Current detection circuit with low temperature coefficient

Abstract

The invention provides a low-temperature-coefficient current detection circuit which comprises a current module, an adjusting module and a comparison module, the adjusting module comprises an adjusting unit, the first output end of the adjusting unit is connected to a first resistor, and the second output end of the adjusting unit is grounded; the input end of the first switch tube M1 is connected to power supply voltage VDD, the output end is connected to the first input end of the adjusting unit and the comparison module, and the control end is connected to the current module; the input end of the second switch tube M2 is connected to the power supply voltage VDD, the output end is connected to the second input end of the adjusting unit and the comparison module, and the control end is connected to the control end of the first switch tube M1; the adjusting unit is set to be capable of adjusting the voltage magnitude relation between the output end of the first switching tube M1 and the output end of the second switching tube M2 according to the magnitude relation between the to-be-detected current ID of the to-be-detected circuit and the threshold current ID0, and then the level of the output voltage VO of the output end of the current detection circuit is adjusted. And the sensitivity of the threshold current ID0 to the temperature is reduced along with the rise of the temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit detection, and in particular to a current detection circuit with a low temperature coefficient. Background Art

[0002] Figure 1 The topological structure diagram of the power supply circuit in the prior art is shown. Figure 1 The power supply circuit includes a power supply control chip U0 and a resistor RS, wherein the resistor RS is connected in series in the current detection branch of the current to be detected as a current detection resistor. The power supply control chip U0 includes an operational amplifier A1 and a logic circuit. The operational amplifier A1 detects the current I0 by detecting the voltage across the resistor R0. At the same time, the operational amplifier A1 outputs a corresponding control signal to the logic circuit according to the voltage across the resistor R0, thereby realizing functions such as power control and current limiting.

[0003] However, both the operational amplifier A1 or the logic circuit inside the power control chip U0 and the external resistor RS are affected by temperature. Figure 2 FIG. 1 is a schematic diagram showing how the threshold current of the current I0 to be measured varies with temperature in the prior art. Figure 2 It can be seen that in the prior art, the temperature coefficient of the threshold current can reach several mA / K or even higher, thereby greatly reducing the accuracy of the current detection circuit and the safety and reliability of the power control chip U0. Summary of the invention

[0004] The embodiment of the present invention provides a current sensing circuit with a low temperature coefficient, which can effectively reduce the influence of temperature on the current sensing circuit, thereby improving the accuracy of the current sensing circuit and the safety and reliability of a power control chip.

[0005] According to a first aspect of the present invention, a current detection circuit with a low temperature coefficient is provided, which is used to detect a current signal of a circuit to be tested, wherein the circuit to be tested includes a first resistor R1, and the current detection circuit includes a current module, a regulating module and a comparing module, wherein the regulating module includes: an adjusting unit, comprising a first input terminal, a second input terminal, a first output terminal and a second output terminal, wherein the first output terminal is connected to one terminal of a first resistor R1, the second output terminal is grounded, and the other terminal of the first resistor R1 is grounded; The first switch tube M1 has an input terminal connected to the power supply voltage VDD, an output terminal connected to the first input terminal of the regulating unit and the comparison module, and a control terminal connected to the current module; The second switch tube M2 has an input terminal connected to the power supply voltage VDD, an output terminal connected to the second input terminal of the regulating unit and the comparison module, and a control terminal connected to the control terminal of the first switch tube M1; Among them, the adjustment unit is configured to adjust the voltage magnitude relationship between the output end of the first switch tube M1 and the output end of the second switch tube M2 according to the magnitude relationship between the measured current ID of the measured circuit and the threshold current ID0, thereby adjusting the level of the output voltage VO at the output end of the current detection circuit. The sensitivity of the threshold current ID0 to temperature decreases as the temperature increases.

[0006] In a possible implementation, the rate formula of the threshold current ID0 changing with the temperature T is: ; Wherein, P is a constant, a represents the temperature coefficient of the first resistor R1, and a is greater than 0, T0 represents the room temperature, Indicates the rate at which the threshold current changes with temperature.

[0007] In a possible implementation, the adjustment unit includes a second resistor R2 and a third resistor R3 connected in series, a third switch tube M3 and a fourth resistor R4 connected in sequence, and a fourth switch tube M4 and a fifth resistor R5 connected in sequence; The control end of the third switch tube M3 is connected to the control end of the fourth switch tube M4 and is connected between the second resistor R2 and the third resistor R3. The end of the fourth resistor R4 away from the third switch tube M3 serves as the first output end. The end of the fifth resistor R5 away from the fourth switch tube M4 serves as the second output end. One end of the second resistor R2 away from the third resistor R3 is connected to the input end of the third switch tube M3 and serves as the first input end. One end of the third resistor R3 away from the second resistor R2 is connected to the input end of the fourth switch tube M4 and serves as the second input end.

[0008] In a possible implementation, in the current module, the power supply voltage VDD is grounded through the fifth switch tube M5 and the first transistor Q1 in sequence; the power supply voltage VDD is also grounded through the sixth switch tube M6, the sixth resistor R6 and the second transistor Q2 in sequence; The control end of the fifth switch tube M5 is connected to the control end of the sixth switch tube M6 and is merged into the control end of the first switch tube M1. The first transistor Q1 and the second transistor Q2 are both diode-connected.

[0009] In a possible implementation, the power supply voltage VDD is further grounded through the seventh switch tube M7, the eighth switch tube M8 and the first current source B1 in sequence; the power supply voltage VDD is further grounded through the ninth switch tube M9, the tenth switch tube M10 and the first current source B1 in sequence; The seventh switch tube M7 is connected to the control end of the ninth switch tube M9 and is incorporated into the output end of the ninth switch tube M9. The control end of the eighth switch tube M8 is connected to the first node C1 between the fifth switch tube M5 and the first transistor Q1. The control end of the tenth switch tube M10 is connected to the second node C2 between the sixth switch tube M6 and the sixth resistor R6. The third node E between the seventh switch tube M7 and the eighth switch tube M8 is connected to the control end of the fifth switch tube M5.

[0010] In a possible implementation, the fifth switch tube M5, the sixth switch tube M6, the first switch tube M1 and the second switch tube M2 form a 1:1:M:M current mirror structure; The number ratio of the first transistor Q1 to the second transistor Q2 is 1:N; The seventh switch tube M7 and the ninth switch tube M9 form a 1:1 current mirror structure.

[0011] In a possible implementation, in the rate formula of the threshold current ID0 changing with the temperature T, the formula of the constant P is: ; in, represents the resistance value of the first resistor R1 at room temperature, Indicates the thermal voltage value of the first transistor Q1 and the second transistor Q2 at room temperature.

[0012] In a possible implementation, the comparison module includes a comparison unit and an output unit; In the comparison unit, the power supply voltage VDD is connected to the ground through the second current source B2, the eleventh switch tube M11 and the seventh resistor R7 in sequence, and the power supply voltage VDD is also connected to the ground through the second current source B2, the twelfth switch tube M12 and the eighth resistor R8 in sequence; the control end of the eleventh switch tube M11 is connected to the output end of the second switch tube M2; the control end of the twelfth switch tube M12 is connected to the output end of the first switch tube M1; The fourth node F1 between the eleventh switch tube M11 and the seventh resistor R7 and the fifth node F2 between the twelfth switch tube M12 and the eighth resistor R8 are both connected to the output unit; the output unit is configured to adjust the level of the output voltage VO in the output unit according to the size relationship between the fourth node F1 and the fifth node F2.

[0013] In a possible implementation, in the output unit, the power supply voltage VDD is grounded through the third current source B3, the thirteenth switch tube M13 and the fourteenth switch tube M14 in sequence; the power supply voltage VDD is also grounded through the third current source B3, the fifteenth switch tube M15 and the sixteenth switch tube M16 in sequence; the control end of the thirteenth switch tube M13 is connected to the fourth node F1, and the control end of the fifteenth switch tube M15 is connected to the fifth node F2; the control end of the fourteenth switch tube M14 is connected to the input end of the fourteenth switch tube M14, and the control end of the sixteenth switch tube M16 is connected to the input end of the sixteenth switch tube M16; The power supply voltage VDD is also grounded through the seventeenth switch tube M17 and the eighteenth switch tube M18 in sequence; the power supply voltage VDD is also grounded through the nineteenth switch tube M19 and the twentieth switch tube M20 in sequence; the control end of the seventeenth switch tube M17 is connected to the control end of the nineteenth switch tube M19 and is merged into the output end of the seventeenth switch tube M17; the control end of the eighteenth switch tube M18 is connected to the control end of the fourteenth switch tube M14, and the control end of the twentieth switch tube M20 is connected to the control end of the sixteenth switch tube M16; The output end of the current detection circuit is located between the nineteenth switch tube M19 and the twentieth switch tube M20.

[0014] In a possible implementation, the fourteenth switch tube M14 and the eighteenth switch tube M18 form a 1:1 current mirror structure; The sixteenth switch tube M16 and the twentieth switch tube M20 form a 1:1 current mirror structure; The seventeenth switch tube M17 and the nineteenth switch tube M19 form a 1:1 current mirror structure.

[0015] In a possible implementation, when the measured current ID is less than the threshold current ID0, the output voltage VO is a first level signal; When the measured current ID is greater than the threshold current ID0, the output voltage VO is a second level signal; A first level corresponding to the first level signal is lower than a second level corresponding to the second level signal.

[0016] In a second aspect, the present invention further provides a power supply circuit, comprising a circuit to be tested, a logic circuit and the current detection circuit as described above; In the circuit to be tested, the input power source VIN is grounded through the first power switch tube Mp1, the second power switch tube Mp2 and the first resistor R1 in sequence; the control end of the first power switch tube Mp1 and the control end of the second power switch tube Mp2 are both connected to the logic circuit; The circuit to be tested further includes a first inductor L1 and a first capacitor C1, one end of the first inductor L1 is connected between the first power switch tube Mp1 and the second power switch tube Mp2, and the other end is connected to the output end VOUT of the power supply circuit; one end of the first capacitor C1 is connected to the output end VOUT of the power supply circuit, and the other end is grounded; The current detection circuit is connected to the logic circuit and is used to output a voltage signal to the logic circuit; The current detection circuit is connected to a sixth node A between the first resistor R1 and the second power switch tube Mp2, and the current detection circuit is grounded.

[0017] In a possible implementation manner, when the first power switch tube Mp1 is turned on and the second power switch tube Mp2 is turned off, the output voltage VO is a first level signal.

[0018] In a possible implementation, when the first power switch tube Mp1 is turned off and the second power switch tube Mp2 is turned on, the voltage relationship between the output end of the first switch tube M1 and the output end of the second switch tube M2 is adjusted according to the relationship between the measured current ID of the measured circuit and the threshold current ID0, thereby adjusting the level of the output voltage VO of the current detection circuit.

[0019] According to the solution of the present invention, when the first power switch tube Mp1 is turned on and the second power switch tube Mp2 is turned off, no current flows through the second power switch tube Mp2, and the current to be measured ID does not exist at this time. When the first power switch tube Mp1 is turned off and the second power switch tube Mp2 is turned on, there is a freewheeling current flowing from PGND to the first inductor L1, and the freewheeling current is the current to be measured ID. At this time, the adjustment unit adjusts the voltage between the output end of the first switch tube M1 and the output end of the second switch tube M2 according to the magnitude relationship between the current to be measured ID and the threshold current ID0, thereby adjusting the level of the output voltage VO. Since the threshold current ID0 is less sensitive to temperature as the temperature increases, and the operating temperature of the power supply circuit is relatively high under most working conditions, the threshold current ID0 can remain stable when the temperature changes, thereby enabling the current detection circuit to maintain high detection accuracy and stability when the temperature changes, effectively reducing the influence of temperature on the current detection performance.

[0020] Furthermore, the present invention adopts a positive temperature coefficient resistor outside the power control chip and is designed in coordination with the internal circuit of the power control chip, so that while being able to realize basic functions such as current detection, the threshold current of the current detection circuit also has a lower temperature coefficient, thereby effectively reducing the impact of temperature changes on detection accuracy. At the same time, the present invention adopts optimized designs such as current mirrors, resistor networks, and multi-stage switch tube control to improve the stability and sensitivity of current detection.

[0021] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A topological structure diagram of a power supply circuit in the prior art is shown; Figure 2 A schematic diagram showing the change of the threshold value of the current I0 to be measured with the temperature in the prior art is shown; Figure 3 A topological structure diagram of a power supply circuit according to an embodiment of the present invention is shown; Figure 4 A topological structure diagram of a current sensing circuit with a low temperature coefficient according to an embodiment of the present invention is shown; Figure 5 A topological structure diagram of a current sensing circuit with a low temperature coefficient according to another embodiment of the present invention is shown; Figure 6 A schematic diagram showing the variation of the threshold current of a current detection circuit with a low temperature coefficient according to an embodiment of the present invention with respect to temperature; Figure 7 A schematic diagram showing the rate of change of the threshold current of a current detection circuit with a low temperature coefficient according to an embodiment of the present invention as the temperature changes. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some structures related to the present application are shown in the accompanying drawings, rather than all structures. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0024] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0025] Figure 3 FIG. 2 shows a topological structure diagram of a power supply circuit according to an embodiment of the present invention. Figure 3 As shown, the power supply circuit includes a circuit to be tested and a power supply control chip U1. The power supply control chip U1 includes a logic circuit and a current detection circuit. In the circuit to be tested, the input power supply VIN is grounded through the first power switch tube Mp1, the second power switch tube Mp2 and the first resistor R1 in sequence. The control end of the first power switch tube Mp1 and the control end of the second power switch tube Mp2 are both connected to the logic circuit. The circuit to be tested also includes a first inductor L1 and a first capacitor C1, one end of the first inductor L1 is connected between the first power switch tube Mp1 and the second power switch tube Mp2, and the other end is connected to the output end VOUT of the power supply circuit. One end of the first capacitor C1 is connected to the output end VOUT of the power supply circuit, and the other end is grounded. The current detection circuit is connected to the logic circuit for outputting a voltage signal to the logic circuit. The current detection circuit is also connected to the sixth node A between the first resistor R1 and the second power switch tube Mp2, and the current detection circuit is grounded. In one embodiment, the first resistor R1 is a metal resistor with a positive temperature coefficient.

[0026] In this embodiment, the working principle of the power supply circuit is as follows: when the first power switch tube Mp1 is turned on and the second power switch tube Mp2 is turned off, the power current flows through the first power switch tube Mp1 and flows into the first inductor L1. At this time, the second power switch tube Mp2 is in the off state and no current flows. When the first power switch tube Mp1 is turned off and the second power switch tube Mp2 is turned on, no current flows through the first power switch tube Mp1, and a freewheeling current flows from PGND to the first inductor L1 through the second power switch tube Mp2 and the first resistor R1. At this time, the power current is positively correlated with the freewheeling current, that is, the larger the power current, the larger the freewheeling current. Therefore, detecting the freewheeling current is equivalent to detecting the power current. In other words, by detecting the voltage across the first resistor R1 through the current detection circuit, the current detection of the power supply circuit can be realized.

[0027] According to the solution of the embodiment of the present invention, the terminal voltage of the first resistor R1 is detected by the current detection circuit to detect the current flowing through the second power switch tube Mp2. At the same time, the current detection circuit outputs a corresponding control signal to the logic circuit according to the terminal voltage of the first resistor R1. The logic circuit controls the on and off of the first power switch tube Mp1 and the second power switch tube Mp2 according to the control signal, thereby realizing functions such as power control and current limiting.

[0028] In one embodiment, the second power switch tube Mp2 can be replaced by a diode, one end of which is connected to the output end of the first power switch tube Mp1, and the other end is grounded through the first resistor R1. At this time, the diode is not connected to the logic circuit, and it turns on and off automatically according to the working state of the circuit.

[0029] Figure 4 FIG. 2 shows a topological structure diagram of a current sensing circuit with a low temperature coefficient according to an embodiment of the present invention. Figure 4 As shown, the current detection circuit is used to detect the current signal of the circuit to be tested, and the circuit to be tested includes a first resistor R1. It can be understood that Figure 3 In the illustrated embodiment, the current signal of the circuit to be tested is the current signal flowing through the second power switch tube Mp2 , and the current signal can be obtained by detecting the terminal voltage of the first resistor R1 .

[0030] The current detection circuit includes a current module, a regulating module and a comparison module, and the output end of the current detection circuit is set in the comparison module. The regulating module includes a regulating unit, a first switch tube M1 and a second switch tube M2. The regulating unit has a first input end, a second input end, a first output end and a second output end, the first output end is connected to one end of the first resistor R1, the second output end is grounded, and the other end of the first resistor R1 is grounded. The input end of the first switch tube M1 is connected to the power supply voltage VDD, the output end is connected to the first input end of the regulating unit and the comparison module, and the control end is connected to the current module. The input end of the second switch tube M2 is connected to the power supply voltage VDD, the output end is connected to the second input end of the regulating unit and the comparison module, and the control end is connected to the control end of the first switch tube M1. Among them, the regulating unit is configured to be able to adjust the voltage magnitude relationship between the output end of the first switch tube M1 and the output end of the second switch tube M2 according to the magnitude relationship between the measured current ID of the circuit to be tested and the threshold current ID0, thereby adjusting the level of the output voltage VO of the output end of the current detection circuit, and the threshold current ID0 is less sensitive to temperature as the temperature increases.

[0031] It can be seen from the working principle of the above power supply circuit that when the first power switch tube Mp1 is turned on and the second power switch tube Mp2 is turned off, no current flows through the second power switch tube Mp2, and there is no current to be measured ID at this time. When the first power switch tube Mp1 is turned off and the second power switch tube Mp2 is turned on, there is a freewheeling current flowing from PGND to the first inductor L1, and the freewheeling current is the current to be measured ID. At this time, the adjustment unit adjusts the voltage between the output end of the first switch tube M1 and the output end of the second switch tube M2 according to the magnitude relationship between the current to be measured ID and the threshold current ID0, thereby adjusting the level of the output voltage VO. Since the threshold current ID0 is less sensitive to temperature as the temperature increases, and the operating temperature of the power supply circuit is relatively high under most working conditions, the threshold current ID0 can remain stable when the temperature changes, thereby enabling the current detection circuit to maintain high detection accuracy and stability when the temperature changes, effectively reducing the influence of temperature on the current detection performance.

[0032] In some embodiments, the rate at which the threshold current ID0 changes with temperature T is expressed as follows: ; Wherein, P is a constant, a represents the temperature coefficient of the first resistor R1, and a is greater than 0, T0 represents the room temperature, Indicates the rate at which the threshold current changes with temperature. In one embodiment, P is a constant determined by calibration.

[0033] From this formula, we can see that since P, T0 and a are all constants, It is inversely proportional to the square of the temperature T, that is, as the temperature increases, the sensitivity of the threshold current ID0 to temperature gradually decreases. Under most working conditions, the operating temperature of the power supply circuit is relatively high. Therefore, the threshold current ID0 of the current detection circuit in the embodiment of the present invention has a relatively low temperature coefficient, which can effectively reduce the influence of temperature on the current detection circuit, thereby improving the accuracy of the current detection circuit and the safety and reliability of the power control chip.

[0034] Figure 5 FIG. 2 shows a topological structure diagram of a current sensing circuit with a low temperature coefficient according to another embodiment of the present invention. Figure 5As shown, the regulating unit includes a second resistor R2 and a third resistor R3 connected in series, a third switch tube M3 and a fourth resistor R4 connected in sequence, and a fourth switch tube M4 and a fifth resistor R5 connected in sequence. The control end of the third switch tube M3 is connected to the control end of the fourth switch tube M4 and is incorporated between the second resistor R2 and the third resistor R3, and an end of the fourth resistor R4 away from the third switch tube M3 serves as a first output end. An end of the fifth resistor R5 away from the fourth switch tube M4 serves as a second output end. An end of the second resistor R2 away from the third resistor R3 is connected to the input end of the third switch tube M3 and serves as a first input end, and an end of the third resistor R3 away from the second resistor R2 is connected to the input end of the fourth switch tube M4 and serves as a second input end.

[0035] In one embodiment, the resistance of the fourth resistor R4 is greater than the resistance of the fifth resistor R5.

[0036] In this embodiment, the working principle of the regulation module includes two parts: when the first power switch tube Mp1 of the power circuit is turned on and the second power switch tube Mp2 is turned off, and when the first power switch tube Mp1 of the power circuit is turned off and the second power switch tube Mp2 is turned on.

[0037] When the first power switch tube Mp1 of the power supply circuit is turned on and the second power switch tube Mp2 is turned off, the working principle of the regulation module is as follows: at this time, no current flows through the first resistor R1, and the voltage of the sixth node A is PGND. The control terminal voltages of the third switch tube M3 and the fourth switch tube M4 are pulled up through the second resistor R2 and the third resistor R3, respectively, and the output terminal voltages of the third switch tube M3 and the fourth switch tube M4 are pulled down through the fourth resistor R4 and the fifth resistor R5, respectively, so the third switch tube M3 and the fourth switch tube M4 are turned on. At this time, if the current flowing through the third switch tube M3 is equal to the current flowing through the fourth switch tube M4, and because the resistance value of the fourth resistor R4 is greater than the resistance value of the fifth resistor R5, the output terminal voltage Vs3 of the third switch tube M3 should be greater than the output terminal voltage Vs4 of the fourth switch tube M4, and the voltage difference Vgs3 between the control terminal and the output terminal of the third switch tube M3 should be smaller than the voltage difference Vgs4 between the control terminal and the output terminal of the fourth switch tube M4, and the current flowing through the third switch tube M3 should be smaller than the current flowing through the fourth switch tube M4, which is inconsistent. If the current flowing through the third switch tube M3 is greater than the current flowing through the fourth switch tube M4, since the resistance value of the fourth resistor R4 is greater than the resistance value of the fifth resistor R5, the output terminal voltage Vs3 of the third switch tube M3 should be greater than the output terminal voltage Vs4 of the fourth switch tube M4, and the voltage difference Vgs3 between the control terminal and the output terminal of the third switch tube M3 should be less than the voltage difference Vgs4 between the control terminal and the output terminal of the fourth switch tube M4, and the current flowing through the third switch tube M3 should also be less than the current flowing through the fourth switch tube M4, which is inconsistent. Therefore, at this time, the current flowing through the third switch tube M3 must be less than the current flowing through the fourth switch tube M4, and the output terminal voltage Vs3 of the third switch tube M3 must be greater than the output terminal voltage Vs4 of the fourth switch tube M4, so that the voltage difference Vgs3 between the control terminal and the output terminal of the third switch tube M3 is less than the voltage difference Vgs4 between the control terminal and the output terminal of the fourth switch tube M4, and the current flowing through the third switch tube M3 is less than the current flowing through the fourth switch tube M4, which is consistent.

[0038] When the circuit is stable, the current module makes the current I1 flowing through the first switch tube M1 equal to the current I2 flowing through the second switch tube M2. Therefore, the second resistor R2 and the third resistor R3 generate a current flowing from the input end of the third switch tube M3 to the input end of the fourth switch tube M4, so that the voltage at the output end of the first switch tube M1 is greater than the voltage at the output end of the second switch tube M2.

[0039] When the first power switch tube Mp1 of the power supply circuit is turned off and the second power switch tube Mp2 is turned on, the working principle of the regulation module is as follows: at this time, the measured current ID flows from PGND to the sixth node A through the first resistor R1, and the voltage of the sixth node A is , and the output terminal voltage of the third switch tube M3 is positively correlated with the voltage of the sixth node A. From the analysis of the working principle of the regulation module when the first power switch tube Mp1 of the power supply circuit is turned on and the second power switch tube Mp2 is turned off, it can be seen that when the voltage of the sixth node A is PGND, the voltage at the output terminal of the first switch tube M1 is greater than the voltage at the output terminal of the second switch tube M2. If it is assumed that the current ID to be measured is ∞, the voltage of the sixth node A is -∞, and the voltage at the output end of the third switch tube M3 is also -∞. At this time, the voltage difference Vgs3 between the control end and the output end of the third switch tube M3 is greater than the voltage difference Vgs4 between the control end and the output end of the fourth switch tube M4. The current flowing through the third switch tube M3 is greater than the current flowing through the fourth switch tube M4. Since the current I1 flowing through the first switch tube M1 is equal to the current I2 flowing through the second switch tube M2, the second resistor R2 and the third resistor R3 generate a current flowing from the input end of the fourth switch tube M4 to the input end of the third switch tube M3, so that the voltage at the output end of the first switch tube M1 is less than the voltage at the output end of the second switch tube M2.

[0040] It can be seen that as the measured current ID increases, the output terminal voltage Vs3 of the third switch tube M3 will gradually decrease, and the voltage of the output terminal of the first switch tube M1 will gradually change from being greater than the voltage of the output terminal of the second switch tube M2 to being less than the voltage of the output terminal of the second switch tube M2. Therefore, in the present invention, when the measured current ID reaches the threshold current ID0, the voltage of the output terminal of the first switch tube M1 is equal to the voltage of the output terminal of the second switch tube M2, and the current flowing through the third switch tube M3, the current flowing through the first switch tube M1, the current flowing through the second switch tube M2, and the current flowing through the fourth switch tube M4 are all equal, and the output terminal voltage Vs3 of the third switch tube M3 is equal to the output terminal voltage Vs4 of the fourth switch tube M4, so the voltage difference Vgs3 between the control terminal and the output terminal of the third switch tube M3 is equal to the voltage difference Vgs4 between the control terminal and the output terminal of the fourth switch tube M4. It can be seen that the output terminal voltage Vs3 of the third switch tube M3 is equal to the voltage of the fourth resistor R4 plus the voltage of the sixth node A. At the same time, the output terminal voltage Vs3 of the third switch tube M3 is also equal to the output terminal voltage Vs4 of the fourth switch tube M4, that is, the voltage of the fifth resistor R5, that is, , thus the threshold current .

[0041] From the above analysis, it can be seen that when the current to be measured ID is less than the threshold current ID0, that is, When the voltage Vs3 at the output end of the third switch tube M3 is greater than the voltage Vs4 at the output end of the fourth switch tube M4, the voltage difference Vgs3 between the control end and the output end of the third switch tube M3 is less than the voltage difference Vgs4 between the control end and the output end of the fourth switch tube M4, a current is generated in the second resistor R2 and the third resistor R3 that flows from the output end of the third switch tube M3 to the output end of the fourth switch tube M4, and the voltage at the output end of the first switch tube M1 is greater than the voltage at the output end of the second switch tube M2.

[0042] When the current to be measured ID is greater than the threshold current ID0, that is, When the voltage at the output end of the third switch tube M3 is less than the voltage at the output end of the fourth switch tube M4, the voltage difference Vgs3 between the control end and the output end of the third switch tube M3 is greater than the voltage difference Vgs4 between the control end and the output end of the fourth switch tube M4, a current is generated in the second resistor R2 and the third resistor R3, flowing from the input end of the fourth switch tube M4 to the input end of the third switch tube M3, and the voltage at the output end of the first switch tube M1 is less than the voltage at the output end of the second switch tube M2.

[0043] In summary, the regulating unit can, when the first power switch tube Mp1 of the power supply circuit is turned off and the second power switch tube Mp2 is turned on, make the voltage at the output end of the first switch tube M1 greater than the voltage at the output end of the second switch tube M2 when ID<ID0, and make the voltage at the output end of the first switch tube M1 less than the voltage at the output end of the second switch tube M2 when ID>ID0. It can also, when the first power switch tube Mp1 of the power supply circuit is turned on and the second power switch tube Mp2 is turned off, that is, when there is no current to be measured ID, make the voltage at the output end of the first switch tube M1 greater than the voltage at the output end of the second switch tube M2.

[0044] In some embodiments, the comparison module includes a comparison unit and an output unit. The comparison unit includes a second current source B2, an eleventh switch tube M11, a twelfth switch tube M12, a seventh resistor R7 and an eighth resistor R8. The resistance of the seventh resistor R7 is equal to the resistance of the eighth resistor R8. In the comparison unit, the power supply voltage VDD is connected to the ground through the second current source B2, the eleventh switch tube M11 and the seventh resistor R7 in sequence, and the power supply voltage VDD is also connected to the ground through the second current source B2, the twelfth switch tube M12 and the eighth resistor R8 in sequence. The control end of the eleventh switch tube M11 is connected to the output end of the second switch tube M2, and the control end of the twelfth switch tube M12 is connected to the output end of the first switch tube M1. The fourth node F1 between the eleventh switch tube M11 and the seventh resistor R7 and the fifth node F2 between the twelfth switch tube M12 and the eighth resistor R8 are both connected to the output unit. The output unit is configured to adjust the level of the output voltage VO in the output unit according to the size relationship between the fourth node F1 and the fifth node F2.

[0045] In some embodiments, the output unit includes a third current source B3, a thirteenth switch tube M13, a fourteenth switch tube M14, a fifteenth switch tube M15, a sixteenth switch tube M16, a seventeenth switch tube M17, an eighteenth switch tube M18, a nineteenth switch tube M19, and a twentieth switch tube M20. In the output unit, the power supply voltage VDD is connected to the ground through the third current source B3, the thirteenth switch tube M13, and the fourteenth switch tube M14 in sequence, and the power supply voltage VDD is also connected to the ground through the third current source B3, the fifteenth switch tube M15, and the sixteenth switch tube M16 in sequence. The control end of the thirteenth switch tube M13 is connected to the fourth node F1, the control end of the fifteenth switch tube M15 is connected to the fifth node F2, the control end of the fourteenth switch tube M14 is connected to the input end of the fourteenth switch tube M14, and the control end of the sixteenth switch tube M16 is connected to the input end of the sixteenth switch tube M16. The power supply voltage VDD is also connected to the ground through the seventeenth switch tube M17 and the eighteenth switch tube M18 in sequence, and the power supply voltage VDD is also connected to the ground through the nineteenth switch tube M19 and the twentieth switch tube M20 in sequence. The control end of the seventeenth switch tube M17 is connected to the control end of the nineteenth switch tube M19 and is merged into the output end of the seventeenth switch tube M17, the control end of the eighteenth switch tube M18 is connected to the control end of the fourteenth switch tube M14, and the control end of the twentieth switch tube M20 is connected to the control end of the sixteenth switch tube M16. The output end of the current detection circuit is located between the nineteenth switch tube M19 and the twentieth switch tube M20.

[0046] In some embodiments, the fourteenth switch tube M14 and the eighteenth switch tube M18 form a 1:1 current mirror structure. The sixteenth switch tube M16 and the twentieth switch tube M20 form a 1:1 current mirror structure. The seventeenth switch tube M17 and the nineteenth switch tube M19 form a 1:1 current mirror structure.

[0047] In some embodiments, when the measured current ID is less than the threshold current ID0, the output voltage VO is a first level signal. When the measured current ID is greater than the threshold current ID0, the output voltage VO is a second level signal. The first level corresponding to the first level signal is lower than the second level corresponding to the second level signal.

[0048] by Figure 5 Taking the circuit structure of the comparison module of the embodiment of the present invention as an example, the working principle of the comparison module of the embodiment of the present invention is described below. The working principle of the comparison module includes two parts: when the current to be measured ID is less than the threshold current ID0 and when the current to be measured ID is greater than the threshold current ID0.

[0049] When the current ID to be measured is less than the threshold current ID0, it can be known from the above analysis that at this time, the voltage at the output end of the first switch tube M1 is greater than the voltage at the output end of the second switch tube M2. The working principle of the comparison module is: at this time, the voltage at the control end of the eleventh switch tube M11 is less than the voltage at the control end of the twelfth switch tube M12. Because the voltages at the input ends of the eleventh switch tube M11 and the twelfth switch tube M12 are both pulled up to the power supply voltage VDD through the second current source B2, the voltage difference between the control end and the input end of the eleventh switch tube M11 is greater than the voltage difference between the control end and the input end of the twelfth switch tube M12. Therefore, the current flowing through the eleventh switch tube M11 is greater than the current flowing through the twelfth switch tube M12. Since the seventh resistor R7 and the eighth resistor R8 have the same resistance value, the voltage at the fourth node F1 is greater than the voltage at the fifth node F2. Therefore, the voltage at the control end of the thirteenth switch tube M13 is greater than the voltage at the control end of the fifteenth switch tube M15. At this time, the input terminal voltages of the thirteenth switch tube M13 and the fifteenth switch tube M15 are pulled up to the power supply voltage VDD through the third current source B3. Therefore, the voltage difference between the control terminal and the input terminal of the fifteenth switch tube M15 is greater than the voltage difference between the control terminal and the input terminal of the thirteenth switch tube M13, and the current flowing through the tenth switch tube M15 is greater than the current flowing through the thirteenth switch tube M13. In addition, because the fourteenth switch tube M14 and the eighteenth switch tube M18 form a 1:1 current mirror structure, the sixteenth switch tube M16 and the twentieth switch tube M20 form a 1:1 current mirror structure, and the seventeenth switch tube M17 and the nineteenth switch tube M19 form a 1:1 current mirror structure. Therefore, the current flowing through the thirteenth switch tube M13 is equal to the current flowing through the nineteenth switch tube M19, the current flowing through the fifteenth switch tube M15 is equal to the current flowing through the twentieth switch tube M20, and the current flowing through the twentieth switch tube M20 is greater than the current flowing through the nineteenth switch tube M19, and the output voltage VO of the comparison module is a first level signal, that is, a low level signal.

[0050] When the current ID to be measured is greater than the threshold current ID0, it can be known from the above analysis that at this time, the voltage at the output end of the first switch tube M1 is less than the voltage at the output end of the second switch tube M2. The working principle of the comparison module is as follows: at this time, the voltage at the control end of the eleventh switch tube M11 is greater than the voltage at the control end of the twelfth switch tube M12. Since the voltages at the input ends of the eleventh switch tube M11 and the twelfth switch tube M12 are both pulled up to the power supply voltage VDD through the second current source B2, the voltage difference between the control end and the input end of the eleventh switch tube M11 is less than the voltage difference between the control end and the input end of the twelfth switch tube M12. Therefore, the current flowing through the eleventh switch tube M11 is less than the current flowing through the twelfth switch tube M12. Since the seventh resistor R7 and the eighth resistor R8 have the same resistance value, the voltage at the fourth node F1 is less than the voltage at the fifth node F2. Therefore, the voltage at the control end of the thirteenth switch tube M13 is less than the voltage at the control end of the fifteenth switch tube M15. At this time, the input terminal voltages of the thirteenth switch tube M13 and the fifteenth switch tube M15 are pulled up to the power supply voltage VDD through the third current source B3. Therefore, the voltage difference between the control terminal and the input terminal of the fifteenth switch tube M15 is smaller than the voltage difference between the control terminal and the input terminal of the thirteenth switch tube M13, and the current flowing through the tenth switch tube M15 is smaller than the current flowing through the thirteenth switch tube M13. In addition, because the fourteenth switch tube M14 and the eighteenth switch tube M18 form a 1:1 current mirror structure, the sixteenth switch tube M16 and the twentieth switch tube M20 form a 1:1 current mirror structure, and the seventeenth switch tube M17 and the nineteenth switch tube M19 form a 1:1 current mirror structure. Therefore, the current flowing through the thirteenth switch tube M13 is equal to the current flowing through the nineteenth switch tube M19, the current flowing through the fifteenth switch tube M15 is equal to the current flowing through the twentieth switch tube M20, and the current flowing through the twentieth switch tube M20 is less than the current flowing through the nineteenth switch tube M19, and the output voltage VO of the comparison module is a second level signal, that is, a high level signal.

[0051] From the above analysis, it can be seen that when the second power switch tube Mp2 is turned off, that is, no current flows, the output voltage VO of the current detection circuit is low. When the second power switch tube Mp2 is turned on, that is, current flows, and the current to be measured , that is, when the current to be measured ID does not reach the threshold current ID0, the output voltage VO of the current detection circuit is low. , that is, when the measured current ID reaches the threshold current ID0, the output voltage VO of the current detection circuit is high.

[0052] In some embodiments, the current module includes a fifth switch tube M5, a sixth switch tube M6, a first transistor Q1, a second transistor Q2, and a sixth resistor R6. In the current module, the power supply voltage VDD is connected to the ground through the fifth switch tube M5 and the first transistor Q1 in sequence, and the power supply voltage VDD is also connected to the ground through the sixth switch tube M6, the sixth resistor R6, and the second transistor Q2 in sequence. The control end of the fifth switch tube M5 is connected to the control end of the sixth switch tube M6 and is incorporated into the control end of the first switch tube M1, and the first transistor Q1 and the second transistor Q2 are both connected in a diode manner.

[0053] In some embodiments, the current module further includes a seventh switch tube M7, an eighth switch tube M8, a ninth switch tube M9, a tenth switch tube M10 and a first current source B1. In the current module, the power supply voltage VDD is grounded through the seventh switch tube M7, the eighth switch tube M8 and the first current source B1 in sequence. The power supply voltage VDD is also grounded through the ninth switch tube M9, the tenth switch tube M10 and the first current source B1 in sequence. The seventh switch tube M7 is connected to the control end of the ninth switch tube M9 and is incorporated into the output end of the ninth switch tube M9, the control end of the eighth switch tube M8 is connected to the first node C1 between the fifth switch tube M5 and the first triode Q1, the control end of the tenth switch tube M10 is connected to the second node C2 between the sixth switch tube M6 and the sixth resistor R6, and the third node E between the seventh switch tube M7 and the eighth switch tube M8 is connected to the control end of the fifth switch tube M5.

[0054] In some embodiments, the fifth switch tube M5, the sixth switch tube M6, the first switch tube M1 and the second switch tube M2 form a 1:1:M:M current mirror structure. The number ratio of the first transistor Q1 and the second transistor Q2 is 1:N. The seventh switch tube M7 and the ninth switch tube M9 form a 1:1 current mirror structure.

[0055] by Figure 5 Taking the circuit structure of the current module of the embodiment of the present invention as an example, the working principle of the current module of the embodiment of the present invention is described below.

[0056] When the circuit of the current module is powered on, the fifth switch tube M5, the sixth switch tube M6, the seventh switch tube M7, the eighth switch tube M8, the ninth switch tube M9 and the tenth switch tube M10 are all turned on and started. Because the fifth switch tube M5, the sixth switch tube M6, the first switch tube M1 and the second switch tube M2 form a current mirror structure of 1:1:M:M, the current flowing through the fifth switch tube M5 is equal to the current flowing through the sixth switch tube M6, that is, the current I3 flowing through the first triode Q1 is equal to the current I4 flowing through the second triode Q2. And because the number ratio of the first triode Q1 to the second triode Q2 is 1:N, the voltage difference between the base and the emitter of the first triode Q1 must be greater than the voltage difference between the base and the emitter of the second triode Q2. Furthermore, the first transistor Q1 and the second transistor Q2 are both diode-connected, and the bases are both grounded. Therefore, the emitter voltage VEQ1 of the first transistor Q1 must be greater than the emitter voltage VEQ2 of the second transistor Q2. At this time, the voltage of the first node C1 is the emitter voltage VEQ1 of the first transistor Q1, that is, VC1=VEQ1, and the voltage of the second node C2 is the sum of the emitter voltage VEQ2 of the second transistor Q2 and the voltage of the sixth resistor R6, that is, VC2=VR6+VEQ2. When the circuit is just powered on, the current I3 flowing through the first transistor Q1 and the current I4 flowing through the second transistor Q2 are both small. Therefore, at the initial stage of the circuit powering on, the voltage difference VR6 across the sixth resistor R6 is small, and the voltage VC1 of the first node C1 is greater than the voltage VC2 of the second node C2, that is, the control terminal voltage of the tenth switch tube M10 is less than the control terminal voltage of the eighth switch tube M8, and the output terminal of the tenth switch tube M10 is connected to the output terminal of the eighth switch tube M8, so it can be obtained that the voltage difference between the control terminal and the output terminal of the eighth switch tube M8 is greater than the voltage difference between the control terminal and the output terminal of the tenth switch tube M10. Since the seventh switch tube M7 and the ninth switch tube M9 form a 1:1 current mirror structure, the ninth switch tube M9 is connected in series with the tenth switch tube M10, therefore, the current flowing from the third node E to the eighth switch tube M8 is greater than the current flowing from the seventh switch tube M7 to the third node E, and the voltage of the third node E is pulled down. The third node E is connected to the control end of the fifth switch tube M5 and the sixth switch tube M6, and the voltage of the control end of the fifth switch tube M5 and the sixth switch tube M6 is reduced, and the voltage difference between the control end and the output end of the fifth switch tube M5 and the sixth switch tube M6 is increased, so the current flowing out of the fifth switch tube M5 and the sixth switch tube M6 is increased, and therefore, the current I3 flowing through the first triode Q1 and the current I4 flowing through the second triode Q2 are increased. At this time, as the current I3 and the current I4 increase, the voltage difference VR6 across the sixth resistor R6 becomes larger and larger, so that the voltage VC2 of the second node C2 gradually increases. When the voltage VC2 of the second node C2 increases to be greater than the voltage VC1 of the first node C1, the voltage of the control end of the tenth switch tube M10 is greater than the voltage of the control end of the eighth switch tube M8.At this time, the voltage difference between the control end and the output end of the tenth switch tube M10 is greater than the voltage difference between the control end and the output end of the eighth switch tube M8. Therefore, the current flowing from the third node E to the eighth switch tube M8 is less than the current flowing from the seventh switch tube M7 to the third node E. The voltage of the third node E increases, causing the voltage difference between the control end and the output end of the fifth switch tube M5 and the sixth switch tube M6 to decrease. Then, the current flowing out of the fifth switch tube M5 and the sixth switch tube M6 decreases, and the circuit enters the next cycle.

[0057] It can be seen that when the circuit is in a stable state, the voltage of the first node C1 is equal to the voltage of the second node C2, that is, ,but , where Vt represents the thermal voltage value of the first transistor Q1 and the second transistor Q2, which has a positive temperature coefficient, and IS represents the reverse saturation current of the first transistor Q1 and the second transistor Q2. At this time, since the fifth switch tube M5, the sixth switch tube M6, the first switch tube M1 and the second switch tube M2 form a 1:1:M:M current mirror structure, when the circuit is in a stable state, the current I1 flowing through the first switch tube M1 is equal to the current I2 flowing through the second switch tube M2, that is, .

[0058] In some embodiments, in the above formula for the rate at which the threshold current ID0 changes with the temperature T, the formula for the constant P is: ; in, represents the resistance value of the first resistor R1 at room temperature, Indicates the thermal voltage value of the first transistor Q1 and the second transistor Q2 at room temperature.

[0059] In some embodiments, the fourth resistor R4 , the fifth resistor R5 , and the sixth resistor R6 are all resistors of the same type inside the chip.

[0060] From the above analysis, it can be seen that the threshold current of the current detection circuit in the present invention is , and because ,but , and the fourth resistor R4, the fifth resistor R5 and the sixth resistor R6 are all resistors of the same type inside the chip, therefore, the formula The temperature coefficient of resistance in the numerator and denominator can be offset, that is, It has nothing to do with temperature and can be regarded as a constant. M and lnN are also constants. The first resistor R1 is a metal resistor with a positive temperature coefficient. At the same time, the thermal voltage value Vt of the first transistor Q1 and the second transistor Q2 also has a positive temperature coefficient. Therefore, the formula related to temperature in the threshold current ID0 is as follows: ; According to the formula, the parameters in the numerator and denominator of the threshold current ID0 both have positive temperature coefficients, and the effects of temperature on these parameters offset each other to a certain extent, thereby effectively reducing the overall temperature coefficient of the threshold current ID0.

[0061] If all temperature-independent constant parameters in the temperature-dependent formula of the threshold current ID0 are expressed as P, then At this time, the threshold current ID0 can be expressed as: , by taking the derivative of the parameter T representing the temperature in the threshold current ID0 formula, we can get the rate formula of the threshold current ID0 changing with temperature T: ; Among them, P, T0 and a are all constants, so, It is inversely proportional to the square of the temperature T, that is, as the temperature T increases, the rate at which the threshold current ID0 changes with the temperature T decreases, that is, the sensitivity of the threshold current ID0 to temperature decreases.

[0062] According to the embodiment of the present invention, by using a positive temperature coefficient resistor outside the power control chip and coordinating the design with the internal circuit of the power control chip, the threshold current of the current detection circuit has a lower temperature coefficient while realizing basic functions such as current detection, thereby effectively reducing the impact of temperature changes on detection accuracy. At the same time, the present invention adopts optimized designs such as current mirror, resistor network and multi-stage switch tube control to improve the stability and sensitivity of current detection.

[0063] The following is a specific implementation process to further explain that the threshold current ID0 of the current detection circuit of the present invention has a lower temperature coefficient.

[0064] When constant N is 4, constant M is 5, constant a is 0.0038, the resistance of resistor R6 is , the resistance difference between resistor R4 and resistor R5 is , room temperature T0 is 300K, the resistance value of the first resistor R1 at room temperature for At room temperature, the thermal voltage values ​​of the first transistor Q1 and the second transistor Q2 are When , , , , , , , At this time, if the temperature T is 300K, substituting it into the formula of the rate at which the threshold current ID0 changes with the temperature T, we can get: , and when the temperature T is 400K, substituting it into the rate formula of the threshold current ID0 changing with the temperature T, we can get: . Figure 6 FIG. 1 is a schematic diagram showing the change of the threshold current of a current detection circuit with a low temperature coefficient according to an embodiment of the present invention with respect to temperature. Figure 6 As shown, the threshold current of the low temperature coefficient current detection circuit of the present invention is always around 1.2A. Combined with the above calculation results, it can be seen that the temperature coefficient of the threshold current of the present invention is a few tenths of a tenth ... , which is much lower than that of the existing technology. , which is at least one order of magnitude lower than the temperature coefficient in the prior art.

[0065] also, Figure 7 The schematic diagram shows the change rate of the threshold current of the current detection circuit with low temperature coefficient according to one embodiment of the present invention. Figure 7 It can be seen that in the current detection circuit of the present invention, as the temperature increases, the slope of the rate of change of the threshold current with temperature decreases, that is, the threshold current change decreases. In other words, the higher the temperature, the smaller the temperature coefficient of the threshold current of the current detection circuit of the present invention.

[0066] It can be seen from this that the current detection circuit in the present invention has a relatively low temperature coefficient, and the higher the operating temperature, the lower the temperature coefficient of the threshold current.

[0067] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A current detection circuit with a low temperature coefficient, characterized in that: Used to detect the current signal of the circuit to be tested, the circuit to be tested includes a first resistor R1, the current detection circuit includes a current module, a regulating module and a comparing module, and the regulating module includes: The regulating unit has a first input terminal, a second input terminal, a first output terminal and a second output terminal, wherein the first output terminal is connected to one end of the first resistor R1, the second output terminal is grounded, and the other end of the first resistor R1 is grounded; The first switch tube M1 has an input terminal connected to the power supply voltage VDD, an output terminal connected to the first input terminal of the regulating unit and the comparison module, and a control terminal connected to the current module; The second switch tube M2 has an input terminal connected to the power supply voltage VDD, an output terminal connected to the second input terminal of the regulating unit and the comparison module, and a control terminal connected to the control terminal of the first switch tube M1; Among them, the adjustment unit is configured to adjust the voltage magnitude relationship between the output end of the first switch tube M1 and the output end of the second switch tube M2 according to the magnitude relationship between the measured current ID of the measured circuit and the threshold current ID0, thereby adjusting the level of the output voltage VO at the output end of the current detection circuit. The sensitivity of the threshold current ID0 to temperature decreases as the temperature increases.

2. The current detection circuit according to claim 1, characterized in that: The rate formula of the threshold current ID0 changing with temperature T is: ； Wherein, P is a constant, a represents the temperature coefficient of the first resistor R1, and a is greater than 0, T0 represents the room temperature, Indicates the rate at which the threshold current changes with temperature.

3. The current detection circuit according to claim 2, characterized in that: The regulating unit includes a second resistor R2 and a third resistor R3 connected in series, a third switch tube M3 and a fourth resistor R4 connected in sequence, and a fourth switch tube M4 and a fifth resistor R5 connected in sequence; The control end of the third switch tube M3 is connected to the control end of the fourth switch tube M4 and is connected between the second resistor R2 and the third resistor R3. The end of the fourth resistor R4 away from the third switch tube M3 serves as the first output end. An end of the fifth resistor R5 away from the fourth switch tube M4 serves as a second output end; One end of the second resistor R2 away from the third resistor R3 is connected to the input end of the third switch tube M3 and serves as the first input end. One end of the third resistor R3 away from the second resistor R2 is connected to the input end of the fourth switch tube M4 and serves as the second input end.

4. The current detection circuit according to claim 3, characterized in that: In the current module, the power supply voltage VDD is grounded through the fifth switch tube M5 and the first transistor Q1 in sequence; the power supply voltage VDD is also grounded through the sixth switch tube M6, the sixth resistor R6 and the second transistor Q2 in sequence; The control end of the fifth switch tube M5 is connected to the control end of the sixth switch tube M6 and is merged into the control end of the first switch tube M1. The first transistor Q1 and the second transistor Q2 are both diode-connected.

5. The current detection circuit according to claim 4, characterized in that: The power supply voltage VDD is also grounded through the seventh switch tube M7, the eighth switch tube M8 and the first current source B1 in sequence; the power supply voltage VDD is also grounded through the ninth switch tube M9, the tenth switch tube M10 and the first current source B1 in sequence; The seventh switch tube M7 is connected to the control end of the ninth switch tube M9 and is incorporated into the output end of the ninth switch tube M9. The control end of the eighth switch tube M8 is connected to the first node C1 between the fifth switch tube M5 and the first transistor Q1. The control end of the tenth switch tube M10 is connected to the second node C2 between the sixth switch tube M6 and the sixth resistor R6. The third node E between the seventh switch tube M7 and the eighth switch tube M8 is connected to the control end of the fifth switch tube M5.

6. The current detection circuit according to claim 5, characterized in that: The fifth switch tube M5, the sixth switch tube M6, the first switch tube M1 and the second switch tube M2 form a 1:1:M:M current mirror structure; The number ratio of the first transistor Q1 to the second transistor Q2 is 1:N; The seventh switch tube M7 and the ninth switch tube M9 form a 1:1 current mirror structure.

7. The current detection circuit according to claim 6, characterized in that: In the formula for the rate at which the threshold current ID0 changes with temperature T, the formula for the constant P is: ； in, represents the resistance value of the first resistor R1 at room temperature, Indicates the thermal voltage value of the first transistor Q1 and the second transistor Q2 at room temperature.

8. The current detection circuit according to any one of claims 4 to 7, characterized in that: The comparison module includes a comparison unit and an output unit; In the comparison unit, the power supply voltage VDD is connected to the ground through the second current source B2, the eleventh switch tube M11 and the seventh resistor R7 in sequence, and the power supply voltage VDD is also connected to the ground through the second current source B2, the twelfth switch tube M12 and the eighth resistor R8 in sequence; the control end of the eleventh switch tube M11 is connected to the output end of the second switch tube M2; the control end of the twelfth switch tube M12 is connected to the output end of the first switch tube M1; The fourth node F1 between the eleventh switch tube M11 and the seventh resistor R7 and the fifth node F2 between the twelfth switch tube M12 and the eighth resistor R8 are both connected to the output unit; the output unit is configured to adjust the level of the output voltage VO in the output unit according to the size relationship between the fourth node F1 and the fifth node F2.

9. The current detection circuit according to claim 8, characterized in that: In the output unit, the power supply voltage VDD is grounded through the third current source B3, the thirteenth switch tube M13 and the fourteenth switch tube M14 in sequence; the power supply voltage VDD is also grounded through the third current source B3, the fifteenth switch tube M15 and the sixteenth switch tube M16 in sequence; the control end of the thirteenth switch tube M13 is connected to the fourth node F1, and the control end of the fifteenth switch tube M15 is connected to the fifth node F2; the control end of the fourteenth switch tube M14 is connected to the input end of the fourteenth switch tube M14, and the control end of the sixteenth switch tube M16 is connected to the input end of the sixteenth switch tube M16; The power supply voltage VDD is also grounded through the seventeenth switch tube M17 and the eighteenth switch tube M18 in sequence; the power supply voltage VDD is also grounded through the nineteenth switch tube M19 and the twentieth switch tube M20 in sequence; the control end of the seventeenth switch tube M17 is connected to the control end of the nineteenth switch tube M19 and is merged into the output end of the seventeenth switch tube M17; the control end of the eighteenth switch tube M18 is connected to the control end of the fourteenth switch tube M14, and the control end of the twentieth switch tube M20 is connected to the control end of the sixteenth switch tube M16; The output end of the current detection circuit is located between the nineteenth switch tube M19 and the twentieth switch tube M20.

10. The current detection circuit according to claim 9, characterized in that: The fourteenth switch tube M14 and the eighteenth switch tube M18 form a 1:1 current mirror structure; The sixteenth switch tube M16 and the twentieth switch tube M20 form a 1:1 current mirror structure; The seventeenth switch tube M17 and the nineteenth switch tube M19 form a 1:1 current mirror structure.

11. The current detection circuit according to any one of claims 9 to 10, characterized in that: When the measured current ID is less than the threshold current ID0, the output voltage VO is a first level signal; When the measured current ID is greater than the threshold current ID0, the output voltage VO is a second level signal; A first level corresponding to the first level signal is lower than a second level corresponding to the second level signal.

12. A power supply circuit, characterized in that: comprising a circuit to be tested, a logic circuit and a current detection circuit as claimed in any one of claims 1 to 11; In the circuit to be tested, the input power source VIN is grounded through the first power switch tube Mp1, the second power switch tube Mp2 and the first resistor R1 in sequence; the control end of the first power switch tube Mp1 and the control end of the second power switch tube Mp2 are both connected to the logic circuit; The circuit to be tested further includes a first inductor L1 and a first capacitor C1, one end of the first inductor L1 is connected between the first power switch tube Mp1 and the second power switch tube Mp2, and the other end is connected to the output end VOUT of the power supply circuit; one end of the first capacitor C1 is connected to the output end VOUT of the power supply circuit, and the other end is grounded; The current detection circuit is connected to the logic circuit and is used to output a voltage signal to the logic circuit; The current detection circuit is connected to a sixth node A between the first resistor R1 and the second power switch tube Mp2, and the current detection circuit is grounded.

13. The power supply circuit according to claim 12, characterized in that: When the first power switch tube Mp1 is turned on and the second power switch tube Mp2 is turned off, the output voltage VO is a first level signal.

14. The power supply circuit according to claim 12 or 13, characterized in that: When the first power switch tube Mp1 is turned off and the second power switch tube Mp2 is turned on, the voltage relationship between the output end of the first switch tube M1 and the output end of the second switch tube M2 is adjusted according to the relationship between the measured current ID of the measured circuit and the threshold current ID0, thereby adjusting the level of the output voltage VO of the current detection circuit.

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