Compensation circuit of resistance voltage division circuit

Abstract

The invention discloses a compensating circuit of a resistance voltage division circuit, which is characterized in that the resistance voltage division circuit adopts a resistance voltage division mode to convert a signal to be measured into a voltage division signal, and the voltage division signal is output by a voltage division node; the compensation circuit comprises a voltage division proportion compensation module which is connected with the voltage division node and is used for selectively carrying out voltage division proportion compensation on the voltage division signal according to the voltage value of the signal to be detected, so that the output precision of the voltage division signal can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to a compensation circuit of a resistor voltage divider circuit. Background Art

[0002] When sampling a voltage signal in the prior art, it is usually necessary to divide the voltage signal through a voltage divider circuit so that its voltage value is within a reasonable ADC (Analog to Digital Converter) input range, and then convert the divided voltage into a digital value through the ADC.

[0003] Figure 1 FIG. 1 shows a circuit diagram of a voltage divider circuit according to the prior art. Figure 1 The voltage divider circuit adopts a resistor voltage divider, which includes a resistor connected in series with the waiting side signal V BUS N (N>1) resistors R with equal resistance between the ground terminal and the second to last resistor R and the first to last resistor R provide a voltage division signal V D , the voltage division signal V D =V BUS / N. Voltage division signal V D It is input to the ADC for sampling, and the final result is multiplied by N through the digital processor to obtain the measured signal V BUS The sampling value of the signal to be measured is usually V BUS The sampling accuracy is mainly limited by the ADC accuracy, but for high voltage signals (such as the V BUS Input, V of BUCK charging chip BUS In addition to being affected by the ADC accuracy, the sampling accuracy is also affected by the different voltage differences of each voltage divider resistor to the substrate voltage, and the voltage divider ratio itself will also produce a certain error, and the measured signal V BUS The higher the voltage, the greater the error.

[0004] Figure 2 FIG. 1 shows a schematic diagram of a resistor structure according to the prior art. Figure 2 The actual resistance R is the positive electrode (V pos ), negative electrode (V neg ), substrate (V sub )three-terminal, the resistance value of the resistor R is related to the positive and negative poles of the resistor (V pos , V neg ) to substrate (V sub ) voltage difference (V rtosub ) shows a first-order characteristic and can be approximately expressed as:

[0005] R≈r0(1-K1V rtosub )(1)

[0006] V rtosub =(V pos +V neg ) / 2-V sub (2)

[0007] Among them, V rtosub For the positive and negative poles of the resistor (V pos , V neg ) Average voltage to substrate (V sub ), r0 is V rtosub The resistance impedance when is 0, K1 is the coefficient of the resistance formula.

[0008] Figure 3 Shows the use of Figure 2 The schematic diagram of the structure of the resistor voltage divider circuit composed of the resistors shown in FIG. Figure 3 The resistor divider circuit includes a resistor connected in series with the waiting side signal V BUS The voltage divider resistor R between the ground terminal d2 and R d1 , voltage divider resistor R d1 and R d2 The middle node provides a voltage-divided signal V D . Voltage divider resistor R d1 It includes a resistor R and a voltage divider resistor R d2 It includes (N-1) resistors R connected in series. The voltage divider resistor R d1 It can be expressed as:

[0009] R d1 ≈r0(1-K1V rtosub1 )(3)

[0010] Voltage divider resistor R d2 It can be expressed as:

[0011] R d2 ≈(N-1)r0(1-K1V rtosub2 )(4)

[0012] Among them, V rtosub1 Represents the voltage divider resistor R d1 Average voltage of positive and negative electrodes to substrate voltage V sub The voltage difference, V rtosub2 Represents the voltage divider resistor R d2 Average voltage of positive and negative electrodes to substrate voltage V sub The voltage difference, V rtosub1 and V rtosub2 It can be expressed as:

[0013] V rtosub1 =V D / 2≈0(5)

[0014] V rtosub2 =(V BUS +V D ) / 2≈V BUS / 2 (6)

[0015] From formulas (5) and (6), we can see that when the measured signal V BUS When the voltage value of is high and the value of N is large, V rtosub2 Much larger than V rtosub1 , therefore, V rtosub1 The influence on sampling accuracy can be ignored. By Taylor transforming and approximating the formula, the simplified voltage divider ratio ratio, V D / V BUS As shown in formula (7), K n is the coefficient of the voltage divider ratio formula.

[0016] (7)

[0017] It can be seen from formula (7) that the voltage division ratio is related to the measured signal V BUS There is a second-order relationship between them. As the measured signal V BUS As the voltage value increases, the voltage divider signal V D The greater the deviation from the expected value, the Figure 3 The resistor voltage divider circuit shown divides the high voltage signal, and the output voltage division result will produce a certain error, thereby affecting the system conversion accuracy of the ADC.

[0018] The ideal voltage division ratio of the resistor voltage divider circuit is one in N. The error of the actual voltage division ratio is error (‰) = 1000*(actual voltage division ratio - ideal voltage division ratio)*N. Take N=10 as an example, see Figure 4 , the error of the actual voltage division ratio follows the measured signal V BUS increases with the increase of the measured signal V BUS =20V, the actual voltage division ratio will produce an error of about 2.4124‰.

[0019] Therefore, a new resistor voltage divider circuit is needed to achieve higher precision voltage sampling. Summary of the invention

[0020] In view of the above problems, an object of the present invention is to provide a compensation circuit for a resistor voltage divider circuit, thereby improving the output accuracy of a voltage divider signal.

[0021] According to one aspect of the present invention, a compensation circuit for a resistor voltage divider circuit is provided, wherein the resistor voltage divider circuit converts a signal to be measured into a voltage divided signal by means of resistor voltage division, and outputs the voltage divided signal from a voltage dividing node; the compensation circuit comprises a voltage dividing ratio compensation module, which is connected to the voltage dividing node and is used to selectively perform voltage dividing ratio compensation on the voltage divided signal according to the voltage value of the signal to be measured.

[0022] Optionally, the voltage divider ratio compensation module does not perform voltage divider ratio compensation on the voltage divider signal when the voltage value of the signal to be measured is less than a first threshold voltage, and performs voltage divider ratio compensation on the voltage divider signal according to the voltage value of the signal to be measured when the voltage value of the signal to be measured is greater than / equal to the first threshold voltage.

[0023] Optionally, the voltage divider ratio compensation module includes a control unit, which converts the measured signal into a control signal by means of resistance voltage division; and a compensation unit, which is used to selectively extract a voltage divider ratio compensation current from the voltage divider node according to the control signal, so as to selectively perform voltage divider ratio compensation on the voltage divider signal.

[0024] Optionally, the voltage value of the control signal is smaller than the voltage value of the voltage-divided signal.

[0025] Optionally, when the voltage value of the signal to be measured is less than the first threshold voltage, the compensation unit does not extract the voltage divider ratio compensation current from the voltage divider node; when the voltage value of the signal to be measured is greater than / equal to the first threshold voltage, the compensation unit extracts the voltage divider ratio compensation current from the voltage divider node, and when the voltage value of the signal to be measured is greater than / equal to the first threshold voltage and less than a second threshold voltage, the voltage divider ratio compensation current is made to have an exponential relationship with the control signal, and when the voltage value of the signal to be measured is greater than / equal to the second threshold voltage, the voltage divider ratio compensation current is made to have a linear relationship with the control signal.

[0026] Optionally, the compensation circuit also includes a temperature compensation module, which is connected to the voltage division ratio compensation module and is used to generate a temperature compensation current, and input the temperature compensation current to the voltage division ratio compensation module to adjust the current value of the voltage division ratio compensation current.

[0027] Optionally, the control unit includes a first voltage-dividing resistor and a second voltage-dividing resistor, which are sequentially connected between the voltage to be measured and a ground terminal, and an intermediate node between the first voltage-dividing resistor and the second voltage-dividing resistor provides the control signal.

[0028] Optionally, the compensation unit includes a first transistor and a first resistor, which are sequentially connected between the voltage dividing node and the ground terminal, the control terminal of the first transistor receives the control signal, and the voltage dividing ratio compensation current flows through the first transistor and the first resistor.

[0029] Optionally, the temperature compensation module includes a second resistor and a second transistor, which are connected between a power supply voltage and an intermediate node between the first transistor and the first resistor in sequence, the control end of the second transistor receives a reference voltage, and the temperature compensation current flows through the second resistor and the second transistor.

[0030] Optionally, the first transistor and the second transistor are NMOS transistors.

[0031] The compensation circuit of the resistor voltage divider circuit provided by the present invention can improve the output accuracy of the voltage divider signal by selectively performing voltage divider ratio compensation on the voltage divider signal according to the voltage value of the signal to be measured through the voltage divider ratio compensation module.

[0032] In a preferred embodiment, the compensation circuit further performs temperature compensation on the voltage division signal through a temperature compensation module, so that the resistance voltage division ratio curves can be closer at different temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0034] Figure 1 A circuit diagram of a voltage divider circuit according to the prior art is shown;

[0035] Figure 2 A schematic diagram of the structure of a resistor according to the prior art is shown;

[0036] Figure 3 Shows the use of Figure 2 A schematic diagram of a resistor voltage divider circuit composed of resistors shown in FIG.

[0037] Figure 4 Shows Figure 3 The error simulation diagram of the resistor voltage divider circuit shown;

[0038] Figure 5 A circuit diagram of a resistor voltage divider circuit and a compensation circuit thereof according to a first embodiment of the present invention is shown;

[0039] Figure 6 A schematic diagram showing the relationship between the voltage division ratio compensation current and the control signal of the compensation circuit according to the first embodiment of the present invention is shown;

[0040] Figure 7A schematic diagram showing a comparison between a voltage-divided signal after compensation by the compensation circuit of the first embodiment of the present invention and a voltage-divided signal of the prior art;

[0041] Figure 8 shows a schematic diagram of simulation of the voltage division signal provided by the first embodiment of the present invention at different temperatures;

[0042] Fig. 9 A circuit diagram of a resistor voltage divider circuit and a compensation circuit thereof according to a second embodiment of the present invention is shown;

[0043] Fig.10 FIG. 4 is a schematic diagram showing a simulation of a voltage division signal provided by the second embodiment of the present invention at different temperatures. DETAILED DESCRIPTION

[0044] Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, the same elements or modules are represented by the same or similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale.

[0045] It should be understood that in the following description, a "circuit" may include a single or multiple combined hardware circuits, programmable circuits, state machine circuits, and / or elements capable of storing instructions executed by programmable circuits. When an element or circuit is said to be "connected to" another element or an element or circuit is said to be "connected between" two nodes, it may be directly coupled or connected to another element or there may be an intermediate element, and the connection between the elements may be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there is no intermediate element between the two.

[0046] At the same time, certain words are used in this patent specification and claims to refer to specific components. It should be understood by those skilled in the art that hardware manufacturers may use different terms to refer to the same component. This patent specification and claims do not use differences in names as a way to distinguish components, but rather use differences in components' functions as the criteria for distinction.

[0047] In addition, it should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the statement "comprise one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements.

[0048] Figure 5 A circuit diagram of a resistor voltage divider circuit and a compensation circuit thereof according to a first embodiment of the present invention is shown.

[0049] See also Figure 5 The compensation circuit of the resistor voltage divider circuit 100 includes a voltage divider ratio compensation module 210. The resistor voltage divider circuit 100 uses a resistor voltage divider to convert the waiting side signal V BUS Converted into a voltage-divided signal V D , and the voltage division node outputs the voltage division signal V D The voltage division ratio compensation module 210 is used to calculate the voltage of the measured signal V BUS The voltage value selectively divides the voltage signal V D Perform voltage division ratio compensation to make the voltage division signal V D is closer to the ideal value. Specifically, when the measured signal V BUS When the voltage value of the measured signal V is less than the first threshold voltage, the voltage division ratio compensation module 210 does not BUS To compensate the voltage divider ratio, when the measured signal V BUS When the voltage value of the measured signal V is greater than / equal to the first threshold voltage, the voltage division ratio compensation module 210 BUS The voltage value of the voltage divided signal V D Perform voltage division ratio compensation.

[0050] The voltage division ratio compensation module 210 includes a control unit 211 and a compensation unit 212. The control unit 211 uses a resistor voltage division method to convert the waiting side signal V BUS is converted into a control signal Vc, the voltage value of the control signal Vc is less than the voltage division signal V D The compensation unit 212 is used to selectively extract the voltage division ratio compensation current I2 from the voltage division node according to the control signal Vc to compensate the voltage division signal V D Specifically, when the measured signal V BUSWhen the voltage value of the measured signal V is less than the first threshold voltage, the compensation unit 212 does not BUS The voltage division ratio compensation is performed, that is, the voltage division ratio compensation current I2 is not drawn from the voltage division node. When the measured signal V BUS When the voltage value of the measured signal V BUS To perform voltage division ratio compensation, the voltage division ratio compensation current I2 is extracted from the voltage division node and the voltage division ratio compensation current I2 is added to the measured signal V BUS When the voltage value of the measured signal V is greater than / equal to the first threshold voltage and less than the second threshold voltage, the voltage-dividing ratio compensation current I2 is exponentially related to the control signal Vc. BUS When the voltage value of is greater than / equal to the second threshold voltage, the voltage-dividing ratio compensation current I2 is linearly related to the control signal Vc. The second threshold voltage is greater than the first threshold voltage.

[0051] The resistor voltage divider circuit 100 includes a resistor connected to the test signal V BUS The voltage divider resistor R between the ground terminal d2 and R d1 , voltage divider resistor R d2 and R d1 The middle node is used as a voltage divider node to provide a voltage divider signal V D , current I flows through the voltage divider resistor R d2 , current I1 flows through the voltage divider resistor R d1 , voltage divider resistor R d2 and R d1 The substrate is connected to the ground terminal GND. For example, the voltage divider resistor R d1 Including resistor R, voltage divider resistor R d2 The circuit comprises a plurality of resistors R connected in series, wherein the substrate of the resistor R is connected to the ground terminal GND. d1 The resistance value can be expressed as R d1 =1*R, voltage divider resistor R d2 The resistance value can be expressed as R d2 =(N Rd -1)*R, where N Rd represents the number of resistors R in the resistor voltage divider circuit 100 , and R represents the resistance value of the resistor R.

[0052] The control unit 211 includes a BUS The voltage divider resistor R between the ground terminal c2 and R c1 , voltage divider resistor R c1 and R c2 The middle node provides the control signal Vc, and the voltage divider resistor R c2 and R c1 The substrate is connected to the ground terminal GND. For example, the voltage divider resistor Rc1 Including resistor R, voltage divider resistor R c2 It includes multiple resistors R connected in series, a voltage divider resistor R c1 The resistance value can be expressed as R c1 =1*R, voltage divider resistor R c2 The resistance value can be expressed as R c2 =(N Rc -1)*R, where N Rc Represents the voltage divider resistor R c1 The number of resistors R and the voltage divider resistor R c2 The sum of the number of resistors R in the circuit, R represents the resistance value of resistor R, N Rc Greater than N Rd .

[0053] The compensation unit 212 includes a transistor M1 and a resistor R1 which are sequentially connected between the voltage dividing node and the ground terminal. The control terminal of the transistor M1 is connected to the voltage dividing resistor R c1 and R c2 The voltage-dividing ratio compensation current I2 flows through the transistor M1 and the resistor R1. The resistance value of the resistor R1 is relatively large, which is greater than the resistance value of the resistor R.

[0054] Figure 6 A schematic diagram showing the relationship between the voltage division ratio compensation current and the control signal of the compensation circuit according to the first embodiment of the present invention is shown.

[0055] Combined with the following figure Figure 5 and Figure 6 The working principle of the voltage division ratio compensation module 210 is described below. Figure 5 and Figure 6 , when the measured signal V BUS When the voltage value of is small, the second-order coefficient has little influence on the accuracy, the voltage value of the control signal Vc is low, and the transistor M1 is turned off. At this time, the compensation unit 212 does not extract the voltage-dividing ratio compensation current I2 from the voltage-dividing node, and the current I1 in the resistor voltage-dividing circuit 100 is equal to the current I; as the measured signal V BUS As the voltage value of increases, the second-order coefficient gradually begins to affect the voltage division ratio. When the voltage value of the control signal Vc is greater than / equal to the first threshold voltage (the first threshold voltage is close to the threshold voltage Vth of the transistor M1, which is the voltage that can just make the transistor M1 work in the subthreshold region) and less than the second threshold voltage (the second threshold voltage refers to the threshold voltage Vth of the transistor M1), the transistor M1 works in the subthreshold region, and the compensation unit 212 extracts the voltage division ratio compensation current I2 from the voltage division node (because the control signal Vc also has a second-order coefficient, the actual extracted I2 is a second-order current), so that I=I1+I2. At this time, the voltage division ratio compensation current I2 is exponentially related to the control signal Vc. When the measured signal V BUSAfter continuing to increase to the second threshold voltage, i.e., the threshold voltage Vth of the transistor M1, the transistor M1 enters the saturation region, and the compensation unit 212 extracts the voltage-dividing ratio compensation current I2 from the voltage-dividing node, so that I=I1+I2. At this time, due to the existence of source negative feedback, the voltage-dividing ratio compensation current I2 presents a linear relationship with the control signal Vc.

[0056] When transistor M1 operates in the subthreshold region, the voltage division ratio can be expressed as:

[0057] ,

[0058] Among them, K n1 is the coefficient of the resistance voltage divider ratio formula in the resistance voltage divider circuit 100, and a is the coefficient of the subthreshold region exponential current formula;

[0059] The voltage division ratio compensation current I2 can be expressed as:

[0060] I2≈a*e Vc .

[0061] When transistor M1 works in the saturation region, the voltage division ratio can be expressed as:

[0062]

[0063] Among them, K n2 is the coefficient of the resistance voltage division ratio formula in the control unit 211;

[0064] The voltage division ratio compensation current I2 can be expressed as:

[0065] I2≈1 / R1*b*(Vc-Vx-Vth),

[0066] Wherein, Vx refers to the intermediate node voltage between transistor M1 and resistor R1, and b is the coefficient of the linear current formula in the saturation region.

[0067] Optionally, by adjusting the coefficients and the voltage division ratio compensation current I2, the voltage division signal V D Optimal compensation.

[0068] Figure 7 A schematic diagram comparing a voltage-divided signal compensated by the compensation circuit of the first embodiment of the present invention and a voltage-divided signal of the prior art is shown.

[0069] See also Figure 7 In the prior art, the voltage division signal V D The voltage division ratio ratio changes with the measured signal V BUS In this application, when K n1After adjusting to the appropriate proportional coefficient, before the transistor M1 works in the subthreshold region, the voltage division signal V D The voltage division ratio ratio changes with the measured signal V BUS When the transistor M1 works in the subthreshold region, the voltage signal V D The voltage division ratio ratio changes with the measured signal V BUS The voltage value decreases first and then increases; when the transistor M1 works in the saturation region, the voltage division signal V D The voltage division ratio ratio changes with the measured signal V BUS The voltage value increases.

[0070] pass Figure 7 It can be clearly seen that as the measured signal V BUS The voltage value increases. Compared with the prior art, the voltage division signal V D The voltage divider ratio changes less and is closer to the ideal value 1 / N Rd .

[0071] Figure 8 FIG. 4 is a schematic diagram showing a simulation of a voltage division signal provided by the first embodiment of the present invention at different temperatures.

[0072] See also Figure 8 , which is N Rd =10 as an example, the voltage division signal V obtained at different temperatures (-40℃ / 25℃ / 125℃) D The voltage divider ratio error simulation diagram is shown in Figure 1. Figure 8 , when the measured signal V BUS In the range of 0-20V, the voltage division ratio produces a maximum error of only about 0.79‰ (temperature is -40℃), which effectively improves the voltage division signal V D The output accuracy of

[0073] However, since the threshold voltage Vth of transistor M1 changes with temperature, the higher the temperature, the lower the threshold voltage Vth, and the larger the current value of the voltage divider ratio compensation current I2. At different temperatures, the voltage divider ratio error error changes greatly with temperature. The voltage divider ratio error error has a lower flip point at high temperatures and a higher flip point at low temperatures, resulting in the voltage divider signal V at different temperatures. D In order to reduce the influence of temperature on the voltage divider ratio error, the inventors of this application have Figure 5 The compensation circuit shown has been improved accordingly.

[0074] Fig. 9 A circuit diagram of a resistor voltage divider circuit and a compensation circuit thereof according to a second embodiment of the present invention is shown.

[0075] See also Fig. 9 The compensation circuit provided in the second embodiment of the present invention further includes a temperature compensation module 220 .

[0076] The temperature compensation module 220 is connected to the voltage division ratio compensation module 210. More specifically, the temperature compensation module 220 is connected to the middle node of the transistor M1 and the resistor R1. The temperature compensation module 220 is used to generate a temperature compensation current I3 and input the temperature compensation current I3 to the voltage division ratio compensation module 210 to adjust the current value of the voltage division ratio compensation current I2, thereby achieving temperature compensation for the voltage division ratio.

[0077] The temperature compensation module 220 includes a resistor R2 and a transistor M2 which are sequentially connected between a power supply voltage VDD and an intermediate node between the transistor M1 and the resistor R1. The control terminal of the transistor M2 receives a reference voltage Vref, wherein the voltage value of the reference voltage Vref can be set as required.

[0078] The working principle of the temperature compensation module 220 is as follows: the threshold voltage Vth2 of the transistor M2 will also decrease with the increase of temperature. When the temperature is high, the temperature compensation current I3 flowing from the transistor M2 to the resistor R1 increases, so that the voltage Vx of the intermediate node between the transistor M1 and the resistor R1 increases, and the voltage-dividing ratio compensation current I2 decreases; when the temperature is low, the temperature compensation current I3 flowing from the transistor M2 to the resistor R1 decreases, so that the voltage Vx decreases and the voltage-dividing ratio compensation current I2 increases. Therefore, the temperature compensation current I3 is generated by the transistor M2 and the resistor R2, and the voltage-dividing signal V D Temperature compensation of the voltage divider ratio.

[0079] Furthermore, the transistors M1 and M2 are N-type metal-oxide-semiconductor (N-Metal-Oxide-Semiconductor) field effect transistors, referred to as NMOS transistors.

[0080] Fig.10 FIG. 4 is a schematic diagram showing a simulation of a voltage division signal provided by the second embodiment of the present invention at different temperatures.

[0081] See also Fig.10 , which is N Rd =10 as an example, the simulation diagram of the voltage division ratio error of the voltage division signal obtained at different temperatures (-40℃ / 25℃ / 125℃). Figure 8 and Fig.10 It can be seen that the voltage-divided signal V after compensation by the compensation circuit of the second embodiment of the present invention is D The voltage divider ratio error changes less with temperature.

[0082] According to the embodiments of the present invention, as described above, these embodiments do not describe all the details in detail, nor do they limit the invention to specific embodiments. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and the modified use based on the present invention. The scope of protection of the present invention shall be based on the scope defined by the claims of the present invention and their equivalents.

Claims

1. A compensation circuit for a resistor voltage divider circuit, wherein the resistor voltage divider circuit converts a signal to be measured into a voltage divider signal by resistor voltage divider, and outputs the voltage divider signal from a voltage divider node, the compensation circuit comprising: The voltage division ratio compensation module is connected to the voltage division node and is used to selectively perform voltage division ratio compensation on the voltage division signal according to the voltage value of the signal to be measured.

2. The compensation circuit according to claim 1, wherein: The voltage division ratio compensation module does not perform voltage division ratio compensation on the voltage division signal when the voltage value of the signal to be measured is less than a first threshold voltage, and performs voltage division ratio compensation on the voltage division signal according to the voltage value of the signal to be measured when the voltage value of the signal to be measured is greater than / equal to the first threshold voltage.

3. The compensation circuit according to claim 2, wherein: The voltage division ratio compensation module comprises: A control unit, which converts the signal to be measured into a control signal by means of resistance voltage division; The compensation unit is used to selectively extract a voltage division ratio compensation current from the voltage division node according to the control signal, so as to selectively perform voltage division ratio compensation on the voltage division signal.

4. The compensation circuit according to claim 3, wherein: The voltage value of the control signal is smaller than the voltage value of the voltage-divided signal.

5. The compensation circuit according to claim 3, wherein: When the voltage value of the signal to be measured is less than the first threshold voltage, the compensation unit does not extract the voltage-dividing ratio compensation current from the voltage-dividing node; when the voltage value of the signal to be measured is greater than / equal to the first threshold voltage, the compensation unit extracts the voltage-dividing ratio compensation current from the voltage-dividing node, and when the voltage value of the signal to be measured is greater than / equal to the first threshold voltage and less than the second threshold voltage, the voltage-dividing ratio compensation current is made to have an exponential relationship with the control signal, and when the voltage value of the signal to be measured is greater than / equal to the second threshold voltage, the voltage-dividing ratio compensation current is made to have a linear relationship with the control signal.

6. The compensation circuit according to claim 3, further comprising: The temperature compensation module is connected to the voltage division ratio compensation module and is used to generate a temperature compensation current and input the temperature compensation current to the voltage division ratio compensation module to adjust the current value of the voltage division ratio compensation current.

7. The compensation circuit according to claim 6, wherein: The control unit comprises: The first voltage-dividing resistor and the second voltage-dividing resistor are connected in sequence between the voltage to be measured and the ground terminal, and an intermediate node between the first voltage-dividing resistor and the second voltage-dividing resistor provides the control signal.

8. The compensation circuit according to claim 7, wherein: The compensation unit comprises: A first transistor and a first resistor are connected between the voltage division node and the ground terminal in sequence. The control terminal of the first transistor receives the control signal. The voltage division ratio compensation current flows through the first transistor and the first resistor.

9. The compensation circuit according to claim 8, wherein: The temperature compensation module comprises: A second resistor and a second transistor are connected in sequence between a power supply voltage and an intermediate node between the first transistor and the first resistor. A control terminal of the second transistor receives a reference voltage. The temperature compensation current flows through the second resistor and the second transistor.

10. The compensation circuit according to claim 9, wherein: The first transistor and the second transistor are NMOS transistors.

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