopt the same material, process and size. The resistance value of the high-order voltage-dividing resistor is greater than the ideal resistance value, and the resistance value of the low-order voltage-dividing resistor is less than the ideal resistance value.

3. The compensation method according to claim 1, characterized in that: The method further comprises: A plurality of low-level correction resistors and corresponding switch tubes are arranged at the low potential end of the low-level voltage-dividing resistor; Set the minimum trim step size and the step size for each low trim resistor; and According to the deviation between the total resistance of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor and the target value and the resistance step of the low-order correction resistor, the conduction state of the corresponding switch tube is controlled to compensate for the error.

4. The compensation method according to claim 1, characterized in that: The step of setting the minimum correction step size and the step size of each low-level correction resistor includes: Setting a minimum correction step length according to a deviation range between the estimated total resistance value of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor and a target value; Setting different step sizes of each low-level correction resistor according to the minimum correction step size; and The maximum correction step length of the low-order correction resistor is subtracted from the resistance value of the low-order voltage-dividing resistor.

5. The compensation method according to claim 1, characterized in that: According to the deviation between the total resistance of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor and the target value and the resistance step of the low-order correction resistor, controlling the conduction state of the corresponding switch tube to compensate for the error includes: The voltage sampling error is calculated based on the deviation between the total resistance of the high-order voltage-dividing resistor and the low-order voltage-dividing resistor and the target value, the correction code value of each switch tube is set according to the voltage sampling error, and the conduction state of the switch tube is controlled according to the correction code value: when the correction code value is 1, the switch tube is turned on, and the corresponding low-order correction resistor is short-circuited in the voltage sampling circuit; when the correction code value is 0, the switch tube is disconnected, and the corresponding low-order correction resistor is connected in series in the voltage sampling circuit.

6. A voltage sampling circuit, characterized in that: include: A high-order voltage-dividing resistor, a low-order voltage-dividing resistor and a low-order correction resistor, one end of the high-order voltage-dividing resistor is connected to the power input end, and the other end is connected to the low-order voltage-dividing resistor, the low potential end of the low-order voltage-dividing resistor is connected to the low-order correction resistor, and corresponding switching tubes are connected in parallel at both ends of each low-order correction resistor, and the number of series resistors of the high-order voltage-dividing resistor and the conduction state of the switching tube are determined according to the compensation method for the resistance gradient effect described in any one of claims 1-5.

7. The voltage sampling circuit according to claim 6, characterized in that: The high-order voltage-dividing resistor and the low-order voltage-dividing resistor are separated by a preset distance, and each high-order voltage-dividing resistor and the low-order voltage-dividing resistor are made of the same material, process and size.

8. The voltage sampling circuit according to claim 6, characterized in that: The high-order voltage-dividing resistor and the low-order voltage-dividing resistor are both three-terminal resistors, the third terminal of the high-order voltage-dividing resistor is connected to the power supply voltage, and the third terminal of the low-order voltage-dividing resistor is connected to the sub potential.

9. The voltage sampling circuit according to claim 6, characterized in that: When the switch tube is turned on, the corresponding low-level correction resistor is short-circuited in the voltage sampling circuit, and when the switch tube is turned off, the corresponding low-level correction resistor is connected in series in the voltage sampling circuit.

10. A chip, characterized in that: The method comprises a voltage sampling circuit according to any one of claims 6 to 9.

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