Constant voltage differential tracking circuit, constant voltage differential detection system, switching charging chip and electronic device

Abstract

The application belongs to the field of electronic circuits, and provides a constant voltage difference tracking circuit, a constant voltage difference detection system, a switching charging chip and an electronic device. The first current module in the constant voltage difference tracking circuit outputs a first current and mirrors the first current to a second current module, so that the second current module outputs a second current. When a first switch module is turned on and a second switch module is turned off, a first resistor, a second resistor, a third resistor and a fourth resistor connected in series in turn generate an output voltage according to an input voltage and the first current. When the first switch module is turned off and the second switch module is turned on, the first resistor, the second resistor, the third resistor and the fourth resistor connected in series in turn generate an output voltage according to the input voltage and the second current. The application splits each of the original two voltage dividing resistors into two resistors, does not need to add an additional resistor device, and does not increase the chip area overhead. In combination with two small currents, the application skillfully uses the equivalent circuit of Thevenin theorem to realize the relationship of y = ax ± b .

Description

Technical Field

[0001] This application belongs to the field of electronic circuit technology, and in particular relates to a constant differential voltage tracking circuit, a constant differential voltage detection system, a switching charging chip, and an electronic device. Background Technology

[0002] As people's demand for fast charging, miniaturization, and high-safety energy replenishment continues to increase, the requirements for heat dissipation performance of devices are also becoming increasingly stringent. In various application scenarios that require efficient conversion of higher input voltages to battery operating voltages, switching charging has become the mainstream technology solution. Unlike linear charging, which is suitable for low-current, low-cost scenarios, switching charging has the core advantage of high efficiency. It utilizes components such as inductors and capacitors to achieve energy conversion, achieving an efficiency of over 90% and generating significantly less heat than linear charging. Switching charging is mainly applied in three major scenarios: 1. Portable consumer electronics, covering charging scenarios for devices such as smartphones, tablets, laptops, and TWS (True Wireless Stereo) earphones. This scenario addresses the contradiction between large-capacity batteries and compact device bodies; 2. Industrial and security fields, covering charging scenarios for devices such as walkie-talkies, explosion-proof equipment, security cameras, and portable industrial scanners. This scenario can adapt to a wide range of input voltages while meeting strict heat dissipation requirements; 3. High-power energy storage and power fields, covering charging scenarios for devices such as power banks, energy storage power supplies, power tools, and drones. In switching charging systems, it is often necessary to perform constant differential voltage tracking on certain voltages before sending them to a subsequent constant differential voltage detection circuit for detection and judgment. This requires implementing a linear function in circuit form. The relation, where 0 <a<1。

[0003] However, currently regarding The implementation of relational circuits at the level of most structures is quite complex, which often consumes a large chip area and power consumption, which is not conducive to the miniaturization and low power consumption requirements of switching charging chips. This is a problem that needs to be optimized. Summary of the Invention

[0004] This application provides a constant differential voltage tracking circuit, a constant differential voltage detection system, a switching charging chip, and an electronic device, which can solve the problems of existing constant differential voltage tracking circuits having large chip area and high power consumption, and being unable to adapt to the miniaturization and low power consumption requirements of switching charging chips.

[0005] In a first aspect, embodiments of this application provide a constant differential voltage tracking circuit, including a first current module, a first switch module, a second switch module, a second current module, a first voltage divider resistor, and a second voltage divider resistor; the first voltage divider resistor includes a first resistor and a second resistor; the second voltage divider resistor includes a third resistor and a fourth resistor; a first terminal of the first switch module is connected to a first terminal of the first current module; a second terminal of the first switch module is connected to the first terminals of the third resistor and the fourth resistor, respectively, with the connection node of the three serving as a first node; a first terminal of the second switch module is connected to the first terminals of the first resistor and the second resistor, respectively, with the connection node of the three serving as a second node; a second terminal of the first resistor serves as an input terminal for receiving an input voltage; a second terminal of the second resistor is connected to the second terminal of the third resistor, with the connection node of the two serving as an output terminal; a second terminal of the second switch module is connected to a first terminal of the second current module; a second terminal of the first current module is connected to a second terminal of the second current module; a third terminal of the second current module and a second terminal of the fourth resistor are used for grounding; The first current module outputs a first current and mirrors the first current to the second current module, causing the second current module to output a second current. When the first switch module is turned on and the second switch module is turned off, the first current flows into the first node, and the first resistor, the second resistor, the third resistor, and the fourth resistor connected in series in sequence generate an output voltage based on the input voltage and the first current. When the first switch module is turned off and the second switch module is turned on, the second current flows out of the second node, and the first resistor, the second resistor, the third resistor, and the fourth resistor connected in series in sequence generate an output voltage based on the input voltage and the second current.

[0006] In one possible implementation of the first aspect, the sum of the resistance values ​​of the first resistor and the second resistor is equal to the resistance value of the first voltage divider resistor, and the sum of the resistance values ​​of the third resistor and the fourth resistor is equal to the resistance value of the second voltage divider resistor.

[0007] In one possible implementation of the first aspect, the first current module includes a first bias current source, a first transistor, a second transistor, a third transistor, and a fourth transistor; the input terminal of the first bias current source, the source of the third transistor, and the source of the fourth transistor receive a power supply voltage; the output terminal of the first bias current source is connected to the drain of the first transistor, the gate of the first transistor, the gate of the second transistor, and a second terminal of the second current module, respectively; the drain of the second transistor is connected to the drain of the third transistor, the gate of the third transistor, and the gate of the fourth transistor, respectively; the drain of the fourth transistor is connected to a first terminal of the first switching module; and the sources of the first transistor and the second transistor are both grounded.

[0008] In one possible implementation of the first aspect, the second current module includes a fifth transistor; the gate of the fifth transistor is connected to a second terminal of the first current module; the drain of the fifth transistor is connected to a second terminal of the second switching module; and the source of the fifth transistor is grounded.

[0009] In one possible implementation of the first aspect, the first switching module includes a sixth transistor; the gate of the sixth transistor receives a first signal; the source of the sixth transistor is connected to a first terminal of the first current module; the drain of the sixth transistor is connected to the first terminal of the third resistor and the first terminal of the fourth resistor, respectively, and the connection node of the three is used as the first node.

[0010] In one possible implementation of the first aspect, the second switching module includes a seventh transistor; the gate of the seventh transistor receives a second signal; the drain of the seventh transistor is connected to the first terminal of the first resistor and the first terminal of the second resistor, respectively, and the connection node of the three is used as a second node; the source of the seventh transistor is connected to the first terminal of the second current module.

[0011] In one possible implementation of the first aspect, when the first signal is low and the second signal is low, the sixth transistor is turned on and the seventh transistor is turned off; when the first signal is high and the second signal is high, the sixth transistor is turned off and the seventh transistor is turned on.

[0012] Secondly, embodiments of this application provide a constant differential pressure detection system, including the constant differential pressure tracking circuit described in any one of the first aspects.

[0013] Thirdly, embodiments of this application provide a switching charging chip, including the constant differential pressure detection system described in the second aspect.

[0014] Fourthly, embodiments of this application provide an electronic device including the switching charging chip described in the third aspect.

[0015] The beneficial effects of the embodiments in this application compared with the prior art are: This application provides a constant differential voltage tracking circuit, including a first current module, a first switch module, a second switch module, a second current module, a first voltage divider resistor, and a second voltage divider resistor. The first voltage divider resistor includes a first resistor and a second resistor; the second voltage divider resistor includes a third resistor and a fourth resistor. The first terminal of the first switch module is connected to the first terminal of the first current module. The second terminal of the first switch module is connected to the first terminals of the third resistor and the fourth resistor, respectively, and the connection node of the three is called the first node. The first terminal of the second switch module is connected to the first terminals of the first resistor and the second resistor, respectively, and the connection node of the three is called the second node. The second terminal of the first resistor serves as the input terminal for receiving input voltage. The second terminal of the second resistor is connected to the second terminal of the third resistor, and the connection node of the two serves as the output terminal. The second terminal of the second switch module is connected to the first terminal of the second current module. The second terminal of the first current module is connected to the second terminal of the second current module. The third terminal of the second current module and the second terminal of the fourth resistor are used for grounding.

[0016] The first current module outputs a first current and mirrors it to the second current module, causing the second current module to output a second current. When the first switching module is on and the second switching module is off, the first current flows into the first node. The first, second, third, and fourth resistors, connected in series, generate the output voltage based on the input voltage and the first current. The expression for the output voltage is obtained using the equivalent circuit derived from Thevenin's theorem. ,in, Indicates the output voltage. Indicates the input voltage. This indicates the resistance value of the first resistor. This indicates the resistance value of the second resistor. This indicates the resistance value of the third resistor. This indicates the resistance value of the fourth resistor. This represents the first current. As can be seen from the above expression, As the dependent variable, The independent variable is the coefficient of the linear term. constant term , achieved The relational expression.

[0017] Similarly, when the first switching module is open and the second switching module is open, the second current flows out of the second node. The first, second, third, and fourth resistors connected in series in sequence generate the output voltage based on the input voltage and the second current. The expression for the output voltage is obtained using the equivalent circuit derived from Thevenin's theorem: ,in, This represents the second current. As can be seen from the above expression, As the dependent variable, The independent variable is the coefficient of the linear term. constant term , achieved The relational expression.

[0018] The constant differential pressure tracking circuit provided in this application implements... The relation, where 0 <a<1,b> 0.

[0019] In summary, the constant voltage difference tracking circuit provided in this application splits the original two voltage divider resistors into two resistors each, eliminating the need for additional resistors and thus avoiding increased chip area overhead. Simultaneously, by utilizing two very small currents (i.e., the first current and the second current), it cleverly employs the equivalent circuit based on Thevenin's theorem, achieving circuit-level performance. The relationship is shown in the figure. Compared with existing technical solutions, this application has the advantages of small area and low power consumption, which can well meet the requirements of miniaturization and low power consumption of switching charging chips.

[0020] It is understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a circuit connection diagram of an existing constant differential pressure tracking circuit; Figure 2 This is a schematic diagram of a constant differential pressure tracking circuit provided in an embodiment of this application; Figure 3 This is a circuit connection diagram of a constant differential pressure tracking circuit provided in an embodiment of this application.

[0023] In the diagram: 10, first current module; 20, first switch module; 30, second switch module; 40, second current module. Detailed Implementation

[0024] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0025] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0026] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0027] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [the described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [the described condition or event] is detected," or "in response to detection of [the described condition or event]."

[0028] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0030] Figure 1 The circuit structure of an existing constant differential voltage tracking circuit is shown, such as... Figure 1As shown, due to the virtual short-circuit principle of operational amplifier EA (i.e., the voltages at the two input terminals of the operational amplifier are approximately equal), the voltage V_A1 at node A1 is equal to the voltage V_A2 at node A2, expressed as V_A1 = V_A2 = ,in, This indicates the input voltage. Figure 1 In this configuration, transistors NM1 and NM2 are the same size and function as current mirrors. Therefore, the current flowing through transistor NM2 is equal to the current flowing through transistor NM1, and both are equal to the bias current. Ibias0 Ultimately, the output voltage can be obtained. expression As can be seen from the expression, a linear relation in one variable is ultimately realized, where, It is the independent variable. It is the dependent variable; the coefficient of the linear term. constant term .

[0031] Figure 1 The circuit structure in the chip has obvious drawbacks. Because the structure uses an error amplifier EA, which is a standard control loop, stability compensation is essential. This significantly increases the chip's area and power consumption, which is not conducive to the chip's miniaturization and low power consumption requirements.

[0032] To address the aforementioned issues, this application provides a constant voltage difference tracking circuit that splits the original two voltage divider resistors into two separate resistors, eliminating the need for additional resistors and thus avoiding increased chip area overhead. Simultaneously, by cleverly utilizing the equivalent circuit based on Thevenin's theorem, and incorporating two very small currents, it achieves circuit-level performance. The relationship is shown in the figure. Compared with existing technical solutions, this application has the advantages of small area and low power consumption, which can well meet the requirements of miniaturization and low power consumption of switching charging chips.

[0033] To illustrate the technical solution described in this application, specific embodiments are provided below.

[0034] Figure 2 A schematic diagram of a constant differential pressure tracking circuit according to an embodiment of this application is shown. Figure 2As shown, the constant voltage difference tracking circuit includes a first current module 10, a first switch module 20, a second switch module 30, a second current module 40, a first voltage divider resistor, and a second voltage divider resistor. The first voltage divider resistor includes a first resistor R1 and a second resistor R2; the second voltage divider resistor includes a third resistor R3 and a fourth resistor R4. The first terminal of the first switch module 20 is connected to the first terminal of the first current module 10. The second terminal of the first switch module 20 is connected to the first terminals of the third resistor R3 and the fourth resistor R4, respectively, and the connection node of the three is called the first node B1. The first terminal of the second switch module 30 is connected to the first terminals of the first resistor R1 and the second resistor R2, respectively, and the connection node of the three is called the second node B2. The second terminal of the first resistor R1 serves as the input terminal for receiving the input voltage. V_X The second terminal of the second resistor R2 is connected to the second terminal of the third resistor R3. The connection point between them serves as the output terminal, used to generate the output voltage. V_Y The second terminal of the second switch module 30 is connected to the first terminal of the second current module 40; the second terminal of the first current module 10 is connected to the second terminal of the second current module 40; the third terminal of the second current module 40 and the second terminal of the fourth resistor R4 are used for grounding GND.

[0035] Specifically, the first current module 10 is used to output the first current. I 1, and the first current I 1. Mirror the current to the second current module 40, so that the second current module 40 outputs the second current. I 2. When the first switch module 20 is turned on and the second switch module 30 is turned off, the first current... I 1. The first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4, connected in series in sequence, flow into the first node B1 according to the input voltage. V_X and the first current I 1. Generate output voltage V_Y The output voltage is obtained from the equivalent circuit based on Thevenin's theorem. V_Y The expression: ,in, Indicates the output voltage. Indicates the input voltage. This indicates the resistance value of the first resistor R1. This indicates the resistance value of the second resistor, R2. This indicates the resistance value of the third resistor, R3. This indicates the resistance value of the fourth resistor, R4. This represents the first current. As can be seen from the above expression, As the dependent variable, The independent variable is the coefficient of the linear term. constant term , achieved The relational expression.

[0036] Similarly, when the first switch module 20 is open and the second switch module 30 is open, the second current... I 2. The first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4, connected in series in sequence, are adjusted according to the input voltage. V_X Second current I 2. Generate output voltage V_Y The output voltage is obtained from the equivalent circuit based on Thevenin's theorem. V_Y The expression: ,in, This represents the second current. As can be seen from the above expression, As the dependent variable, The independent variable is the coefficient of the linear term. constant term , achieved The relationship is described. The constant differential pressure tracking circuit provided in this application implements... The relation, where 0 <a<1,b> 0.

[0037] This application splits the original two voltage divider resistors into two separate resistors, eliminating the need for additional resistors and thus avoiding increased chip area overhead; it also accommodates two very small currents (i.e., the first current). I 1 and second current I 2) By cleverly utilizing the equivalent circuit of Thevenin's theorem, the circuit was implemented at the circuit level. The relationship is shown in the figure. Compared with existing technical solutions, this application has the advantages of small area and low power consumption, which can well meet the requirements of miniaturization and low power consumption of switching charging chips.

[0038] In summary, the constant differential voltage tracking circuit provided in this application solves the problems of existing constant differential voltage tracking circuits having large chip area and high power consumption, which cannot meet the miniaturization and low power consumption requirements of switching charging chips.

[0039] It should be noted that when splitting the original two voltage divider resistors into two resistors each, the following can be done: the sum of the resistance values ​​of the first resistor R1 and the second resistor R2 equals the resistance value of the first voltage divider resistor, and the sum of the resistance values ​​of the third resistor R3 and the fourth resistor R4 equals the resistance value of the second voltage divider resistor.

[0040] In one embodiment of this application, such as Figure 3As shown, the first current module 10 includes a first bias current source, a first transistor M1, a second transistor M2, a third transistor M3, and a fourth transistor M4; the input terminal of the first bias current source, the source of the third transistor M3, and the source of the fourth transistor M4 receive the power supply voltage VDD; the output terminal of the first bias current source is connected to the drain of the first transistor M1, the gate of the first transistor M1, the gate of the second transistor M2, and the second terminal of the second current module 40, respectively; the drain of the second transistor M2 is connected to the drain of the third transistor M3, the gate of the third transistor M3, and the gate of the fourth transistor M4, respectively; the drain of the fourth transistor M4 is connected to the first terminal of the first switching module 20; the sources of the first transistor M1 and the second transistor M2 are both grounded to GND.

[0041] Specifically, the first bias current source is used to provide the first bias current. Ibias1 The third transistor M3 and the fourth transistor M4 are the same size and function as current mirrors here. Similarly, the first transistor M1 and the second transistor M2 are also the same size and function as current mirrors here. Therefore, the current flowing through the fourth transistor M4 is equal to the current flowing through the first transistor M1 and is also equal to the first bias current. Ibias1 The current flowing through the fourth transistor M4 is the first current. I 1, i.e., the first current I 1 equals the first bias current Ibias1 .

[0042] In one embodiment of this application, such as Figure 3 As shown, the second current module 40 includes a fifth transistor M5; the gate of the fifth transistor M5 is connected to the second terminal of the first current module 10, specifically to the gate of the first transistor M1 in the first current module 10; the drain of the fifth transistor M5 is connected to the second terminal of the second switching module 30; and the source of the fifth transistor M5 is used to ground GND.

[0043] Specifically, the fifth transistor M5 has the same dimensions as the first transistor M1. Its function here is to mirror the current; therefore, the current flowing through the fifth transistor M5 is equal to the current flowing through the first transistor M1 and is also equal to the first bias current. Ibias1 The current flowing through the fifth transistor M5 is the second current. I 2, i.e., the second current I 2 equals the first bias current Ibias1 .

[0044] In one embodiment of this application, such as Figure 3As shown, the first switching module 20 includes a sixth transistor M6; the gate of the sixth transistor M6 receives the first signal PEN_B; the source of the sixth transistor M6 is connected to the first terminal of the first current module 10, specifically to the drain of the fourth transistor M4 in the first current module 10; the drain of the sixth transistor M6 is connected to the first terminal of the third resistor R3 and the first terminal of the fourth resistor R4 respectively, and the connection node of the three is the first node B1.

[0045] The second switching module 30 includes a seventh transistor M7; the gate of the seventh transistor M7 receives a second signal NEN; the drain of the seventh transistor M7 is connected to the first terminal of the first resistor R1 and the first terminal of the second resistor R2, and the connection node of the three is the second node B2; the source of the seventh transistor M7 is connected to the first terminal of the second current module 40, specifically to the drain of the fifth transistor M5 in the second current module 40.

[0046] Specifically, when the first signal PEN_B is low and the second signal NEN is low, the sixth transistor M6 is turned on and the seventh transistor M7 is turned off. At this time, the first current... I 1. The current flows into the first node B1. According to Thevenin's theorem, the equivalent circuit yields the expression for the output voltage: ,in, Indicates the output voltage. Indicates the input voltage. This indicates the resistance value of the first resistor. This indicates the resistance value of the second resistor. This indicates the resistance value of the third resistor. This indicates the resistance value of the fourth resistor. This represents the first current. As can be seen from the above expression, As the dependent variable, The independent variable is the coefficient of the linear term. constant term , achieved The relational expression.

[0047] When the first signal PEN_B is high and the second signal NEN is high, the sixth transistor M6 is off and the seventh transistor M7 is on. At this time, the second current... I 2. The output voltage flows out from the second node B2. According to Thevenin's theorem, the equivalent circuit expression for the output voltage is obtained as follows: ,in, This represents the second current. As can be seen from the above expression, As the dependent variable, The independent variable is the coefficient of the linear term. constant term , achieved The relational expression.

[0048] It should be noted that the first signal PEN_B and the second signal NEN can be the same signal or two different signals. Both signals are existing signals inside the switching charging chip.

[0049] From the above derivation, it can be concluded that the constant differential pressure tracking circuit provided in this application can achieve... The relation, where 0 <a<1,b> 0.

[0050] It should be noted that, Figure 3 In the first transistor M1, the second transistor M2, the third transistor M3, the fourth transistor M4, and the fifth transistor M5 are used to provide the first current. I 1 and second current I 2, Figure 3 This is an exemplary structure and is not intended to be unique. Any device structure that can achieve the same current output function can be used as an alternative.

[0051] In summary, the constant voltage difference tracking circuit provided in this application splits the original two voltage divider resistors into two resistors each, eliminating the need for additional resistors and thus avoiding increased chip area overhead; simultaneously, it works in conjunction with two very small currents (i.e., the first current). I 1 and second current I 2) By cleverly utilizing the equivalent circuit of Thevenin's theorem, the circuit was implemented at the circuit level. The relationship is shown in the figure. Compared with existing technical solutions, this application has the advantages of small area and low power consumption, which can well meet the requirements of miniaturization and low power consumption of switching charging chips.

[0052] This application also provides a constant differential pressure detection system, including the constant differential pressure tracking circuit described above. Since the constant differential pressure detection system provided in this application adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be elaborated further here.

[0053] This application also provides a switching charging chip, including the constant differential voltage detection system described above. Since the switching charging chip provided in this application adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be elaborated further here.

[0054] This application also provides an electronic device including the aforementioned switching charging chip. Since the electronic device provided in this application adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be elaborated upon further here.

[0055] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0056] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A constant differential pressure tracking circuit, characterized in that, The system includes a first current module, a first switch module, a second switch module, a second current module, a first voltage divider resistor, and a second voltage divider resistor. The first voltage divider resistor comprises a first resistor and a second resistor. The second voltage divider resistor comprises a third resistor and a fourth resistor. A first terminal of the first switch module is connected to a first terminal of the first current module. A second terminal of the first switch module is connected to the first terminals of both the third and fourth resistors, with the connection point of these three resistors forming a first node. A first terminal of the second switch module is connected to the first terminals of both the first and second resistors, with the connection point of these three resistors forming a second node. A second terminal of the first resistor serves as an input terminal for receiving input voltage. A second terminal of the second resistor is connected to the second terminal of the third resistor, with the connection point of these two resistors forming an output terminal. A second terminal of the second switch module is connected to a first terminal of the second current module. A second terminal of the first current module is connected to a second terminal of the second current module. A third terminal of the second current module and a second terminal of the fourth resistor are used for grounding. The first current module is used to output a first current and mirror the first current to the second current module, so that the second current module outputs a second current; when the first switch module is turned on and the second switch module is turned off, the first current flows into the first node, and the first resistor, the second resistor, the third resistor and the fourth resistor connected in series in sequence generate an output voltage according to the input voltage and the first current; When the first switch module is off and the second switch module is on, the second current flows out of the second node, and the first resistor, the second resistor, the third resistor and the fourth resistor connected in series in sequence generate an output voltage according to the input voltage and the second current.

2. The constant differential pressure tracking circuit according to claim 1, characterized in that, The sum of the resistance values ​​of the first resistor and the second resistor is equal to the resistance value of the first voltage divider resistor, and the sum of the resistance values ​​of the third resistor and the fourth resistor is equal to the resistance value of the second voltage divider resistor.

3. The constant differential pressure tracking circuit according to claim 1 or 2, characterized in that, The first current module includes a first bias current source, a first transistor, a second transistor, a third transistor, and a fourth transistor; the input terminal of the first bias current source, the source of the third transistor, and the source of the fourth transistor receive a power supply voltage; the output terminal of the first bias current source is connected to the drain of the first transistor, the gate of the first transistor, the gate of the second transistor, and the second terminal of the second current module, respectively; the drain of the second transistor is connected to the drain of the third transistor, the gate of the third transistor, and the gate of the fourth transistor, respectively; the drain of the fourth transistor is connected to the first terminal of the first switching module; the sources of the first transistor and the sources of the second transistor are both grounded.

4. The constant differential pressure tracking circuit according to claim 1 or 2, characterized in that, The second current module includes a fifth transistor; the gate of the fifth transistor is connected to the second terminal of the first current module; the drain of the fifth transistor is connected to the second terminal of the second switching module; and the source of the fifth transistor is grounded.

5. The constant differential pressure tracking circuit according to claim 1 or 2, characterized in that, The first switching module includes a sixth transistor; the gate of the sixth transistor receives a first signal; the source of the sixth transistor is connected to the first terminal of the first current module; the drain of the sixth transistor is connected to the first terminal of the third resistor and the first terminal of the fourth resistor respectively, and the connection node of the three is the first node.

6. The constant differential pressure tracking circuit according to claim 5, characterized in that, The second switching module includes a seventh transistor; the gate of the seventh transistor receives a second signal; the drain of the seventh transistor is connected to the first end of the first resistor and the first end of the second resistor respectively, and the connection node of the three is used as a second node; the source of the seventh transistor is connected to the first end of the second current module.

7. The constant differential pressure tracking circuit according to claim 6, characterized in that, When the first signal is low and the second signal is low, the sixth transistor is turned on and the seventh transistor is turned off; when the first signal is high and the second signal is high, the sixth transistor is turned off and the seventh transistor is turned on.

8. A constant differential pressure detection system, characterized in that, Includes the constant differential pressure tracking circuit as described in any one of claims 1-7.

9. A switching charging chip, characterized in that, Includes the constant differential pressure detection system as described in claim 8.

10. An electronic device, characterized in that, Includes the switching charging chip as described in claim 9.

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