Compensation methods for resistance gradient effect and voltage sampling circuit

Abstract

The embodiments of this disclosure provide a method for compensating for the resistance gradient effect and a voltage sampling circuit. The method includes: dividing the voltage dividing resistors in the voltage sampling circuit into high-order voltage dividing resistors and low-order voltage dividing resistors, both of which are three-terminal resistors; connecting the third terminal of the high-order voltage dividing resistor to the power supply voltage; and connecting the third terminal of the low-order voltage dividing resistor to the sub-potential; and adjusting the number of series resistors in the high-order voltage dividing resistors so that the deviation between the total resistance of the high-order and low-order voltage dividing resistors and the target value is less than a preset deviation, wherein the target value is the sum of the ideal resistance values ​​of the high-order and low-order voltage dividing resistors.

Description

Technical Field

[0001] Embodiments of this disclosure relate to the field of integrated circuits, and more specifically, to a method for compensating for resistance gradient effects, a voltage sampling circuit, and a chip. Background Technology

[0002] In integrated circuits (ICs), resistor series voltage division is a common voltage sampling method. By using the dividing resistors, the IC can effectively obtain the voltage information of the pins. However, resistors are not ideal linear components. When gradient effects exist, changes in the resistor value can affect the voltage division ratio and sampling accuracy. Specifically, when the voltage distribution across the resistor is uneven, or when the voltage of the environment around the resistor differs from the average voltage across the resistor, the resistor value will change, thus affecting the voltage division ratio and reducing the accuracy of the sampled voltage.

[0003] To address sampling errors caused by resistance nonlinearity and gradient effects, compensation measures are often required to ensure high accuracy of the voltage divider. For example, temperature-compensating resistors can be used to reduce errors in resistance values ​​caused by temperature variations; alternatively, high-precision calibration can be performed using digital compensation circuits. These methods, however, increase manufacturing or control costs. Summary of the Invention

[0004] To address the voltage division ratio deviation caused by the resistor gradient effect, the embodiments described herein provide a method for compensating for the resistor gradient effect and a voltage sampling circuit. By classifying the voltage divider resistors into high-order and low-order voltage divider resistors according to their positions, and using a low-order correction resistor to further compensate for sampling errors, an ideal voltage division ratio can be achieved, thereby improving voltage sampling accuracy.

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

[0006] In some embodiments of this disclosure, the ideal resistance values ​​of the high-order voltage divider resistor and the low-order voltage divider resistor are equal, and they are made of the same material, process and size. The resistance value of the high-order voltage divider resistor is greater than the ideal resistance value, and the resistance value of the low-order voltage divider resistor is less than the ideal resistance value.

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

[0008] In some embodiments of this 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 resistors and the low-order voltage divider resistors and the target value; setting different step sizes 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 resistors from the resistance value of the low-order voltage divider resistors.

[0009] In some embodiments of this disclosure, controlling the conduction state of the corresponding switching transistors to compensate for errors based on the deviation between the total resistance of the high-order and low-order voltage divider resistors and the target value, and the resistance step size of the low-order correction resistor, includes: calculating the voltage sampling error based on the deviation between the total resistance of the high-order and low-order voltage divider resistors and the target value; setting the correction code value for each switching transistor based on the voltage sampling error; and controlling the conduction state of the switching transistors based on the correction code value: when the correction code value is 1, the switching transistor is turned on, and the corresponding low-order correction resistor is shorted in the voltage sampling circuit; when the correction code value is 0, the switching transistor is turned off, and the corresponding low-order correction resistor is connected in series in the voltage sampling circuit.

[0010] According to a second aspect of this disclosure, a voltage sampling circuit is provided, comprising: a high-order voltage divider resistor, a low-order voltage divider resistor, and a low-order correction resistor. One end of the high-order voltage divider resistor is connected to a power input terminal, and the other end is connected to the low-order voltage divider resistor. The low-potential end of the low-order voltage divider resistor is connected to the low-order correction resistor. A corresponding switching transistor is connected in parallel across each low-order correction resistor. The number of series resistors in the high-order voltage divider resistor and the conduction state of the switching transistor are determined according to the resistance gradient effect compensation method of the first aspect of this disclosure.

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

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

[0013] Furthermore, in the voltage sampling circuit of this embodiment, when the switching transistor is turned on, the corresponding low-order correction resistor is shorted in the voltage sampling circuit, and when the switching transistor is turned off, the corresponding low-order correction resistor is connected in series in the voltage sampling circuit.

[0014] According to a third aspect of this disclosure, a chip is provided. The chip includes a voltage sampling circuit according to a second aspect of this disclosure, which determines the number of series resistors for the high-order voltage divider resistors and the on-state of the switching transistor based on a compensation method for the resistance gradient effect of a first aspect of this disclosure, in order to compensate for voltage division errors. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly described below. It should be understood that the drawings described below only relate to some embodiments of this disclosure and are not intended to limit this disclosure, wherein:

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

[0017] Figure 2 This is a 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 attached diagram are schematic and not drawn to scale. Detailed Implementation

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

[0020] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter pertains. It will be further understood that terms such as those defined in commonly used dictionaries shall be interpreted as having the meaning consistent with their meaning in the context of the specification and in the relevant art, and shall not be interpreted in an idealized or overly formal form unless otherwise explicitly defined herein. As used herein, the statement of “connecting” or “coupling” two or more parts together shall mean that these parts are directly joined together or joined through one or more intermediate components.

[0021] Figure 1 This is an uncompensated voltage sampling circuit. For example... 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 not considering the resistor gradient effect, 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 and R is the ideal resistance value.

[0022] Generally, the V OUT collected under high voltage needs to 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 basically be 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 resistor gradient effect and a voltage sampling circuit applying the resistor compensation method, which dynamically compensates 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, by 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. Here, 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 they use 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: high - voltage voltage - dividing resistors, low - voltage voltage - dividing resistors, and low - voltage correction resistors. 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-order voltage divider resistor is greater than the ideal resistance, i.e., R n ≈R*(1-m*(V n +V n-1 -2*V bus ))>R; where R n This is the nth high-order voltage divider resistor, where R is the ideal resistance value and m is a process parameter greater than 0, typically 10. -4 The magnitude is Vz, which is the third terminal voltage. The third terminal of these high-order voltage divider resistors is connected to the power supply voltage Vbus.

[0032] Therefore, by adjusting the number of series resistors in the high-order voltage divider (x+1), the deviation between the total resistance of the high-order and low-order voltage divider resistors and the target value can be made less than a preset deviation. That is, the total resistance of the high-order and low-order voltage divider resistors is close to the sum of their ideal resistances, thus achieving the ideal voltage division ratio. For example, the deviation between the total resistance and the target value can be set to no more than ±1%. By reasonably selecting the ratio of the high-order and low-order voltage divider resistors (x+1 and nx-1), it can be ensured that the deviation between the final total resistance of the voltage divider circuit and the target value is within an acceptable range.

[0033] This embodiment further considers that when some resistors are placed in high positions and some resistors are placed in low positions, there is a certain physical distance between the high-position voltage divider resistors and the low-position voltage divider resistors. Resistors in different positions have resistance value deviations during the manufacturing process. This process mismatch will cause the actual resistance value of these resistors to be different from the design value, resulting in a large dispersion of the voltage division result. That is, the deviation between the resistance value of the high-position voltage divider resistor and the ideal resistance value is mismatched with the deviation between the resistance value of the low-position resistor and the ideal resistance value, resulting in a certain voltage division error.

[0034] Therefore, in this embodiment, multiple low-level correction resistors and their corresponding switching transistors are provided at the low-potential end of the low-level voltage divider resistors to compensate for deviations caused by process inconsistencies by dynamically adjusting the value of the low-level correction resistors in the circuit. The switching transistors can be MOSFETs, CMOS switches, or transmission gates. The selection of the switching transistors should ensure good isolation between the low potential and the low-level correction resistors, while also efficiently controlling the connection of the low-level correction resistors.

[0035] Reference Figure 2 As shown, low-order correction resistors (Rtrim0-Rtrimy) are used to further compensate for resistance deviations caused by process mismatch or voltage gradient effects. Each low-order correction resistor is paired with a switch (Q0-Q). yBy controlling different switches, the resistance value of the resistor network is dynamically adjusted to achieve a precise voltage division value. The control signal is Trim0-Trimy, where 0 indicates that the switch is open and 1 indicates that the switch is closed.

[0036] Then, a minimum correction step size and a step size for each low-order correction resistor are set. According to embodiments of this disclosure, a minimum correction step size can be set based on the deviation range between the estimated total resistance of the high-order and low-order voltage divider resistors and the target value; then, a different step size for each low-order correction resistor is set according to the minimum correction step size; and a maximum correction step size is set by removing the low-order correction resistor from the resistance value of the low-order voltage divider resistor.

[0037] Setting the minimum correction step size represents the minimum accuracy requirement. Based on the estimated error range, select an appropriate resistance step size. Assuming the estimated deviation range is ±1%, different correction resistance values ​​for the lower-order correction resistors can be set to 1‰, 2‰, 4‰, 8‰, and 16‰, corresponding to Rtrim0-Rtrim4 respectively. These correction resistor settings can cover an error range of ±1% to ensure compensation accuracy.

[0038] Since sampling errors can be positive or negative, compensation in either direction can be achieved by subtracting a small step value from the low-order resistor. For example, subtracting 16‰ of the resistance value from the low-order resistor R1 allows the resistance value to be corrected by adding a Trim resistor during correction.

[0039] Finally, based on the deviation between the total resistance of the high-order and low-order voltage divider resistors and the target value, and the resistance step size of the low-order correction resistor, the corresponding switching transistor's conduction state is controlled to compensate for the error. That is, each Trim resistor is controlled by a corresponding Trim switch (Q0-Qy), with the switch control signal being Trim0-Trimy. The control method is as follows: a Trim signal of 0 indicates that the switching transistor is off, and the corresponding Trim resistor participates in the circuit. A Trim signal of 1 indicates that the switching transistor is 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 resistance value deviation.

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

[0041] Assuming a sampling error of -8‰, an 8‰ resistor needs to be added to compensate for this negative deviation. The required trim value can be calculated based on this error, and the 8‰ error can be compensated by setting the appropriate trim switch. The specific compensation steps are as follows:

[0042] Setting Trim0-Trim2 and Trim4 to 1 allows Rtrim0, Rtrim1, Rtrim2, and Rtrim4 to be short-circuited. Setting Trim3 to 0 connects the Rtrim3 resistor in series with the compensation path, adding 0.8% resistance to compensate for the error.

[0043] Therefore, by introducing Trim resistors and Trim switches, process mismatches caused by large physical distances between resistors can be effectively compensated, and resistor errors can be compensated through precise step size adjustment. This method provides high-precision error compensation, is suitable for applications with large manufacturing errors, and ensures the stability and accuracy of voltage distribution circuits under various conditions.

[0044] Embodiments of this disclosure also provide a chip. This chip includes a voltage sampling circuit according to embodiments of this disclosure. The number of series resistors for the high-order voltage divider resistors and the conduction state of the switching transistors corresponding to the low-order correction resistors in this voltage sampling circuit are determined according to a resistance gradient effect compensation method provided in embodiments of this disclosure. This method can be applied to circuits with high precision and stability requirements, such as high-precision ADCs (analog-to-digital converters) and sensor signal sampling circuits.

[0045] In summary, the resistance gradient effect compensation method and voltage sampling circuit according to the embodiments of this disclosure, by rationally designing the ratio of high-order and low-order voltage divider resistors and introducing a low-order correction resistor, can effectively compensate for errors caused by voltage gradient effects and process mismatches, thereby improving voltage division accuracy. The voltage divider value can be adjusted in real time based on the measurement results to compensate for different errors. This compensation mechanism makes the system flexible in practical applications, capable of handling different resistance deviations and meeting different accuracy requirements.

[0046] Unless otherwise expressly indicated by the context, the singular form of words used herein and in the appended claims includes the plural form, and vice versa. Thus, when referring to the singular, the plural form of the corresponding term is generally included. Similarly, the terms “comprising” and “including” shall be interpreted as including rather than exclusively. Likewise, the terms “including” and “or” shall be interpreted as including unless such interpretation is expressly prohibited herein. Where the term “example” is used herein, particularly when it follows a set of terms, the “example” is merely exemplary and illustrative and should not be considered exclusive or extensive.

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

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

Claims

1. A method for compensating for resistance gradient effects, characterized in that, include: The voltage sampling circuit divides the voltage divider resistors into high-order voltage divider resistors and low-order voltage divider resistors. One end of the high-order voltage divider resistor is connected to the power input terminal, and the other end is connected to the low-order voltage divider resistor. The low-potential end of the low-order voltage divider resistor is connected to the low-order correction resistor. A corresponding switching transistor is connected in parallel across each low-order correction resistor. Both the high-order and low-order voltage divider resistors are three-terminal resistors. The third terminal of the high-order voltage divider resistor is connected to the power supply voltage, and the third terminal of the low-order voltage divider resistor is connected to the sub-potential, which is the lowest potential of the chip. as well as Adjust the number of series resistors in the high-order voltage divider resistor so that the deviation between the total resistance of the high-order and low-order voltage divider resistors and the target value is less than a preset deviation. The target value is the sum of the ideal resistance values ​​of the high-order and low-order voltage divider resistors, where the resistance of the high-order voltage divider resistor is greater than the ideal resistance value and the resistance of the low-order voltage divider resistor is less than the ideal resistance value. Set the minimum correction step size and the step size for each low-order correction resistor; Based on the deviation between the total resistance 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 corresponding switch transistor conduction state is controlled to compensate for the error. This includes: calculating the voltage sampling error based on the deviation between the total resistance of the high-order voltage divider resistor and the low-order voltage divider resistor and the target value; setting the correction code value of each switch transistor based on the voltage sampling error; and controlling the conduction state of the switch transistor based on the correction code value: when the correction code value is 1, the switch transistor is turned on, and the corresponding low-order correction resistor is shorted in the voltage sampling circuit. When the correction code value is 0, the switch is turned off, and the corresponding low-order correction resistor is connected in series in the voltage sampling circuit.

2. The compensation method according to claim 1, characterized in that, The ideal resistance values ​​of the high-position voltage divider resistor and the low-position voltage divider resistor are equal, and they are made of the same material, using the same process and dimensions.

3. The compensation method according to claim 1, characterized in that, The setting of the minimum correction step size and the step size of each low-order correction resistor includes: The minimum correction step size is set according to the deviation range between the estimated total resistance of the high-division and low-division resistors and the target value; Set different step sizes for each low-order correction resistor according to the minimum correction step size; and Remove the maximum correction step size of the low-order correction resistor from the resistance value of the low-order voltage divider resistor.

4. A voltage sampling circuit, characterized in that, include: The system comprises a high-voltage divider resistor, a low-voltage divider resistor, and a low-voltage correction resistor. One end of the high-voltage divider resistor is connected to the power input terminal, and the other end is connected to the low-voltage divider resistor. The low-potential terminal of the low-voltage divider resistor is connected to the low-voltage correction resistor. A corresponding switching transistor is connected in parallel across each low-voltage correction resistor. The number of series resistors in the high-voltage divider resistor and the conduction state of the switching transistor are determined according to the resistance gradient effect compensation method described in any one of claims 1-3.

5. The voltage sampling circuit according to claim 4, characterized in that, The high-position voltage divider resistor and the low-position voltage divider resistor are separated by a preset distance, and each high-position voltage divider resistor and the low-position voltage divider resistor are made of the same material, process and size.

6. The voltage sampling circuit according to claim 4, characterized in that, Both the high-voltage divider resistor and the low-voltage divider resistor are three-terminal resistors. The third terminal of the high-voltage divider resistor is connected to the power supply voltage, and the third terminal of the low-voltage divider resistor is connected to the sub-potential.

7. The voltage sampling circuit according to claim 4, characterized in that, When the switching transistor is turned on, the corresponding low-level correction resistor is shorted in the voltage sampling circuit; when the switching transistor is turned off, the corresponding low-level correction resistor is connected in series in the voltage sampling circuit.

8. A chip, characterized in that, Includes the voltage sampling circuit according to any one of claims 4-7.

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