Temperature compensation circuit

Abstract

The embodiment of the invention discloses a temperature compensation circuit. The control ends of the first transistor, the second transistor, the third transistor and the fourth transistor in the current mirror are coupled. The currents of the output ends of the second transistor to the fourth transistor are all proportional to the current of the output end of the first transistor. A first resistor in the first branch is connected with the output end of the second transistor. And a second resistor in the second branch is connected with the output end of the third transistor. The temperature coefficients of the first resistor and the second resistor are different. The first input end of the amplifier is connected with the output end of the first transistor; the output end of the amplifier is connected with the control end of the first transistor. The two input ends of the comparator respectively obtain the first voltage output by the output end of the second transistor and the second voltage output by the output end of the third transistor and compare the first voltage and the second voltage. And the switching module is connected with the output end of the comparator, and outputs the first voltage and the second voltage to the second input end of the amplifier after proportionally weighting the first voltage and the second voltage.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to integrated circuit technology, and relate to but are not limited to a temperature compensation circuit. BACKGROUND

[0002] In radio frequency, analog integrated circuit system and module, circuit temperature characteristic is a very important parameter. With the change of temperature, linearly changing current or nonlinearly changing current can be generated in the circuit, and temperature sensor or temperature compensation current circuit needs to be used to carry out linear current compensation and nonlinear current compensation, so as to reduce the influence of temperature on the performance of the circuit. Among them, the compensation of nonlinearly changing current is more difficult, the structure of the compensation circuit is complex, and the temperature compensation effect is poor. SUMMARY

[0003] Therefore, embodiments of the present application provide a temperature compensation circuit to solve at least one problem in the prior art. The circuit has simple structure, low power consumption and small space occupation. By changing the weighting proportion of different temperature characteristic branches, dynamic compensation of current change is realized.

[0004] The technical scheme of the embodiments of the present application is implemented as follows: The embodiments of the present application provide a temperature compensation circuit. The temperature compensation circuit comprises a current mirror, a first branch and a second branch, an amplifier, a comparator and a switching module.

[0005] The current mirror comprises a first transistor, a second transistor, a third transistor and a fourth transistor; the control end of the first transistor, the control end of the second transistor, the control end of the third transistor and the control end of the fourth transistor are coupled together; the current at the output end of the second transistor, the current at the output end of the third transistor and the current at the output end of the fourth transistor are proportional to the current at the output end of the first transistor; the first branch comprises a first resistor, and the first resistor is connected to the output end of the second transistor; the second branch comprises a second resistor, and the second resistor is connected to the output end of the third transistor; wherein the temperature coefficient of the first resistor and the temperature coefficient of the second resistor are different; the amplifier comprises a first input end, a second input end and an output end; the first input end is connected to the output end of the first transistor; the output end of the amplifier is connected to the control end of the first transistor; the comparator has two input ends connected to the output end of the second transistor and the output end of the third transistor respectively, and is configured to obtain a first voltage output by the output end of the second transistor and a second voltage output by the output end of the third transistor respectively, and compare the first voltage and the second voltage; the switching module is connected to the output end of the comparator, and is configured to change the weighting proportion of the first voltage and the second voltage after the comparison, and output to the second input end.

[0006] In some embodiments, the switching module is configured to selectively connect the output terminal of the second transistor to the second input terminal of the amplifier, or connect the output terminal of the third transistor to the second input terminal of the amplifier.

[0007] In some embodiments, the switching module comprises a first switch and a second switch. The first terminal of the first switch is connected to the output terminal of the second transistor, the second terminal of the first switch is connected to the second input terminal, and the control terminal of the first switch is connected to one output terminal of the comparator; the first switch is configured to connect the second input terminal to the output terminal of the second transistor in response to the first control signal output by the comparator being in an on state, and the voltage of the second input terminal is equal to the first voltage.

[0008] The first terminal of the second switch is connected to the output terminal of the third transistor, the second terminal of the second switch is connected to the second input terminal, and the control terminal of the second switch is connected to the other output terminal of the comparator; the second switch is configured to connect the second input terminal to the output terminal of the third transistor in response to the second control signal output by the comparator being in an on state, and the voltage of the second input terminal is equal to the second voltage.

[0009] In some embodiments, the switching module comprises a plurality of voltage division unit groups and a switch unit, and each voltage division unit group comprises a first voltage division element and a second voltage division element. The input terminal of the first voltage division element is connected to the output terminal of the second transistor, the output terminal of the first voltage division element is connected to the second input terminal of the amplifier, the input terminal of the second voltage division element is connected to the output terminal of the third transistor, and the output terminal of the second voltage division element is connected to the second input terminal of the amplifier.

[0010] The ratio of the voltage division coefficients of the first voltage division element and the second voltage division element of each voltage division unit group is different.

[0011] The switch unit is configured to selectively turn on different voltage division unit groups to the second input terminal of the amplifier.

[0012] In some embodiments, the switching module comprises two voltage division unit groups; in one voltage division unit group, the first voltage division element comprises a third resistor and the second voltage division element comprises a fourth resistor; in the other voltage division unit group, the first voltage division element comprises a fifth resistor and the second voltage division element comprises a sixth resistor.

[0013] The switch unit comprises: a third switch and a fourth switch, the third resistor and the third switch are connected in series between the first branch and the second input terminal, the fourth resistor and the fourth switch are connected in series between the second branch and the second input terminal; control terminals of the third switch and the fourth switch are connected to one output terminal of the comparator, and are configured to connect the second input terminal to the output terminal of the second transistor and the output terminal of the third transistor in response to the first control signal output by the comparator being in an on state.

[0014] a fifth switch and a sixth switch, the fifth resistor and the fifth switch are connected in series between the first branch and the second input terminal, the sixth resistor and the sixth switch are connected in series between the second branch and the second input terminal; control terminals of the fifth switch and the sixth switch are connected to another output terminal of the comparator, and are configured to connect the second input terminal to the output terminal of the second transistor and the output terminal of the third transistor in response to the second control signal output by the comparator being in an on state.

[0015] a ratio of resistance values of the third resistor and the fourth resistor is different from a ratio of resistance values of the fifth resistor and the sixth resistor.

[0016] In some embodiments, a temperature coefficient of the third resistor, a temperature coefficient of the fourth resistor, a temperature coefficient of the fifth resistor, and a temperature coefficient of the sixth resistor are all zero temperature coefficients.

[0017] In some embodiments, an aspect ratio of the first transistor, an aspect ratio of the second transistor, and an aspect ratio of the third transistor are the same.

[0018] In some embodiments, the input terminal of the first transistor, the input terminal of the second transistor, the input terminal of the third transistor, and the input terminal of the fourth transistor are respectively connected to a first power supply voltage terminal.

[0019] The temperature compensation circuit further comprises a first unidirectional conduction unit, one end of the first unidirectional conduction unit is connected to the first input terminal, and the other end of the first unidirectional conduction unit is connected to a second power supply voltage terminal.

[0020] The first branch further comprises a second unidirectional conduction unit, a first end of the second unidirectional conduction unit is connected to the first resistor, and the other end of the second unidirectional conduction unit is connected to the second power supply voltage terminal.

[0021] The second branch further comprises a third unidirectional conduction unit, one end of the third unidirectional conduction unit is connected to the second resistor, and the other end of the third unidirectional conduction unit is connected to the second power supply voltage terminal.

[0022] In some embodiments, the second unidirectional conducting unit, the third unidirectional conducting unit, the first resistor and the second resistor satisfy the following relationship: The size of the second unidirectional conducting unit is greater than the size of the third unidirectional conducting unit, and the resistance of the first resistor is greater than the resistance of the second resistor at a fixed temperature point; The size of the second unidirectional conducting unit is equal to the size of the third unidirectional conducting unit, and the resistance of the first resistor is equal to the resistance of the second resistor at the fixed temperature point; The size of the second unidirectional conducting unit is less than the size of the third unidirectional conducting unit, and the resistance of the first resistor is less than the resistance of the second resistor at the fixed temperature point.

[0023] In some embodiments, the temperature coefficient of the first resistor is zero temperature coefficient, and the temperature coefficient of the second resistor is positive temperature coefficient or negative temperature coefficient; or, the temperature coefficient of the first resistor and the temperature coefficient of the second resistor are both positive temperature coefficient or negative temperature coefficient.

[0024] In some embodiments, the amplifier includes at least one of a five-tube amplifier, a sleeve amplifier and a folded amplifier.

[0025] In some embodiments, the comparator includes a static comparator or a dynamic comparator.

[0026] In the above temperature compensation circuit, the temperature coefficients of the first resistor and the second resistor are different, so that the first branch and the second branch form currents with different temperature coefficients; because the first voltage and the second voltage come from the first branch and the second branch, the first voltage and the second voltage retain the temperature characteristics of the first branch and the second branch, and the size relationship of the first voltage and the second voltage can reflect the size relationship of the currents flowing through the first branch and the second branch. The output of the comparator is triggered to flip by comparing the first voltage and the second voltage, and the comparison result of the comparator further triggers the switching module to change the weighting proportion of the first voltage and the second voltage accessing the negative feedback loop of the amplifier; the negative feedback formed by the amplifier + the first transistor + the second transistor + the third transistor can make the current flowing through the first transistor have different temperature coefficient slopes at different temperatures; and the fourth transistor copies the current of the first transistor, and the temperature compensation current output by the fourth transistor can have different slopes at different temperatures, so as to output a nonlinear temperature compensation current.

[0027] The present scheme does not require an external temperature sensor, and through the temperature characteristics of the first resistor and the second resistor and the dynamic switching mechanism of the switching module, the temperature coefficient slope switching of the temperature compensation current is realized, while the power consumption and area occupation of the circuit are reduced.

[0028] The switching module changes the weighted proportion of the first voltage and the second voltage, including two schemes: First, the weighting coefficients of the first voltage and the second voltage of the switching module are 100% and 0% respectively, or 0% and 100% respectively. That is, the switching module is configured to connect the second input end to the first branch or the second branch, so that the switching of the two temperature coefficient slopes can be conveniently realized.

[0029] Second, the voltage of the second input end is a weighted sum of part of the first voltage and part of the second voltage, and the switching module is configured to change the mixing proportion of the first voltage and the second voltage. By proportional mixing, any temperature coefficient slope combination can be realized, and flexibility is improved.

[0030] In some embodiments, the temperature compensation circuit further comprises a first unidirectional conduction unit, one end of the first unidirectional conduction unit being connected to the first input end, and the other end of the first unidirectional conduction unit being connected to the second power supply voltage end; the first branch further comprises a second unidirectional conduction unit, a first end of the second unidirectional conduction unit being connected to the first resistor, and the other end of the second unidirectional conduction unit being connected to the second power supply voltage end; the second branch further comprises a third unidirectional conduction unit, one end of the third unidirectional conduction unit being connected to the second resistor, and the other end of the third unidirectional conduction unit being connected to the second power supply voltage end. The second unidirectional conduction unit, the third unidirectional conduction unit, the first resistor and the second resistor satisfy the following relationships: the size of the second unidirectional conduction unit is greater than the size of the third unidirectional conduction unit; at a fixed temperature point, the resistance value of the first resistor is greater than the resistance value of the second resistor; the size of the second unidirectional conduction unit is equal to the size of the third unidirectional conduction unit, and at a fixed temperature point, the resistance value of the first resistor is equal to the resistance value of the second resistor; the size of the second unidirectional conduction unit is less than the size of the third unidirectional conduction unit; at a fixed temperature point, the resistance value of the first resistor is less than the resistance value of the second resistor. Based on the intersection of the two currents of the first resistor and the second resistor at a fixed temperature point, the current at the fixed temperature point is automatically switched through the comparator, and seamless connection of current switching can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0031] In the drawings, like reference numerals can describe similar components throughout the several views. Like reference numerals with different letter suffixes can represent different instances of the similar components. The drawings illustrate generally, by way of example, various embodiments discussed in the present document.

[0032] Figure 1 The structure schematic diagram of the temperature compensation circuit provided for some examples; Figure 2 For Figure 1 The actual output of the temperature compensation circuit shown is compared with the target output of the temperature compensation current; Figure 3A structure schematic diagram of a temperature compensation circuit provided by an embodiment of the present application is shown in the figure. Figure 4 A structure schematic diagram of two comparators provided by an embodiment of the present application is shown in (a) and (b) of the figure. Figure 5 A change relation between two temperature compensation currents of different temperature coefficients of a temperature compensation circuit provided by an embodiment of the present application and temperature is shown in the figure. Figure 6 A structure schematic diagram of another temperature compensation circuit provided by an embodiment of the present application is shown in the figure. Figure 7A A structure schematic diagram of a temperature compensation circuit provided by an embodiment of the present application is shown in the figure. Figure 6 Figure 7B A structure schematic diagram of a temperature compensation circuit provided by an embodiment of the present application is shown in the figure. Figure 6 A structure schematic diagram of another temperature compensation circuit provided by an embodiment of the present application is shown in the figure. Figure 8 A change relation between a nonlinear temperature compensation current output by a temperature compensation circuit provided by an embodiment of the present application and temperature is shown in the figure. Figure 9 Figure 6 A structure schematic diagram of another temperature compensation circuit provided by an embodiment of the present application is shown in the figure. Figure 10 A structure schematic diagram of a temperature compensation circuit provided by an embodiment of the present application is shown in the figure. Figure 11A A structure schematic diagram of a temperature compensation circuit provided by an embodiment of the present application is shown in the figure. Figure 10 A structure schematic diagram of a temperature compensation circuit provided by an embodiment of the present application is shown in the figure. Figure 11B Figure 10 A structure schematic diagram of a temperature compensation circuit provided by an embodiment of the present application is shown in the figure. Figure 12 A change relation between a nonlinear temperature compensation current output by a temperature compensation circuit provided by an embodiment of the present application and temperature is shown in the figure. Figure 10 DETAILED DESCRIPTION

[0033] The technical solutions of the present application are further described in detail below in combination with the accompanying drawings and specific embodiments.

[0034] The terms "first", "second", and similar terms used in the present application do not represent any order, quantity, or importance, but are only used to distinguish different components. Similarly, the terms "one", "an", or "the" do not represent a quantity limitation, but represent the existence of at least one. The terms "connected" or "connected" or "coupled" and similar terms are not limited to physical or mechanical coupling, but can include electrical coupling, whether direct or indirect. ​​​​

[0035] It should be understood that every feature, structure, or characteristic described in relation to an embodiment is within the scope of at least one embodiment of the present application. Therefore, whenever a particular feature, structure, or characteristic is described in the context of an embodiment, it is intended to mean that a particular feature, structure, or characteristic is included in at least one embodiment. Additionally, it should be understood that the features, structures, or characteristics of one embodiment can be combined with those of another embodiment in any suitable manner. It should be understood that the sequence of the processes described above in various embodiments of the present application does not mean the order of execution, and the execution order of the processes should be determined according to their functions and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application. The sequence of the embodiments of the present application described above is only for description, and does not represent the advantages or disadvantages of the embodiments.

[0036] It should be noted that the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without more limitations, an element defined by the statement "comprising a" does not exclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0037] It should be noted that although the present specification is described in terms of embodiments, not every embodiment includes only one independent technical solution, and the description of the specification is only for clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand.

[0038] In radio frequency, analog integrated circuit systems and modules, circuit temperature characteristics are very important parameters. For example, inconsistent receiver link gain temperature drift will change the sensitivity and dynamic range at different temperatures; inconsistent transmitter link gain temperature drift may cause the gain vector magnitude (EVM) to deteriorate at different temperatures; inconsistent gain temperature drift in the detector link will cause the detection error to increase at different temperatures; inconsistent oscillator frequency temperature drift will cause the phase-locked loop to lose lock and other phenomena.

[0039] Therefore, it is generally necessary to ensure that the circuit characteristics remain consistent with temperature changes (of course, there may be some special scenarios that require to maintain specific temperature change characteristics). However, due to the active devices that make up the circuit, the device parameters will generally change with temperature, and to suppress the change in circuit temperature characteristics caused by device parameter changes, temperature compensation circuits are usually used to correct.

[0040] Temperature compensation circuits are generally divided into linear temperature compensation and nonlinear temperature compensation. Since the linear temperature compensation technology is low in difficulty and easy to implement, it is generally adopted in scenarios where the requirement for temperature compensation current (temperature compensation current) is not high. However, for scenarios with higher requirements for temperature compensation current (for example, the change may be nonlinear with temperature), nonlinear temperature compensation technology is very important. Compared with linear temperature compensation, nonlinear temperature compensation can keep the gain consistent in a larger temperature range. However, the technology is high in difficulty and the circuit structure is relatively complex.

[0041] As shown in FIG. 1, Figure 1 A nonlinear temperature compensation circuit includes two temperature compensation current output circuits with different temperature characteristics (the slopes of the linear temperature compensation currents IPTAT1 and IPTAT2 output by the two circuits change with temperature), a multiplexer, and a temperature sensor. One temperature compensation current output circuit includes transistors M1-M3, an amplifier, transistors Q1 and Q2, and a resistor RT1. The other temperature compensation current output circuit includes transistors M4-M6, an amplifier, transistors Q3 and Q4, and a resistor RT2. The temperature of the circuit is sensed by the temperature sensor. When the temperature is lower than a temperature value T, the temperature sensor generates a control signal to control the multiplexer to select IPTAT1 as the output. When the temperature reaches and exceeds the temperature value T, the temperature sensor generates a control signal to control the multiplexer to select IPTAT2 as the output, thereby achieving switching of the temperature compensation current IPTAT. As shown in FIG. 1, Figure 2 (a), because the slopes of the two linear temperature compensation currents change with temperature, when the two linear temperature compensation currents IPTAT1 and IPTAT2 are spliced together, a nonlinear temperature compensation current is finally generated.

[0042] The inventor has found that by setting the temperature compensation current output circuit to be externally connected to the multiplexer and the temperature sensor, the circuit structure of the multiplexer and the temperature sensor occupies a large space, which is not conducive to reducing the size of the integrated circuit structure of the entire output nonlinear temperature compensation current, and the power consumption is large. Moreover, the temperature sensor has limited accuracy in sensing temperature changes, and it is difficult to accurately switch at the theoretical intersection temperature T, which is prone to temperature compensation current connection problems. For example, when the two linear temperature compensation currents IPTAT1 and IPTAT2 are spliced together at the temperature value T, the target temperature compensation current (as shown in FIG. 1, Figure 2 (d)) is quite different from the actual obtained temperature compensation current (as shown in FIG. 1, Figure 2 (b) or (c)), which seriously affects the accuracy and reliability of temperature compensation.

[0043] For example, as shown in FIG. 2, Figure 2As shown in (b), the temperature value sensed by the temperature sensor is greater than the actual temperature value T of the intersection of the linear temperature compensation current IPTAT1 and IPTAT2, and the multiplexer will delay switching IPTAT1 to IPTAT2. Figure 2 In the relationship between the linear temperature compensation currents IPTAT1 and IPTAT2 and the temperature value T shown in (a), when the temperature is greater than T, the output nonlinear temperature compensation current IPTAT suddenly increases from the current value IPTAT1 to the current value IPTAT2.

[0044] For example, Figure 2 As shown in (c), the temperature value sensed by the temperature sensor is lower than the actual temperature value T of the intersection of the linear temperature compensation current IPTAT1 and IPTAT2, and the multiplexer will switch IPTAT1 to IPTAT2 in advance. Figure 2 In the relationship between the linear temperature compensation currents IPTAT1 and IPTAT2 and the temperature value T shown in (a), when the temperature is lower than T, the output nonlinear temperature compensation current IPTAT drops sharply from the current value IPTAT1 to the current value IPTAT2.

[0045] In order to solve the above problems, an embodiment of the present application provides a temperature compensation circuit that does not require a temperature sensor. The circuit automatically and accurately selects or mixes compensation paths of different branches based on the comparison results of internal branch voltages through an integrated comparator and switching module. The entire circuit structure is simple, occupies a small space, and has low power consumption.

[0046] like Figure 3 As shown, the temperature compensation circuit 100 includes: a current mirror 110 , a first branch 120 , a second branch 130 , an amplifier 140 , a comparator 150 and a switching module 160 .

[0047] The current mirror 110 includes a first transistor T1, a second transistor T2, a third transistor T3, and a fourth transistor T4. The control terminals of the first through fourth transistors T1 through T4 are coupled together; the input terminals (sources) of the first through fourth transistors T1 through T4 are respectively connected to a first power supply voltage terminal (e.g., VDD). This ensures that the currents at the output terminals (drains) of the second through fourth transistors T2 through T4 replicate the current at the output terminal of the first transistor T1 at a certain ratio.

[0048] The first branch 120 is connected to the output terminal of the second transistor T2, and includes a first resistor R1. Specifically, the output terminal of the second transistor T2 is coupled to one end of the first resistor R1 through a first node N1. The first node N1 has a first voltage V1, and the current flowing through the second transistor T2 and the resistance value of the first resistor R1 affect the first voltage V1 of the first node N1. Therefore, the magnitude of the first voltage V1 can represent the temperature characteristic of the first resistor R1.

[0049] The second branch 130 is connected to the output terminal of the third transistor T3, and includes a second resistor R2. Specifically, the output terminal of the second transistor T2 is coupled to one end of the second resistor R2 through a second node N2. The second node N2 has a second voltage V2. The current flowing through the third transistor T3 and the resistance value of the second resistor R2 affect the second voltage V2 of the second node N2. Therefore, the magnitude of the second voltage V2 can represent the temperature characteristic of the second resistor R2.

[0050] The temperature coefficient of the first resistor R1 and the temperature coefficient of the second resistor R2 are different. It should be noted that the temperature coefficient is a parameter used to describe the rate of change of current value or resistance value with temperature, and is expressed as the relative change rate of current value or resistance value caused by unit temperature change. The temperature coefficient of resistance is expressed as the relative change rate of resistance value caused by unit temperature change. The temperature coefficient of current is expressed as the relative change rate of current value caused by unit temperature change. According to the different temperature coefficients of the first resistor R1 and the second resistor R2, the current flowing through the first branch 120 and the second branch 130 has different slopes with temperature change, which provides a basis for subsequent nonlinear compensation through the comparator 150 and the switching module 160.

[0051] Thus, continuing to refer to Figure 3 The amplifier 140 includes a first input terminal, a second input terminal, and an output terminal. For example, the first input terminal of the amplifier 140 is the inverting input terminal (-), and the second input terminal is the non-inverting input terminal (+). The first input terminal of the amplifier 140 is connected to the output terminal of the first transistor T1; the second input terminal of the amplifier 140 is connected to the switching module 160; and the output terminal of the amplifier 140 is connected to the control terminal of the first transistor T1, thereby forming a negative feedback loop with the first transistor T1 and the second transistor T2 / third transistor T3 to clamp the voltage between the first input terminal and the second input terminal.

[0052] Continuing to refer to Figure 3The two input terminals of the comparator 150 are respectively connected to the output terminals of the second transistor T2 and the third transistor T3, one input terminal of the comparator 150 is coupled to the first node N1 to obtain the first voltage V1, and the other input terminal is coupled to the second node N2 to obtain the second voltage V2. The comparator 150 compares the sizes of the first voltage V1 and the second voltage V2, and outputs a corresponding control signal according to the comparison result, which is configured to drive the subsequent switching module 160 to realize the switching or mixing of the branches. Specifically, when V1 < V2, the comparator 150 outputs a first comparison result; when V1 ≥ V2, the comparator 150 outputs a second comparison result. For example, as shown in Figure 3 , the switching module 160 needs two control signals for switching or mixing, so the comparison result output by the comparator 150 includes a first control signal Ctrl1 and a second control signal Ctrl2, wherein the first control signal Ctrl1 and the second control signal Ctrl2 can be mutually inverse signals, when the first control signal Ctrl1 is 1, the second control signal Ctrl2 is 0; when the first control signal Ctrl1 is 0, the second control signal Ctrl2 is 1.

[0053] Continuing to refer to Figure 3 , the switching module 160 includes a first input terminal connected to the first branch 120, a second input terminal connected to the second branch 130, a control terminal connected to the output terminal of the comparator 150, and an output terminal connected to the second input terminal (+) of the amplifier 140. For example, the first input terminal of the switching module 160 is configured to receive the first voltage V1 transmitted by the output terminal of the second transistor T2 in the first branch 120. The second input terminal of the switching module 160 is configured to receive the second voltage V2 transmitted by the output terminal of the third transistor T3 in the second branch 130. The two control terminals of the switching module 160 are respectively connected to the two input terminals configured to receive different control signals. The output terminal of the switching module 160 is configured to output the weighted sum of the first voltage V1 and the second voltage V2.

[0054] For example, the control end of the switching module 160 is connected to the comparator 150, which is configured to change the weighting proportion of the first voltage V1 and the second voltage V2 based on the comparison result of the comparator 150 (for example, the first control signal Ctrl1 and the second control signal Ctrl2). For example, when the comparator 150 outputs the first comparison result, the voltage (B-point voltage) VB at the output end of the switching module 160 is: a1 x the first voltage V1 + a2 x the second voltage V2 (Formula 1); when the comparator 150 outputs the second comparison result, the voltage (B-point voltage) VB at the output end of the switching module 160 is: b1 x the first voltage V1 + b2 x the second voltage V2 (Formula 2), where a1: a2 ≠ b1: b2, and a1, a2, b1, and b2 are the weighting proportions. Then, the weighted voltage of the first voltage V1 and the second voltage V2 is output to the second input end of the amplifier 140.

[0055] In this way, in the temperature compensation circuit 100, the different temperature coefficients of the first resistor R1 and the second resistor R2 are used to make the first branch 120 and the second branch 130 form currents with different temperature coefficient slopes (see Figure 5 Because the first voltage V1 and the second voltage V2 come from the first branch 120 and the second branch 130, the first voltage V1 and the second voltage V2 retain the temperature characteristics of the respective branches, and the size relationship between the first voltage V1 and the second voltage V2 can reflect the size relationship between the currents flowing through the first branch 120 and the second branch 130. The comparator 150 compares the first voltage V1 and the second voltage V2, and the comparison result drives the switching module 160 to dynamically change the proportion of the first voltage V1 and the second voltage V2 connected to the negative feedback loop of the amplifier 140; by using the negative feedback of the amplifier 140, the current flowing through the first transistor T1 will follow the temperature characteristic change of the connected branch; the fourth transistor T4 copies the current of the first transistor T1, and the current output by the fourth transistor T4 can reflect different temperature characteristics at different temperature points, thereby outputting a nonlinear temperature compensation current I C . Moreover, the present scheme does not require an external temperature sensor, and by using the double-resistor temperature characteristic coupling and the dynamic switching mechanism, the switching between different temperature coefficient slopes is realized, while the circuit power consumption and area occupation are reduced.

[0056] In some examples, the first transistor T1, the second transistor T2, the third transistor T3, and the fourth transistor T4 in the current mirror 110 can all be metal-oxide-semiconductor field-effect transistors (MOSFETs), bipolar transistors (BJTs), or transistors of other structures.

[0057] In the examples provided by the present application, the current mirror 110 adopts a single-tube MOS current mirror as an example for illustration, and under the same design idea, the current mirror 110 can also adopt other types of current mirrors. For example, a cascode current mirror, a Wilson current mirror, and the like. The examples provided by the present application do not limit the type of current mirror, and the type of current mirror can be selected according to actual needs.

[0058] As shown in FIG. 1, the output end of the first transistor T1, the output end of the second transistor T2, and the output end of the third transistor T3 output currents equal to each other. For example, the size of the second transistor T2 and the size of the third transistor T3 can be set to be consistent (the aspect ratio of the transistors is consistent), and the threshold voltage of the second transistor T2 and the threshold voltage of the third transistor T3 are equal, so that the replication ratio of the second transistor T2 to the first transistor T1 is equal to the replication ratio of the third transistor T3 to the first transistor T1. Figure 3 As shown in FIG. 1, the output end of the first transistor T1, the output end of the second transistor T2, and the output end of the third transistor T3 output currents equal to each other. For example, the size of the second transistor T2 and the size of the third transistor T3 can be set to be consistent (the aspect ratio of the transistors is consistent), and the threshold voltage of the second transistor T2 and the threshold voltage of the third transistor T3 are equal, so that the replication ratio of the second transistor T2 to the first transistor T1 is equal to the replication ratio of the third transistor T3 to the first transistor T1.

[0059] Figure 4 As shown in FIG. 1, the output end of the first transistor T1, the output end of the second transistor T2, and the output end of the third transistor T3 output currents equal to each other. For example, the size of the second transistor T2 and the size of the third transistor T3 can be set to be consistent (the aspect ratio of the transistors is consistent), and the threshold voltage of the second transistor T2 and the threshold voltage of the third transistor T3 are equal, so that the replication ratio of the second transistor T2 to the first transistor T1 is equal to the replication ratio of the third transistor T3 to the first transistor T1. Figure 4 As shown in FIG. 1, the output end of the first transistor T1, the output end of the second transistor T2, and the output end of the third transistor T3 output currents equal to each other. For example, the size of the second transistor T2 and the size of the third transistor T3 can be set to be consistent (the aspect ratio of the transistors is consistent), and the threshold voltage of the second transistor T2 and the threshold voltage of the third transistor T3 are equal, so that the replication ratio of the second transistor T2 to the first transistor T1 is equal to the replication ratio of the third transistor T3 to the first transistor T1.

[0060] As shown in FIG. 1, the output end of the first transistor T1, the output end of the second transistor T2, and the output end of the third transistor T3 output currents equal to each other. For example, the size of the second transistor T2 and the size of the third transistor T3 can be set to be consistent (the aspect ratio of the transistors is consistent), and the threshold voltage of the second transistor T2 and the threshold voltage of the third transistor T3 are equal, so that the replication ratio of the second transistor T2 to the first transistor T1 is equal to the replication ratio of the third transistor T3 to the first transistor T1.

[0061] In some examples, as shown in FIG. 1, the amplifier 140 can include at least one of a five-tube amplifier, a sleeve amplifier, and a folded amplifier. The examples provided by the present application do not limit this, and the type of amplifier can be selected according to actual needs. Figure 3 ​As shown, the temperature compensation circuit 100 further comprises a first unidirectional conducting unit U1, one end of the first unidirectional conducting unit U1 is connected with the first input end of the amplifier 140, and the other end of the first unidirectional conducting unit U1 is grounded. The first branch 120 comprises a second unidirectional conducting unit U2, the first end of the second unidirectional conducting unit U2 is connected with the first resistor R1, and the other end of the second unidirectional conducting unit U2 is grounded. The second branch 130 comprises a third unidirectional conducting unit U3, the first end of the third unidirectional conducting unit U3 is connected with the second resistor R2, and the other end of the third unidirectional conducting unit U3 is grounded. The unidirectional conducting unit can be a diode or a transistor connected in the form of a diode, which can generate a unidirectional current after applying a voltage, and a voltage difference with a positive temperature coefficient can be generated between two groups of unidirectional conducting units with different sizes, and used to generate a positive temperature coefficient current. For example, the first unidirectional conducting unit U1 and the second unidirectional conducting unit U2 are different in size, so that the first branch forms a positive temperature coefficient current; the first unidirectional conducting unit U1 and the third unidirectional conducting unit U3 are different in size, so that the second branch forms a positive temperature coefficient current. When the unidirectional conducting unit can be a diode, the size is the area of the PN junction; when the unidirectional conducting unit can be a transistor connected in the form of a diode, the size is the length-width ratio of the channel.

[0062] The sizes of the second unidirectional conducting unit U2 and the third unidirectional conducting unit U3 will affect the temperature coefficients of the currents in the first branch and the second branch, in order to achieve the purpose of smooth transition and seamless connection of the transmission currents of the two branches before and after switching at a fixed temperature point T. Then, the second unidirectional conducting unit U2, the third unidirectional conducting unit U3, the first resistor R1 and the second resistor R2 satisfy the following relationship: 1) If the size of the second unidirectional conducting unit U2 is equal to the size of the third unidirectional conducting unit U3, the resistance value of the first resistor R1 and the resistance value of the second resistor R2 are equal at the fixed temperature point Ta. Because the size of the second unidirectional conducting unit U2 is equal to the size of the third unidirectional conducting unit U3, the influence of the second unidirectional conducting unit U2 on the temperature coefficient of the first branch is consistent with the influence of the third unidirectional conducting unit U3 on the temperature coefficient of the second branch, and if the first resistor R1 and the second resistor R2 are not set, the temperature coefficients of the first branch current and the second branch current are the same. Because the temperature coefficients of the first resistor R1 and the second resistor R2 are different, the change rates of the first change curve of the resistance value of the first resistor R1 with temperature and the second change curve of the resistance value of the second resistor R2 with temperature are different. At the temperature corresponding to the intersection point of the first change curve and the second change curve (i.e. the fixed temperature point Ta), the resistance value of the first resistor R1 is equal to the resistance value of the second resistor R2, which is represented as Figure 5The temperature compensation currents of the first branch 120 and the second branch 130 are equal at the fixed temperature point Ta, the input voltages (V1 and V2) of the comparator 150 are equal, the comparison result of the comparator is reversed, and the switching module 160 is triggered to switch. Since the transmitted voltage and current of the two branches before and after switching are continuous at the fixed temperature point Ta, the smooth and seamless connection of the nonlinear temperature compensation current can be achieved. 2) If the size of the second unidirectional conduction unit U2 is greater than the size of the third unidirectional conduction unit U3, the resistance value of the first resistor R1 is greater than the resistance value of the second resistor R2 at the fixed temperature point. If the first resistor R1 and the second resistor R2 are not set, the temperature coefficient of the first branch current is greater than the temperature coefficient of the second branch current. At the fixed temperature point, the resistance value of the first resistor R1 is greater than the resistance value of the second resistor R2, and the first resistor R1 can lower the current of the first branch, so that the temperature compensation currents of the first branch 120 and the second branch 130 are equal at the fixed temperature point Ta, to achieve the purpose of smooth transition and seamless connection of the transmitted current of the two branches before and after switching at the fixed temperature point T. 3) If the size of the second unidirectional conduction unit U2 is less than the size of the third unidirectional conduction unit U3, the resistance value of the first resistor R1 is less than the resistance value of the second resistor R2 at the fixed temperature point. If the first resistor R1 and the second resistor R2 are not set, the temperature coefficient of the first branch current is less than the temperature coefficient of the second branch current. At the fixed temperature point, the resistance value of the first resistor R1 is less than the resistance value of the second resistor R2, and the second resistor R2 can lower the current of the second branch, so that the temperature compensation currents of the first branch 120 and the second branch 130 are equal at the fixed temperature point Ta, to achieve the purpose of smooth transition and seamless connection of the transmitted current of the two branches before and after switching at the fixed temperature point T.

[0063] In some examples, the first resistor R1 and the second resistor R2 can be set as thermistors, and the temperature coefficient and resistance value of the first resistor R1 and the second resistor R2 can be adjusted by setting the size (such as the aspect ratio) and material (such as polysilicon resistance) of the first resistor R1 and the second resistor R2, respectively. The size and material parameters can be adjusted according to actual conditions, and the examples provided in the present application do not make specific limitations.

[0064] It should be noted that the "fixed temperature point" corresponds to the turning point at which the slope of the to-be-temperature-compensated current changes significantly with temperature, i.e., the junction temperature of two different temperature response intervals. This "fixed temperature point" can be set according to the characteristics of the to-be-temperature-compensated current.

[0065] For example, the first resistor R1 and the second resistor R2 are both positive temperature coefficient resistors, and the positive temperature coefficient of the first resistor R1 is smaller than the positive temperature coefficient of the second resistor R2, that is, the change rate of the first change curve of the resistance value of the first resistor R1 with respect to temperature is smaller than the change rate of the second change curve of the resistance value of the second resistor R2 with respect to temperature. In this way, the change rates of the first change curve of the resistance value of the first resistor R1 with respect to temperature and the second change curve of the resistance value of the second resistor R2 with respect to temperature are different.

[0066] For another example, the first resistor R1 and the second resistor R2 are both negative temperature coefficient resistors, and the negative temperature coefficient of the first resistor R1 is greater than the negative temperature coefficient of the second resistor R2, that is, the change rate of the change curve of the resistance value of the first resistor R1 with respect to temperature is greater than the change rate of the change curve of the resistance value of the second resistor R2 with respect to temperature.

[0067] For another example, the first resistor R1 is a zero temperature coefficient resistor, and the second resistor R2 is a positive temperature coefficient or negative temperature coefficient resistor, so that the resistance value of the second resistor R2 with respect to temperature at a certain fixed temperature point Ta can be more conveniently set to be equal to the resistance value of the first resistor R1. The size of the first unidirectional conduction unit U1 and the size of the second unidirectional conduction unit U2 can be set to be different, for example, the first unidirectional conduction unit U1 and the second unidirectional conduction unit U2 are both transistors, the sizes (length-width ratios of channels) of the two transistors are different, and the difference between the voltage difference across the first unidirectional conduction unit U1 and the voltage difference across the second unidirectional conduction unit U2 is a positive temperature coefficient voltage difference. Even if the first resistor R1 is a zero temperature coefficient resistor, the current of the first branch 120 can also exhibit a positive temperature coefficient.

[0068] The above examples set the temperature characteristics of the voltage and current transmitted by the first branch 120 to be different from the temperature characteristics of the voltage and current transmitted by the second branch 130, and the voltage and current transmitted by the two branches are the same at a fixed temperature point. When the temperature changes to the fixed temperature point Ta, the input voltages (V1 and V2) across the comparator 150 are exactly equal, the comparison result of the comparator is reversed, and the switching module 160 is triggered to switch. Since the voltages and currents transmitted by the two branches before and after switching are continuous at the fixed temperature point Ta, the smooth and seamless connection of the nonlinear temperature compensation current can be achieved.

[0069] In some embodiments, as Figure 6As shown, the switching module 160 is configured to selectively: connect the output end (i.e., the first node N1) of the second transistor with the second input end of the amplifier 140, the switching module 160 having a weighting coefficient of 100% and 0% for the first voltage V1 and the second voltage V2 respectively, that is, in formula 1, a1 is 1 and a2 is 0; or, the switching module 160 connects the output end (i.e., the second node N2) of the third transistor T3 with the second input end of the amplifier 140, the switching module 160 having a weighting coefficient of 0% and 100% for the first voltage V1 and the second voltage V2 respectively, that is, in formula 2, b1 is 0 and b2 is 1.

[0070] As shown, Figure 6 The switching module 160 can include a first switch S1 and a second switch S2.

[0071] The first end of the first switch S1 is connected to the output end of the second transistor T2, the second end of the first switch S1 is connected to the second input end (+) of the amplifier 140, and the control end of the first switch S1 is connected to one output end of the comparator 150. The control end of the first switch S1 receives the first control signal Ctrl1 output by the comparator 150, and the first switch S1 is configured to be in a conductive state in response to the first control signal Ctrl1 output by the comparator 150. When the first switch S1 is conductive, the second input end of the amplifier 140 is connected to the output end of the second transistor T2, and the voltage of the second input end of the amplifier 140 is equal to the first voltage V1.

[0072] The first end of the first switch S1 is connected to the output end of the second transistor T2, the second end of the first switch S1 is connected to the second input end (+) of the amplifier 140, and the control end of the first switch S1 is connected to one output end of the comparator 150. The control end of the first switch S1 receives the first control signal Ctrl1 output by the comparator 150, and the first switch S1 is configured to be in a conductive state in response to the first control signal Ctrl1 output by the comparator 150. When the first switch S1 is conductive, the second input end of the amplifier 140 is connected to the output end of the second transistor T2, and the voltage of the second input end of the amplifier 140 is equal to the first voltage V1.

[0073] Taking the case where the size of the second unidirectional conduction unit U2 is equal to the size of the third unidirectional conduction unit U3, the resistance value of the first resistor R1 and the resistance value of the second resistor R2 are equal at a fixed temperature point Ta, as the temperature changes, in the temperature range less than the fixed temperature point Ta, the resistance value of the first resistor R1 is greater than the resistance value of the second resistor R2, the current of the first branch 120 is less than the current of the second branch 130, and the first voltage V1 is less than the second voltage V2. As shown, Figure 7AAs shown, the comparator 150 outputs the first control signal Ctrl1 and the second control signal Ctrl2, the first switch S1 of the switching module 160 is turned on in response to the first control signal Ctrl1, and the output end (i.e. the first node N1) of the second transistor can be communicated with the second input end (+) of the amplifier 140; and the second switch S2 of the switching module 160 is turned off in response to the second control signal Ctrl2, and the second branch 130 is not communicated with the amplifier 140. Then the weighted value of the first voltage V1 transmitted by the first node N1 of the first branch 120 can be 100%, the weighted value of the second voltage V2 transmitted by the second node N2 of the second branch 130 can be 0%, and the first voltage V1 is output to the second input end of the amplifier 140. Wherein the temperature variation law of the node B coupled with the switching module 160 is consistent with the temperature characteristic of the first resistor R1 in the first branch 120. And the first input end of the amplifier 140 is coupled with the node A, and the second input end of the amplifier 140 is coupled with the node B, and the amplifier 140 can clamp the voltages of the node A and the node B, so that the voltages of the node A and the node B are consistent, and the temperature characteristics are consistent. By connecting the first voltage V1 of the first branch 120 to the feedback loop of the amplifier 140, the temperature compensation current Ic output from the fourth transistor T4 is related to the temperature characteristic of the first resistor R1.

[0074] When the temperature reaches the fixed temperature point Ta, the resistance value of the first resistor R1 is equal to the resistance value of the second resistor R2, the current of the first branch 120 is equal to the current of the second branch 130, and the first voltage V1 is equal to the second voltage V2. As shown in FIG. 2, when the temperature reaches the fixed temperature point Ta, the first voltage V1 and the second voltage V2 are equal, and the first branch 120 and the second branch 130 are in a balanced state. Figure 7BAs shown, the comparator 150 outputs the first control signal Ctrl1 and the second control signal Ctrl2, the second switch S2 of the switching module 160 is turned on in response to the second control signal Ctrl2, and the output end (i.e., the second node N2) of the third transistor can be connected to the second input end (+) of the amplifier 140; and the first switch S1 of the switching module 160 is turned off in response to the first control signal Ctrl1, and the first branch 120 is not connected to the amplifier 140. Then the weighted value of the first voltage V1 transmitted by the first node N1 of the first branch 120 can be 0%, the weighted value of the second voltage V2 transmitted by the second node N2 of the second branch 130 can be 100%, and the second voltage V2 is output to the second input end of the amplifier 140. Wherein, the temperature variation law of the node B coupled with the switching module 160 is consistent with the temperature characteristics of the second resistor R2 in the second branch 130. And, based on the first input end of the amplifier 140 being coupled with the node A and the second input end of the amplifier 140 being coupled with the node B, the amplifier 140 can clamp the voltages of the node A and the node B to make the voltages of the node A and the node B consistent, and the temperature characteristics are consistent. By connecting the second voltage V2 of the second branch 130 to the feedback loop of the amplifier 140, the temperature compensation current Ic output from the fourth transistor T4 is related to the temperature characteristics of the second resistor R2.

[0075] And, in the temperature range greater than the fixed temperature point, the resistance value of the first resistor R1 is less than the resistance value of the second resistor R2, the current of the first branch 120 is greater than the current of the second branch 130, and the first voltage V1 is greater than the second voltage V2. As shown Figure 7B As shown, the comparator 150 outputs the first control signal Ctrl1 and the second control signal Ctrl2, the switching module 160 continues to keep the first branch 120 connected to the amplifier 140, and the first branch 120 is not connected to the amplifier 140. And connect the output end (i.e., the first node N1) of the second transistor to the second input end of the amplifier 140, and output the second voltage V2 to the second input end of the amplifier 140.

[0076] In this way, different branches can be connected to the amplifier 140 through the switching module 160 according to different temperature variation ranges, and the current compensation of different degrees can be performed on the nonlinearly changed current by setting the temperature coefficient of the first resistor R1 and the temperature coefficient of the second resistor R2, thereby improving the temperature compensation current precision.

[0077] In other embodiments, when the size of the second unidirectional conductive unit U2 is larger than the size of the third unidirectional conductive unit U3, and the resistance of the first resistor R1 is greater than the resistance of the second resistor R2 at the fixed temperature point Ta, or when the size of the second unidirectional conductive unit U2 is smaller than the size of the third unidirectional conductive unit U3, and the resistance of the first resistor R1 is smaller than the resistance of the second resistor R2 at the fixed temperature point Ta, when the temperature reaches the fixed temperature point Ta, the voltage between the first voltage V1 and the second voltage V2 can also trigger the first control signal Ctrl1 and the second control signal Ctrl2 output by the comparator 150 to change, so as to control the switching module 160 to connect the output end of the second transistor (i.e., the first node N1) and the second input end of the amplifier 140, or control the switching module 160 to connect the output end of the third transistor T3 (i.e., the second node N2) and the second input end of the amplifier 140.

[0078] In the above example, the switching module 160 uses a plurality of independent switches to select the first voltage V1 or the second voltage V2 for transmission to the second input terminal of the amplifier 140 in response to different control signals. The switching module 160 may also use a single-pole double-throw switch, a multiplexer, or other electronic component or circuit configured to selectively connect at least one of the multiple branches to the second input terminal of the amplifier 140. This application does not impose any specific limitations on this, and the switching module 160 may be configured according to actual needs.

[0079] like Figure 6 As shown, the first unidirectional conducting unit U1 includes a fifth transistor T5. The fifth transistor T5 can be a PNP transistor. The first terminal of the fifth transistor T5 is connected to the first input terminal of the amplifier 140, and the second terminal of the fifth transistor T5 is connected to ground. The control terminal of the fifth transistor T5 is connected to the first terminal of the fifth transistor T5. The second unidirectional conducting unit U2 includes a sixth transistor T6, which can be a PNP transistor. The first terminal of the sixth transistor T6 is connected to the first resistor R1, the second terminal of the sixth transistor T6 is connected to ground, and the control terminal of the sixth transistor T6 is connected to the first terminal of the sixth transistor T6. The third unidirectional conducting unit U3 includes a seventh transistor T7, which can be a PNP transistor. The first terminal of the seventh transistor T7 is connected to the second resistor R2, the second terminal of the seventh transistor T7 is connected to ground, and the control terminal of the seventh transistor T7 is connected to the first terminal of the seventh transistor T7.

[0080] It should be noted that the "first terminal" of a transistor can be the emitter, the "second terminal" can be the collector, and the "control terminal" can be the base; alternatively, the "first terminal" can be the collector, the "second terminal" can be the emitter, and the "control terminal" can be the base. The examples provided in this application do not impose specific restrictions on the "first terminal" and "second terminal" and can be adjusted according to different transistor types.

[0081] In yet another embodiment, the fifth to seventh transistors can also be NPN type transistors. As shown, a first end of the fifth transistor T5 is connected to a first input end of the amplifier 140, and a second end of the fifth transistor T5 is connected to ground. A control end of the fifth transistor T5 is connected to the second end of the fifth transistor T5. That is, the fifth transistor T5 transmits current is characterized as unidirectional current transmission. A first end of the sixth transistor T6 is connected to the first resistor Rl, a second end of the sixth transistor T6 is connected to ground, and a control end of the sixth transistor T6 is connected to the second end of the sixth transistor T6. A first end of the seventh transistor T7 is connected to the second resistor R2, a second end of the seventh transistor T7 is connected to ground, and a control end of the seventh transistor T7 is connected to the second end of the seventh transistor T7. Figure 8

[0082] In Figure 6 and Figure 8 the embodiment shown, the temperature compensation current Ic and the change of temperature Figure 9 In the temperature range less than the fixed temperature point Ta, the weighted value of the first voltage V1 of the first branch is 100%, and the temperature compensation current Ic is equal to the current flowing through the first branch. In the temperature range greater than the fixed temperature point Ta, the weighted value of the second voltage V2 of the second branch can be 100%, and the temperature compensation current Ic is equal to the current flowing through the second branch.

[0083] In this way, by switching the module 160 to switch the second input end of the amplifier 140 to be connected to the first branch 120 or the second branch 130, the switching of the two temperature coefficient currents can be conveniently realized, and different temperature compensation currents can be output.

[0084] Next, referring to Figure 10 , Figure 10 the voltage at the second input end of the amplifier 140 is a weighted sum of part of the first voltage V1 and part of the second voltage V2, and the switching module 160 changes the mixing ratio of the first voltage V1 of the first branch 120 and the second voltage V2 of the second branch 130 to realize temperature compensation current regulation.

[0085] ​The switching module 160 can include a plurality of voltage division unit groups 161, each of which includes a first voltage division element 161A and a second voltage division element 161B, and a switching unit. The input end of the first voltage division element 161A is connected to the output end (i.e., the drain) of the second transistor T2, and the output end of the first voltage division element 161A is connected to the second input end of the amplifier 140. In addition, the input end of the second voltage division element 161B is connected to the output end of the third transistor T3, and the output end of the second voltage division element 161B is connected to the second input end of the amplifier 140. The ratio of the voltage division coefficients of the first voltage division element 161A and the second voltage division element 161B of the plurality of voltage division unit groups is different, and different weighting sums of the partial first voltage V1 and the partial second voltage V2 can be achieved through the plurality of voltage division unit groups. For example, the voltage at the second input end of the amplifier 140 is a weighted sum of the partial first voltage V1 after the first voltage V1 is divided by the first voltage division element and the partial second voltage V2 after the second voltage V2 is divided by the second voltage division element 161B, that is, in formulas 1 and 2, a1, a2, b1, b2 are all less than 1 and greater than 0, and a1:a2≠b1:b2. The switching unit is configured to select different voltage division unit groups to be turned on to the second input end of the amplifier, and also switch different weighting ratios.

[0086] For example, as shown in FIG. 8, the switching module 160 includes two voltage division unit groups 161 (two groups of first voltage division elements 161A and second voltage division elements 161B). In each voltage division unit group, the first voltage division element 161A includes a third resistor R3, and the second voltage division element 161B includes a fourth resistor R4. In another voltage division unit group, the first voltage division element 161A includes a fifth resistor R5, and the second voltage division element 161B includes a sixth resistor R6. Figure 10 The switching unit includes a third switch S3 and a fourth switch S4, a fifth switch S5 and a sixth switch S6. The temperature coefficients of the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 are all zero temperature coefficients, which avoids affecting the temperature compensation current Ic. The control ends of the third switch S3 and the fourth switch S4 are both connected to one output end of the comparator 150, and the control ends of the fifth switch S5 and the sixth switch S6 are both connected to the other output end of the comparator 150. The control ends of the third switch S3 and the fourth switch S4 receive a first control signal Ctrl1 and respond to the first control signal Ctrl1 being in a conductive state; the control ends of the fifth switch S5 and the sixth switch S6 receive a second control signal Ctrl2 and respond to the second control signal Ctrl2 being in a conductive state.

[0087]

[0088] ​The third resistor R3 and the third switch S3 are connected in series between the first branch 120 and the second input terminal of the amplifier 140, and the fourth resistor R4 and the fourth switch S4 are connected in series between the second branch 130 and the second input terminal of the amplifier 140. The fifth resistor R5 and the fifth switch S5 are connected in series between the first branch 120 and the second input terminal of the amplifier 140, and the sixth resistor R6 and the sixth switch S6 are connected in series between the second branch 130 and the second input terminal of the amplifier 140.

[0089] The resistance ratio (R3:R4) of the third resistor R3 and the fourth resistor R4 is different from the resistance ratio (R5:R6) of the fifth resistor R5 and the sixth resistor R6, so that two different voltage weighting ratios can be switched. When the comparator 150 flips at the fixed temperature point Ta, the contribution of the first branch and the second branch to the temperature compensation current Ic is changed.

[0090] For example, when the size of the second unidirectional conduction unit U2 is equal to the size of the third unidirectional conduction unit U3, the resistance of the first resistor R1 and the resistance of the second resistor R2 are equal at the fixed temperature point Ta, the resistance of the first resistor R1 is greater than the resistance of the second resistor R2 in the temperature range less than the fixed temperature point Ta, the current of the first branch 120 is less than the current of the second branch 130, and the first voltage V1 is less than the second voltage V2. As shown in FIG. 4, the first voltage V1 is less than the second voltage V2 in the temperature range less than the fixed temperature point Ta. Figure 11AAs shown, the comparator 150 outputs the first control signal Ctrl1 and the second control signal Ctrl2, the third switch S3 and the fourth switch S4 of the switching module 160 are turned on in response to the first control signal Ctrl1, the first branch 120 can be connected to the second input terminal of the amplifier 140 through the third resistor R3, and the second branch 130 can be connected to the second input terminal of the amplifier 140 through the fourth resistor R4; and the fifth switch S5 and the sixth switch S6 of the switching module 160 are turned off in response to the second control signal Ctrl2, the path of the fifth resistor R5 and the sixth resistor R6 is not connected. In this way, the third resistor R3 and the fourth resistor R4 form a resistor voltage dividing network, and the resistance ratio of the third resistor R3 and the fourth resistor R4 represents the mixing ratio of the first voltage V1 of the first branch 120 and the second voltage V2 of the second branch 130. For example, the resistance ratio of the third resistor R3 and the fourth resistor R4 is 1 / 2; the weighted proportion of the first voltage V1 is 1 / 3, and the weighted proportion of the second voltage V2 is 2 / 3, and the weighted sum of 1 / 3 of the first voltage V1 and 2 / 3 of the second voltage V2 is output to the second input terminal of the amplifier 140. Wherein, the temperature change rule of the node B coupled by the switching module 160 is consistent with the temperature characteristics of the first resistor R1 in the first branch 120. And the first input terminal of the amplifier 140 is coupled with the node A, and the second input terminal of the amplifier 140 is coupled with the node B, the amplifier 140 can clamp the voltages of the node A and the node B, so that the voltages of the node A and the node B are consistent, and the temperature characteristics are consistent. By connecting the first voltage V1 of the first branch 120 and the second voltage V2 of the second branch 130 to the feedback loop of the amplifier 140 in the resistance ratio of the third resistor R3 and the fourth resistor R4, the temperature compensation current Ic output from the fourth transistor T4 is related to the temperature characteristics of the first resistor R1 and the second resistor R2, and the degree of correlation is consistent with the resistance ratio of the third resistor R3 and the fourth resistor R4.

[0091] When the temperature reaches the fixed temperature point Ta, the resistance of the first resistor R1 is equal to the resistance of the second resistor R2, the current of the first branch 120 is equal to the current of the second branch 130, and the first voltage V1 is equal to the second voltage V2. As shown in FIG. 2, the temperature compensation current Ic output from the fourth transistor T4 is equal to the current of the first branch 120 and the second branch 130, and the temperature characteristics of the first resistor R1 and the second resistor R2 are consistent with the temperature characteristics of the third resistor R3 and the fourth resistor R4. Figure 11BAs shown, the comparator 150 outputs the first control signal Ctrl1 and the second control signal Ctrl2, the fifth switch S5 and the sixth switch S6 of the switching module 160 are turned on in response to the second control signal Ctrl2, the first branch 120 can be connected to the second input terminal of the amplifier 140 through the fifth resistor R5, and the second branch 130 can be connected to the second input terminal of the amplifier 140 through the sixth resistor R6. And the third switch S3 and the fourth switch S4 of the switching module 160 are turned off in response to the first control signal Ctrl1, the path of the third resistor R3 and the fourth resistor R4 is not connected. In this way, the fifth resistor R5 and the sixth resistor R6 are connected in parallel, and the resistance ratio of the fifth resistor R5 and the sixth resistor R6 represents the mixing ratio of the first voltage V1 of the first branch 120 and the second voltage V2 of the second branch 130. For example, the resistance ratio of the fifth resistor R5 and the sixth resistor R6 is 2 / 1; the weighted proportion of the first voltage V1 is 2 / 3, and the weighted proportion of the second voltage V2 is 1 / 3, and the weighted sum of 2 / 3 of the first voltage V1 and 1 / 3 of the second voltage V2 is output to the second input terminal of the amplifier 140. Wherein, the temperature change rule of the node B coupled by the switching module 160 is consistent with the temperature characteristic of the first resistor R1 in the first branch 120. And the first input terminal of the amplifier 140 is coupled with the node A, and the second input terminal of the amplifier 140 is coupled with the node B, and the amplifier 140 can clamp the voltages of the node A and the node B, so that the voltages of the node A and the node B are consistent, and the temperature characteristics are consistent. By connecting the first voltage V1 of the first branch 120 and the second voltage V2 of the second branch 130 to the feedback loop of the amplifier 140 in the resistance ratio of the fifth resistor R5 and the sixth resistor R6, the temperature compensation current Ic output from the fourth transistor T4 is related to the temperature characteristics of the first resistor R1 and the second resistor R2, and the correlation is consistent with the resistance ratio of the fifth resistor R5 and the sixth resistor R6.

[0092] And in the temperature range greater than the fixed temperature point, the resistance of the first resistor R1 is less than the resistance of the second resistor R2, the current of the first branch 120 is equal to the current of the second branch 130, and the first voltage V1 is greater than the second voltage V2. As Figure 11B As shown, the comparator 150 outputs the first control signal Ctrl1 and the second control signal Ctrl2, the switching module 160 continues to keep the first branch 120 connected to the second input terminal of the amplifier 140 through the fifth resistor R5, and the second branch 130 connected to the second input terminal of the amplifier 140 through the sixth resistor R6. And the third switch S3 and the fourth switch S4 of the switching module 160 are turned off in response to the first control signal Ctrl1, the path of the third resistor R3 and the fourth resistor R4 is not connected. And continue to output the weighted sum of the partial first voltage V1 and the partial second voltage V2 satisfying the resistance relationship of the fifth resistor R5 and the sixth resistor R6 to the second input terminal of the amplifier 140.

[0093] exist Figure 10 、 Figure 11A and Figure 11B In the embodiment shown, the relationship between the temperature compensation current Ic and the temperature is Figure 12 As shown in the figure, within the temperature range below the fixed temperature point Ta, the weighted value of the first voltage V1 of the first branch is 1 / 3, and the weighted value of the second voltage V2 of the second branch is 2 / 3; within the temperature range above the fixed temperature point Ta, the weighted value of the first voltage V1 of the first branch is 2 / 3, and the weighted value of the second voltage V2 of the second branch is 1 / 3, thus achieving a nonlinear temperature compensation current.

[0094] Based on this, the voltages output by the multiple branches can be connected to the amplifier 140 in different mixing ratios according to different temperature variation ranges through the switching module 160, thereby performing different degrees of current compensation for the nonlinearly varying current. Specifically, by setting the resistance ratio of the third resistor R3 to the fourth resistor R4, and the resistance ratio of the fifth resistor R5 to the sixth resistor R6, the effect of changing the mixing ratio of the first voltage V1 and the second voltage V2 is achieved. In addition, by adjusting the temperature coefficient of the first resistor R1 and the temperature coefficient of the second resistor R2, the flexibility of the temperature compensation current is improved, which is conducive to further improving the accuracy of the current compensation.

[0095] In other embodiments, when the size of the second unidirectional conduction unit U2 is larger than the size of the third unidirectional conduction unit U3, and the resistance of the first resistor R1 is greater than the resistance of the second resistor R2 at the fixed temperature point Ta, or when the size of the second unidirectional conduction unit U2 is smaller than the size of the third unidirectional conduction unit U3, and the resistance of the first resistor R1 is smaller than the resistance of the second resistor R2 at the fixed temperature point Ta, when the temperature reaches the fixed temperature point Ta, the voltage between the first voltage V1 and the second voltage V2 can also trigger the first control signal Ctrl1 and the second control signal Ctrl2 output by the comparator 150 to change, so as to control the different voltage dividing units entering the switching module 160, thereby adjusting the weighted ratio.

[0096] In the above example, the voltage dividing unit in the switching module 160 uses resistors to achieve the voltage dividing effect. The voltage dividing unit can also use other electronic components or circuits such as programmable voltage dividers to achieve the voltage dividing effect. The example provided in this application does not impose specific restrictions on this and can be set according to the circuit structure.

[0097] In the above example, the switch unit uses multiple independent switches, and each voltage dividing element corresponds to an independent switch. In other embodiments, the third resistor R3 and the fourth resistor R4 can share a switch, and the fifth resistor R5 and the sixth resistor R6 can share a switch. For example, the third resistor R3 and the fourth resistor R4 are connected in series between the output end of the second transistor T2 and the output end of the third transistor T3, the middle node of the third resistor R3 and the fourth resistor R4 is connected to the second input end of the amplifier through a shared switch; the fifth resistor R5 and the sixth resistor R6 are connected in series between the output end of the second transistor T2 and the output end of the third transistor T3, and the middle node of the fifth resistor R5 and the sixth resistor R6 is connected to the second input end of the amplifier through a shared switch.

[0098] The above merely describes the embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A temperature compensation circuit, characterized in that: include: A current mirror comprising a first transistor, a second transistor, a third transistor, and a fourth transistor; a control terminal of the first transistor, a control terminal of the second transistor, a control terminal of the third transistor, and a control terminal of the fourth transistor are coupled together; a current at an output terminal of the second transistor, a current at an output terminal of the third transistor, and a current at an output terminal of the fourth transistor are all proportional to a current at the output terminal of the first transistor; A first branch includes a first resistor connected to an output terminal of the second transistor; The second branch includes a second resistor, wherein the second resistor is connected to the output terminal of the third transistor; wherein the temperature coefficient of the first resistor is different from the temperature coefficient of the second resistor; an amplifier comprising a first input terminal, a second input terminal and an output terminal; the first input terminal is connected to the output terminal of the first transistor; the output terminal of the amplifier is connected to the control terminal of the first transistor; a comparator, wherein two input terminals of the comparator are respectively connected to the output terminal of the second transistor and the output terminal of the third transistor, and the comparator is configured to respectively obtain a first voltage output by the output terminal of the second transistor and a second voltage output by the output terminal of the third transistor, and compare them; The switching module is connected to the output terminal of the comparator and is configured to change the weighted ratio of the first voltage to the second voltage based on the comparison result and output it to the second input terminal.

2. The temperature compensation circuit according to claim 1, wherein: The switching module is configured to selectively connect the output terminal of the second transistor to the second input terminal of the amplifier, or connect the output terminal of the third transistor to the second input terminal of the amplifier.

3. The temperature compensation circuit according to claim 2, wherein: The switching module includes a first switch and a second switch; A first terminal of the first switch is connected to the output terminal of the second transistor, a second terminal of the first switch is connected to the second input terminal, and a control terminal of the first switch is connected to an output terminal of the comparator; the first switch is configured to connect the second input terminal to the output terminal of the second transistor in response to a first control signal output by the comparator being in an on state, and a voltage at the second input terminal is equal to the first voltage; A first end of the second switch is connected to the output end of the third transistor, a second end of the second switch is connected to the second input end, and a control end of the second switch is connected to the other output end of the comparator; the second switch is configured to be in an on state in response to a second control signal output by the comparator, connect the second input end to the output end of the third transistor, and the voltage of the second input end is equal to the second voltage.

4. The temperature compensation circuit according to claim 1, wherein: The switching module includes a plurality of voltage dividing unit groups and a switch unit, and the voltage dividing unit group includes a first voltage dividing element and a second voltage dividing element; The input end of the first voltage divider element is connected to the output end of the second transistor, the output end of the first voltage divider element is connected to the second input end of the amplifier, the input end of the second voltage divider element is connected to the output end of the third transistor, and the output end of the second voltage divider element is connected to the second input end of the amplifier; The ratios of the voltage dividing coefficients of the first voltage dividing element and the second voltage dividing element of the plurality of voltage dividing unit groups are different; The switch unit is configured to select and connect different groups of the voltage dividing units to the second input terminal of the amplifier.

5. The temperature compensation circuit according to claim 4, wherein: The switching module includes: two voltage dividing unit groups; in one voltage dividing unit group, the first voltage dividing element includes a third resistor, and the second voltage dividing element includes a fourth resistor; in the other voltage dividing unit group, the first voltage dividing element includes a fifth resistor, and the second voltage dividing element includes a sixth resistor; The switch unit includes: a third switch and a fourth switch, wherein the third resistor and the third switch are connected in series between the first branch and the second input terminal, and the fourth resistor and the fourth switch are connected in series between the second branch and the second input terminal; the control terminals of the third switch and the fourth switch are both connected to one output terminal of the comparator, and are configured to connect the second input terminal to the output terminal of the second transistor and the output terminal of the third transistor in response to the first control signal output by the comparator being in an on state; a fifth switch and a sixth switch, wherein the fifth resistor and the fifth switch are connected in series between the first branch and the second input terminal, and the sixth resistor and the sixth switch are connected in series between the second branch and the second input terminal; control terminals of the fifth switch and the sixth switch are both connected to the other output terminal of the comparator, and the fifth switch and the sixth switch are configured to connect the second input terminal to the output terminal of the second transistor and the output terminal of the third transistor in response to the second control signal output by the comparator being in an on state; A resistance ratio between the third resistor and the fourth resistor is different from a resistance ratio between the fifth resistor and the sixth resistor.

6. The temperature compensation circuit according to claim 5, characterized in that: The temperature coefficient of the third resistor, the temperature coefficient of the fourth resistor, the temperature coefficient of the fifth resistor, and the temperature coefficient of the sixth resistor are all zero temperature coefficients.

7. The temperature compensation circuit according to claim 1, wherein: The aspect ratio of the first transistor, the aspect ratio of the second transistor, and the aspect ratio of the third transistor are the same.

8. The temperature compensation circuit according to claim 1, wherein: The input terminal of the first transistor, the input terminal of the second transistor, the input terminal of the third transistor, and the input terminal of the fourth transistor are respectively connected to the first power supply voltage terminal; The temperature compensation circuit further includes a first unidirectional conductive unit, one end of the first unidirectional conductive unit is connected to the first input end, and the other end of the first unidirectional conductive unit is connected to the second power supply voltage end; The first branch further includes a second unidirectional conductive unit, a first end of the second unidirectional conductive unit is connected to the first resistor, and the other end of the second unidirectional conductive unit is connected to the second power supply voltage terminal; The second branch further includes a third unidirectional conductive unit, one end of the third unidirectional conductive unit is connected to the second resistor, and the other end of the third unidirectional conductive unit is connected to the second power supply voltage terminal.

9. The temperature compensation circuit according to claim 8, characterized in that: The second unidirectional conductive unit, the third unidirectional conductive unit, the first resistor, and the second resistor satisfy the following relationship: The size of the second unidirectional conductive unit is larger than that of the third unidirectional conductive unit, and at a fixed temperature point, the resistance value of the first resistor is larger than the resistance value of the second resistor; The size of the second unidirectional conductive unit is equal to the size of the third unidirectional conductive unit, and at the fixed temperature point, the resistance value of the first resistor is equal to the resistance value of the second resistor; The size of the second one-way conducting unit is smaller than that of the third one-way conducting unit. At the fixed temperature point, the resistance value of the first resistor is smaller than the resistance value of the second resistor.

10. The temperature compensation circuit according to claim 8, wherein: The temperature coefficient of the first resistor is a zero temperature coefficient, and the temperature coefficient of the second resistor is a positive temperature coefficient or a negative temperature coefficient; Alternatively, the temperature coefficient of the first resistor and the temperature coefficient of the second resistor are both positive temperature coefficients or negative temperature coefficients.

11. The temperature compensation circuit according to claim 1, wherein: The amplifier includes at least one of a five-tube amplifier, a sleeve amplifier and a folding amplifier.

12. The temperature compensation circuit according to claim 1, wherein: The comparator includes a static comparator or a dynamic comparator.

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