Compensation circuit and chip

Abstract

This disclosure relates to a compensation circuit and chip, belonging to the field of circuit technology. The compensation circuit includes: a first voltage divider circuit, including a first voltage divider element and a first resistor; a first terminal of the first voltage divider element is connected in series with the first resistor and connected to the input terminal of an error amplifier; the output terminal of the error amplifier is connected to a voltage-controlled oscillator (VCO); and a second voltage divider circuit connected in parallel with the first voltage divider circuit, including a second voltage divider element and a switched capacitor circuit; a second terminal of the second voltage divider element is connected in series with the switched capacitor circuit and connected to the input terminal of the error amplifier; the switching frequency of the switched capacitor circuit is determined according to the frequency of the oscillation signal provided by the VCO; the output voltage of the first terminal and the output voltage of the second terminal are equal; and the temperature drift coefficient corresponding to the ratio of the parameter values ​​of the first and second voltage divider elements has the opposite sign to the temperature drift coefficient of the first resistor. The technical solution of this disclosure improves the temperature stability of the VCO and the flexibility of temperature drift compensation.

Description

Technical Field

[0001] This disclosure relates to the field of circuit technology, and in particular to a compensation circuit and chip. Background Technology

[0002] Resistor-capacitor oscillators (RC oscillators) are widely used on-chip clock sources in integrated circuits. The output frequency of an RC oscillator is determined by the RC time constant formed by the on-chip resistors and capacitors. However, the resistance / capacitance values ​​of the resistors and capacitors are affected by changes in ambient temperature, causing the output frequency of the RC oscillator to drift significantly with temperature. This makes it difficult to meet the high frequency stability requirements of applications such as communication synchronization and high-precision timing.

[0003] Therefore, how to improve the temperature stability of RC oscillators is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] According to some embodiments of this disclosure, a compensation circuit is provided, comprising: a first voltage divider circuit, including a first voltage divider element and a first resistor, wherein a first terminal of the first voltage divider element is connected in series with the first resistor, the first terminal is connected to the input terminal of an error amplifier, and the output terminal of the error amplifier is connected to a voltage-controlled oscillator; a second voltage divider circuit, connected in parallel with the first voltage divider circuit, the second voltage divider circuit including a second voltage divider element and a switched capacitor circuit, wherein a second terminal of the second voltage divider element is connected in series with the switched capacitor circuit, the second terminal is connected to the input terminal of the error amplifier, the switching frequency of the switched capacitor circuit is determined according to the frequency of the oscillation signal provided by the voltage-controlled oscillator, the output voltage of the first terminal and the output voltage of the second terminal are equal, and the temperature drift coefficient corresponding to the ratio of the parameter value of the first voltage divider element to the parameter value of the second voltage divider element has the opposite sign to the temperature drift coefficient of the first resistor.

[0005] In some embodiments, the product of the change in resistance of the first resistor due to temperature drift and the change in the ratio due to temperature drift is a fixed value.

[0006] In some embodiments, the temperature drift coefficient of the first resistor and the temperature drift coefficient of the first voltage divider element are both negative.

[0007] In some embodiments, the temperature drift coefficient of the first voltage divider element is determined based on the temperature drift coefficient of the second voltage divider element and the temperature drift coefficient of the first resistor, wherein the temperature drift coefficient of the second voltage divider element and the temperature drift coefficient of the first resistor are the same.

[0008] In some embodiments, both the first voltage divider element and the second voltage divider element are passive elements; or both the first voltage divider element and the second voltage divider element are active elements.

[0009] In some embodiments, the passive element includes a resistive element, and the active element includes a current source element.

[0010] In some embodiments, the first resistor is a variable resistor.

[0011] In some embodiments, the parameter values ​​of the first voltage divider element when no temperature drift occurs are the same as the parameter values ​​of the second voltage divider element when no temperature drift occurs.

[0012] In some embodiments, the voltage-controlled oscillator is connected to a frequency divider, and the voltage-controlled oscillator provides the switching frequency to the switched capacitor circuit through the frequency divider. The switching frequency is determined based on the frequency of the oscillation signal and the division ratio of the frequency divider.

[0013] According to other embodiments of this disclosure, a chip is provided, including: the compensation circuit described in any of the above embodiments.

[0014] In some embodiments, the chip further includes: an error amplifier, the input of which is connected to the compensation circuit; and a voltage-controlled oscillator, the input of which is connected to the output of the error amplifier.

[0015] In some embodiments, the chip further includes a frequency divider connected to the output of the voltage-controlled oscillator.

[0016] In the above embodiments, by setting two voltage divider circuits in parallel, the first and second voltage divider elements are flexibly selected to satisfy the constraint that the output voltage at the first terminal and the output voltage at the second terminal are equal, and the temperature drift coefficient corresponding to the ratio of the parameter values ​​of the first and second voltage divider elements has the opposite sign to the temperature drift coefficient of the first resistor. In this way, without limiting the type, material, or process of the components, temperature drift compensation can be performed on the frequency of the oscillation signal provided by the voltage-controlled oscillator, which not only improves the temperature stability of the voltage-controlled oscillator but also enhances the flexibility and process compatibility of temperature drift compensation.

[0017] Other features, aspects, and advantages of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0018] Embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that the drawings described below are merely illustrative of some embodiments of this disclosure and are not intended to limit the scope of this disclosure. In the drawings: Figure 1 Schematic diagrams showing some embodiments of the compensation circuit of this disclosure are provided. Figure 2Schematic diagrams of other embodiments of the compensation circuit of this disclosure are shown; It should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not necessarily drawn to actual scale. The same or similar reference numerals are used in the various drawings to denote the same or similar parts. Therefore, once an item is defined in one drawing, it may not be discussed further in subsequent drawings. Detailed Implementation

[0019] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. It should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein.

[0020] This disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully express the scope of this disclosure to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, the composition of materials, numerical expressions and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0021] The terms "first," "second," and similar words used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "containing" mean that the element preceding the word encompasses the element listed after the word, and do not exclude the possibility of encompassing other elements as well. Terms such as "above" and "below" are used only to indicate relative positional relationships, and these relative positional relationships may also change accordingly when the absolute position of the described object changes.

[0022] In this disclosure, when a specific component is described as being located between a first component and a second component, an intermediary component may or may not be present between the specific component and the first or second component. When a specific component is described as connecting to other components, the specific component may be directly connected to the other components without having an intermediary component, or it may not be directly connected to the other components but may have an intermediary component.

[0023] All terms used in this disclosure (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as a dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0024] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0025] In related technologies, resistors with positive and negative temperature drift coefficients are connected in series in a specific ratio to obtain an equivalent resistance, and temperature compensation is achieved by utilizing the mutual cancellation of their temperature drift characteristics.

[0026] However, this approach requires a resistor with a positive temperature drift coefficient to compensate for temperature drift, which limits process compatibility and the freedom of material selection, resulting in low flexibility in temperature drift compensation.

[0027] In view of this, embodiments of the present disclosure provide a compensation circuit that can achieve temperature drift compensation without relying on a resistor with a positive temperature drift coefficient, thereby improving the process compatibility and flexibility of temperature drift compensation. For example, the technical solution of the present disclosure can be implemented through the following embodiments.

[0028] Figure 1 The diagram shows a structural schematic of some embodiments of the compensation circuit of this disclosure.

[0029] like Figure 1 As shown, the compensation circuit 10 may include a first voltage divider circuit 11 and a second voltage divider circuit 12.

[0030] The first voltage divider circuit 11 includes a first voltage divider element 111 and a first resistor Rtrim. The first terminal Q of the first voltage divider element 111 is connected in series with the first resistor Rtrim. The first terminal Q of the first voltage divider element 111 is connected to the input terminal of the error amplifier op. The output terminal of the error amplifier op is connected to the voltage-controlled oscillator (VCO). For example, the input terminal of the error amplifier op can be grounded through a capacitor to filter out high-frequency noise from the capacitor in the switched capacitor circuit 122.

[0031] The second voltage divider circuit 12 is connected in parallel with the first voltage divider circuit 11. The second voltage divider circuit 12 includes a second voltage divider element 121 and a switched capacitor circuit 122. The second terminal P of the second voltage divider element 121 is connected in series with the switched capacitor circuit 122. The second terminal P of the second voltage divider element 121 is connected to the input terminal of the error amplifier op. The switching frequency clk of the switched capacitor circuit 122 is determined according to the frequency of the oscillation signal clkout provided by the voltage-controlled oscillator (VCO).

[0032] For example, the other end of the first voltage divider element 111 that is different from the first terminal Q and the other end of the second voltage divider element 121 that is different from the second terminal P can both be connected to the power supply terminal VDD; or the other end of the first voltage divider element 111 that is different from the first terminal Q and the other end of the second voltage divider element 121 that is different from the second terminal P can both be grounded. Figure 1The diagram schematically shows the case where the other ends of the first voltage divider element 111 and the second voltage divider element 121 are both connected to the power supply terminal VDD.

[0033] The output voltage V at the first terminal Q of the first voltage divider element 111 is... div The output voltage V at the second terminal P of the second voltage divider element 121 f2v They are equal. The temperature drift coefficient corresponding to the ratio of the parameter values ​​of the first voltage divider element 111 and the second voltage divider element 121 has the opposite sign to the temperature drift coefficient of the first resistor Rtrim.

[0034] By V div =V f2v The frequency of the oscillation signal clkout provided by the voltage-controlled oscillator (VCO) can be obtained. Where M1 represents the parameter value of the first voltage divider element 111, M2 represents the parameter value of the second voltage divider element 121, and C represents the capacitance value of the capacitor in the switched capacitor circuit.

[0035] It should be noted that in the above formula For illustrative purposes only, the above formula may differ depending on the type of the selected first voltage divider element 111 and the second voltage divider element 121. Or it could be Further explanation will follow with some examples.

[0036] As can be seen from the above formula, the factors affecting the temperature stability of the oscillation signal frequency include M1 / M2, Rtrim, and C. Since the temperature drift coefficient of a capacitor is usually small, the change in capacitance C due to temperature drift over a large temperature range is much smaller than the change in resistance Rtrim due to temperature drift, and therefore can be ignored. In other words, the main factors affecting the temperature stability of the oscillation signal frequency are M1 / M2 and Rtrim.

[0037] Based on this, the temperature drift coefficient (also known as the equivalent temperature drift coefficient) corresponding to the ratio M1 / M2 of the parameter values ​​of the first voltage divider element 111 and the second voltage divider element 121 has the opposite sign to the temperature drift coefficient of the first resistor Rtrim. This means that the temperature drift trend of this ratio is opposite to the temperature drift trend of the resistance value of the first resistor Rtrim. Therefore, the change in the resistance value of the first resistor Rtrim due to temperature drift can be compensated by the change in this ratio due to temperature drift, thereby enabling the adjustment of the oscillation signal frequency. Perform temperature drift compensation.

[0038] The "temperature drift coefficient" described in this disclosure represents the relative change of a relevant physical quantity (e.g., resistance) within a unit temperature. A negative temperature drift coefficient indicates that the relevant physical quantity is inversely correlated with temperature (e.g., decreases as temperature increases); a positive temperature drift coefficient indicates that the relevant physical quantity is positively correlated with temperature (e.g., increases as temperature increases). For example, the unit of the temperature drift coefficient can be ppm / ℃, representing the parts per million change in the relevant physical quantity for every 1 degree Celsius change in temperature.

[0039] In some cases, the temperature drift coefficient of the first resistor Rtrim is negative, and the temperature drift coefficient corresponding to this ratio is positive.

[0040] Taking the ratio M1 / M2 as an example, for instance, the temperature drift coefficients of both the first voltage divider element 111 and the second voltage divider element 121 can be selected to be negative, and the absolute value of the temperature drift coefficient of the first voltage divider element 111 is less than the absolute value of the temperature drift coefficient of the second voltage divider element 121 (for example, the temperature drift coefficient of the first voltage divider element 111 is -200ppm / °C, and the temperature drift coefficient of the second voltage divider element 121 is -300ppm / °C). Thus, within the same temperature range, the temperature drift of the first voltage divider element 111 (the numerator) is less than the temperature drift of the second voltage divider element 121 (the denominator). Consequently, the change in this ratio due to temperature drift increases with increasing temperature, exhibiting a positive temperature drift coefficient characteristic. Therefore, by selecting two elements with negative temperature drift coefficients, the temperature drift coefficient corresponding to this ratio can be made positive, thereby achieving temperature drift compensation.

[0041] For example, the temperature drift coefficient of the first voltage divider element 111 can be selected to be positive, and the temperature drift coefficient of the second voltage divider element 121 can be selected to be negative. In this way, the change in the ratio due to temperature drift increases with the increase of temperature, exhibiting a positive temperature drift coefficient characteristic. Thus, by selecting an element with a positive temperature drift coefficient and an element with a negative temperature drift coefficient, the temperature drift coefficient corresponding to the ratio can be made positive, thereby achieving temperature drift compensation.

[0042] In some cases, the temperature drift coefficient of the first resistor Rtrim is positive, and the temperature drift coefficient corresponding to this ratio is negative.

[0043] Taking the ratio M1 / M2 as an example, the temperature drift coefficients of both the first voltage divider element 111 and the second voltage divider element 121 can be selected to be negative, and the absolute value of the temperature drift coefficient of the first voltage divider element 111 is greater than the absolute value of the temperature drift coefficient of the second voltage divider element 121 (for example, the temperature drift coefficient of the first voltage divider element 111 is -300ppm / °C, and the temperature drift coefficient of the second voltage divider element 121 is -200ppm / °C). Thus, within the same temperature range, the temperature drift of the first voltage divider element 111 (the numerator) is greater than the temperature drift of the second voltage divider element 121 (the denominator). Consequently, the change in this ratio due to temperature drift decreases as the temperature increases, exhibiting a negative temperature drift coefficient characteristic. Therefore, by selecting two elements with negative temperature drift coefficients, the temperature drift coefficient corresponding to this ratio can be made negative, thereby achieving temperature drift compensation.

[0044] For example, the temperature drift coefficients of both the first voltage divider element 111 and the second voltage divider element 121 can be selected to be positive, and the absolute value of the temperature drift coefficient of the first voltage divider element 111 can be smaller than the absolute value of the temperature drift coefficient of the second voltage divider element 121 (for example, the temperature drift coefficient of the first voltage divider element 111 is 200 ppm / °C, and the temperature drift coefficient of the second voltage divider element 121 is 300 ppm / °C). In this way, within the same temperature range, the temperature drift of the first voltage divider element 111 (the numerator) is smaller than the temperature drift of the second voltage divider element 121 (the denominator), and thus the change in this ratio due to temperature drift decreases as the temperature increases, exhibiting a negative temperature drift coefficient characteristic. Therefore, by selecting two elements with both positive temperature drift coefficients, it is also possible to make the temperature drift coefficient corresponding to this ratio negative, thereby achieving temperature drift compensation.

[0045] For example, the temperature drift coefficient of the first voltage divider element 111 can be selected to be negative, and the temperature drift coefficient of the second voltage divider element 121 can be selected to be positive. In this way, the change in the ratio due to temperature drift decreases as the temperature increases, exhibiting a negative temperature drift coefficient characteristic. Thus, by selecting an element with a positive temperature drift coefficient and an element with a negative temperature drift coefficient, the temperature drift coefficient corresponding to the ratio can be made negative, thereby achieving temperature drift compensation.

[0046] It is evident that temperature drift compensation does not necessarily depend on components with a positive temperature drift coefficient. By rationally configuring the temperature drift coefficients of the components serving as the numerator and denominator in the voltage divider circuit, so that the ratio exhibits an equivalent temperature drift characteristic with the opposite sign to the temperature drift coefficient of the first resistor, the effect of temperature drift compensation can be achieved.

[0047] In the above embodiments, by setting two voltage divider circuits in parallel, the first voltage divider element 111 and the second voltage divider element 121 are flexibly selected to satisfy V div =V f2vThis constraint ensures that the temperature drift coefficient corresponding to the ratio of the parameter values ​​of the first voltage divider element 111 and the second voltage divider element 121 has the opposite sign to the temperature drift coefficient of the first resistor Rtrim. Thus, without limiting the type, material, or manufacturing process of the components, it is possible to control the oscillation signal frequency. Temperature drift compensation not only improves the temperature stability of the voltage-controlled oscillator, but also enhances the flexibility and process compatibility of temperature drift compensation.

[0048] The selection of the first voltage divider element 111 and the second voltage divider element 121 will be further described below with reference to some embodiments.

[0049] In some embodiments, the product of the change in resistance of the first resistor Rtrim due to temperature drift and the ratio of the parameter values ​​of the first voltage divider element 111 and the second voltage divider element 121 due to temperature drift is a fixed value.

[0050] For example, as analyzed earlier, the frequency of the oscillation signal clkout For every 1 degree Celsius change in temperature, Changes and The product of the changes is a fixed value (e.g., 1), making the frequency... The value is unaffected by temperature. Thus, by flexibly selecting the first voltage divider element 111 and the second voltage divider element 121 to ensure that the product is a fixed value, the temperature stability of the frequency can be further improved while enhancing the flexibility of temperature drift compensation.

[0051] In some embodiments, the temperature drift coefficient of the first resistor Rtrim is negative, and at least one of the temperature drift coefficients of the first voltage divider element 111 and the second voltage divider element 121 is negative. For example, the temperature drift coefficients of the first resistor Rtrim, the first voltage divider element 122, and the second voltage divider element 121 can all be negative. For example, referring to the previous embodiments, in order to make the temperature drift trend corresponding to the ratio of the parameter values ​​of the two voltage divider elements opposite to the temperature drift trend of the resistance value of the first resistor Rtrim, the temperature drift coefficients of the first voltage divider element 122 and the second voltage divider element 121 can both be selected to be negative.

[0052] Considering that components with negative temperature drift coefficients are cheaper to manufacture than those with positive temperature drift coefficients, and that components with negative temperature drift coefficients are less affected by process deviations in terms of accuracy than those with positive temperature drift coefficients, this approach allows for the uniform use of components with negative temperature drift coefficients for temperature drift compensation, eliminating the need for any components with positive temperature drift coefficients. This enables accurate and flexible temperature drift compensation at a low cost.

[0053] In some embodiments, the temperature drift coefficient of the first voltage divider element 111 is determined based on the temperature drift coefficient of the second voltage divider element 121 and the temperature drift coefficient of the first resistor Rtrim, wherein the temperature drift coefficient of the second voltage divider element 121 and the temperature drift coefficient of the first resistor Rtrim are the same.

[0054] For example, for every 1 degree Celsius change in temperature, Changes and The product of the changes is a fixed value (e.g., 1). The temperature drift coefficient of the first voltage divider element 111 can be calculated based on the temperature drift coefficient of the second voltage divider element 121 and the temperature drift coefficient of the first resistor Rtrim.

[0055] Based on this, the temperature drift coefficient of the second voltage divider element 121 is selected to be the same as that of the first resistor Rtrim. This reduces the complex trade-off of independently selecting three elements with different temperature drift coefficients, reduces the degree of freedom from three-parameter optimization to single-parameter design, simplifies the design constraints and reduces the implementation complexity of temperature drift compensation, thereby helping to achieve flexible temperature drift compensation in a low-cost manner.

[0056] In some embodiments, the first voltage divider element 111 and the second voltage divider element 121 are both passive elements; or the first voltage divider element and the second voltage divider element 121 are both active elements.

[0057] For example, passive components may include resistive components, and active components may include current source components. That is, the first voltage divider 111 and the second voltage divider 121 may both be resistive components, or the first voltage divider 111 and the second voltage divider 121 may both be current source components.

[0058] Figure 1 The diagram schematically illustrates the case where both the first voltage divider element 111 and the second voltage divider element 121 are resistive elements.

[0059] exist Figure 1 In the example shown, the output voltage of the first terminal Q The output voltage of the second terminal P , by V div =V f2v The frequency of the oscillation signal clkout can be obtained. Where R1 represents the resistance of the first voltage divider element 111, R2 represents the resistance of the second voltage divider element 121, C represents the capacitance of the capacitor in the switched capacitor circuit, and f1 is the frequency value of the switching frequency clk of the switched capacitor.

[0060] Therefore, the change in resistance of the first resistor Rtrim due to temperature drift can be compensated by the change in ratio due to temperature drift, which is the ratio of the resistances of the first voltage divider element 111 and the second voltage divider element 121. The amount of change caused by temperature drift.

[0061] Figure 2 Schematic diagrams of other embodiments of the compensation circuit of this disclosure are shown. Figure 2 The diagram schematically illustrates the case where both the first voltage divider element 111 and the second voltage divider element 121 are current source elements.

[0062] exist Figure 2 In the example shown, in the compensation circuit 20, the output voltage of the first terminal Q is... The output voltage of the second terminal P , by V div =V f2v The frequency of the oscillation signal clkout can be obtained. ,in, This indicates the current value of the first voltage divider element 111. The value of f1 represents the current of the second voltage divider element 121, C represents the capacitance of the capacitor in the switched capacitor circuit, and f1 is the frequency of the switching capacitor clk.

[0063] Therefore, the change in resistance of the first resistor Rtrim due to temperature drift can be compensated by the change in ratio due to temperature drift, which is the ratio of the current values ​​of the first voltage divider element 111 and the second voltage divider element 121. The amount of change caused by temperature drift.

[0064] It can be seen that the selection of the first voltage divider element 111 and the second voltage divider element 121 is no longer limited to a single device type. Both resistive elements can be used to construct a passive voltage divider architecture, and current source elements can be used to construct an active voltage divider architecture, thereby improving the flexibility and process compatibility of temperature drift compensation.

[0065] In some embodiments, the first resistor Rtrim is a variable resistor. For example, frequency calibration can be performed by adjusting the resistance value of the first resistor Rtrim.

[0066] Considering that frequency calibration and temperature compensation are coupled in the relevant technology, once the resistance value of the first resistor Rtrim is changed to calibrate the frequency, the original series resistor ratio is destroyed, and the series resistor ratio needs to be readjusted to maintain the effect of temperature drift compensation.

[0067] In this embodiment, the first resistor Rtrim is set as a variable resistor. Adjusting the resistance of Rtrim does not change its temperature drift coefficient, thus decoupling frequency calibration from temperature drift compensation. This prevents interference with the temperature compensation scheme during frequency calibration, reducing the risk of compensation failure and improving the effectiveness of temperature compensation, thereby enhancing the temperature stability of the voltage-controlled oscillator.

[0068] In some embodiments, the parameter values ​​of the first voltage divider element 111 when no temperature drift occurs are the same as the parameter values ​​of the second voltage divider element 121 when no temperature drift occurs.

[0069] For example, in Figure 1 In the example shown, both the first voltage divider element 111 and the second voltage divider element 121 are resistive elements, and the resistance R1 of the first voltage divider element 111 and the resistance R2 of the second voltage divider element 121 are the same without temperature drift. For example, in Figure 2 In the example shown, both the first voltage divider element 111 and the second voltage divider element 121 are current source elements, and the current value of the first voltage divider element 111 is... The current value of the second voltage divider element 121 The same applies if no temperature drift occurs.

[0070] Therefore, regardless of whether both are resistive elements or both are current source elements, the frequency of the oscillation signal clkout remains the same. It can be seen that, without temperature drift, the frequency The value is determined by Rtrim and C; the setting of the voltage divider element does not affect the frequency. The setting, frequency The baseline value is determined by the product of Rtrim and C.

[0071] In some embodiments, such as Figure 1 or Figure 2 As shown, the voltage-controlled oscillator (VCO) can be connected to the frequency divider (DIV). The VCO can provide a switching frequency (clk) to the switched capacitor circuit 122 via the frequency divider (DIV). The switching frequency (clk) is determined based on the frequency of the oscillation signal (clkout) and the division ratio of the frequency divider (DIV). For example, this compensation circuit can be an oscillator circuit (OSC) for temperature drift compensation. At different OSC oscillation frequencies, by setting the division ratio of the frequency divider (DIV), the switching frequency (clk) provided to the switched capacitor circuit 122 is adjusted, thereby making the equivalent resistance of the switched capacitor circuit 122 close to the resistance of the first resistor (Rtrim). Compared to not using the frequency divider (DIV), this reduces the occurrence of situations where the capacitance of capacitor C is small due to a high oscillation frequency, or large due to a low oscillation frequency. Moreover, by using the frequency divider (DIV), the frequency range of the OSC circuit output can be extended, for example, to achieve a frequency multiplication function.

[0072] In this way, by setting the division ratio of the frequency divider, the equivalent resistance of the switched capacitor circuit can be flexibly adjusted, so that the oscillation signal output by the voltage-controlled oscillator (VCO) operates at the target frequency, thereby expanding the frequency adjustment range and helping to broaden the application scenarios of the circuit.

[0073] This disclosure also provides a chip that includes a compensation circuit (e.g., compensation circuit 10 / 20) from any of the above embodiments.

[0074] In some embodiments, the chip may also include an error amplifier (e.g., error amplifier op) and a voltage-controlled oscillator (e.g., voltage-controlled oscillator VCO).

[0075] For example, the input of the error amplifier is connected to the compensation circuit, and the input of the voltage-controlled oscillator is connected to the output of the error amplifier.

[0076] In some embodiments, the chip may further include a frequency divider connected to the output of the voltage-controlled oscillator (VCO). For example, the VCO provides a switching frequency clk to the switched capacitor circuit 122 via the frequency divider DIV, the switching frequency clk being determined based on the frequency of the oscillation signal and the division ratio of the frequency divider DIV.

[0077] In some embodiments, the chip can be applied to the field of light sensing, such as an ambient light sensor chip or an image sensor chip. For example, the compensation circuit can be an oscillator circuit (e.g., an OSC circuit) for temperature drift compensation. The compensation circuit can serve as an on-chip clock source for the ambient light sensor chip or image sensor chip, providing a reference clock signal for analog-to-digital conversion, digital signal processing, and communication interfaces.

[0078] In some embodiments, the chip can be applied in the field of driver chips, such as motor driver chips and display driver chips. The compensation circuit can serve as an on-chip clock source for the motor driver chip and display driver chip, providing a reference clock signal for timing control, etc.

[0079] In some embodiments, the chip can be applied in the audio field; for example, the chip may include an audio codec chip or a microphone array processor chip. The compensation circuit can serve as a clock reference for the audio codec chip or the microphone array processor chip to improve the accuracy of the audio sampling rate.

[0080] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0081] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A compensation circuit, comprising: The first voltage divider circuit includes a first voltage divider element and a first resistor. The first terminal of the first voltage divider element is connected in series with the first resistor. The first terminal is connected to the input terminal of the error amplifier. The output terminal of the error amplifier is connected to the voltage-controlled oscillator. A second voltage divider circuit is connected in parallel with the first voltage divider circuit. The second voltage divider circuit includes a second voltage divider element and a switched capacitor circuit. The second terminal of the second voltage divider element is connected in series with the switched capacitor circuit, and the second terminal is connected to the input terminal of the error amplifier. The switching frequency of the switched capacitor circuit is determined according to the frequency of the oscillation signal provided by the voltage-controlled oscillator. The output voltage of the first terminal is equal to the output voltage of the second terminal, and the temperature drift coefficient corresponding to the ratio of the parameter value of the first voltage divider element to the parameter value of the second voltage divider element has the opposite sign to the temperature drift coefficient of the first resistor.

2. The compensation circuit according to claim 1, wherein, The product of the change in resistance of the first resistor due to temperature drift and the change in the ratio due to temperature drift is a fixed value.

3. The compensation circuit according to claim 2, wherein, The temperature drift coefficient of the first resistor is negative, and at least one of the temperature drift coefficients of the first voltage divider element and the second voltage divider element is negative.

4. The compensation circuit according to claim 2, wherein, The temperature drift coefficient of the first voltage divider element is determined based on the temperature drift coefficient of the second voltage divider element and the temperature drift coefficient of the first resistor. The temperature drift coefficient of the second voltage divider element is the same as that of the first resistor.

5. The compensation circuit according to any one of claims 1-4, wherein: Both the first voltage divider element and the second voltage divider element are passive components; or Both the first voltage divider element and the second voltage divider element are active elements.

6. The compensation circuit according to claim 5, wherein, The passive element includes a resistive element, and the active element includes a current source element.

7. The compensation circuit according to any one of claims 1-4, wherein, The first resistor is a variable resistor.

8. The compensation circuit according to any one of claims 1-4, wherein, The parameter values ​​of the first voltage divider element when no temperature drift occurs are the same as those of the second voltage divider element when no temperature drift occurs.

9. The compensation circuit according to any one of claims 1-4, wherein, The voltage-controlled oscillator is connected to a frequency divider, and the voltage-controlled oscillator provides the switching frequency to the switched capacitor circuit through the frequency divider. The switching frequency is determined based on the frequency of the oscillation signal and the division ratio of the frequency divider.

10. A chip, comprising: The compensation circuit according to any one of claims 1-9.

11. The chip according to claim 10, further comprising: An error amplifier, the input of which is connected to the compensation circuit; A voltage-controlled oscillator, wherein the input terminal of the voltage-controlled oscillator is connected to the output terminal of the error amplifier.

12. The chip according to claim 11, further comprising: A frequency divider is connected to the output of the voltage-controlled oscillator.

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