Resistance calibration circuit, resistance calibration equipment and electronic equipment

Abstract

The embodiment of the utility model provides a resistor calibration circuit, a resistor calibration device and an electronic device. The resistor calibration circuit comprises a current source module used for outputting a reference current; the standard resistor module is connected with the current source module to receive the reference current and generate a reference voltage; in the working process of the resistor calibration circuit, a resistor to be calibrated is connected with the current source module to receive the reference current and generate a voltage to be measured, and the analog-to-digital converter is connected with the standard resistor module to perform analog-to-digital conversion on the voltage to be measured based on the reference voltage. According to the resistance calibration circuit, the analog-to-digital converter in the module to be measured is multiplexed for resistance calibration, an additional high-precision measurement calibration system is not needed, and the resistance can be calibrated only by providing the current source module and the standard resistance module, so that the resistance calibration cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of electronic device calibration, and in particular to a resistance calibration circuit, a resistance calibration device and an electronic device. Background Art

[0002] At present, electronic products need to calibrate important electronic components before leaving the factory to avoid errors in the system itself and improve the accuracy and reliability of data. Taking the measurement of load current as an example, the load current is usually passed through a current sampling resistor, and then the voltage across the current sampling resistor is measured by an analog-to-digital converter. The load current can be obtained according to the current calculation formula I=V / R. Obviously, the premise for obtaining the load current size is that the resistance value of the current sampling resistor is known. Therefore, electronic products need to calibrate the current sampling resistor before leaving the factory to reduce the measurement error of the load current.

[0003] However, in order to reduce power consumption and heat generation of electronic equipment, the resistance value of the current sampling resistor is usually in the milliohm range, so a high-precision measurement and calibration system is required to calibrate the current sampling resistor, which leads to the technical problem of high cost of resistor calibration. Utility Model Content

[0004] In view of the above problems, the embodiments of the present application provide a resistance calibration circuit, a resistance calibration device and an electronic device to solve the above technical problems.

[0005] In a first aspect, an embodiment of the present application provides a resistance calibration circuit, which is used to calibrate the resistance of a module to be measured, wherein the module to be measured includes at least one resistor to be calibrated and an analog-to-digital converter for performing analog-to-digital conversion on the voltage across the resistor to be calibrated, and the resistance calibration circuit includes:

[0006] A current source module for outputting a reference current;

[0007] A standard resistance module, the standard resistance module is connected to the current source module to receive a reference current and generate a reference voltage;

[0008] Among them, during the operation of the resistance calibration circuit, the resistance to be calibrated is connected to the current source module to receive the reference current and generate the voltage to be measured, and the analog-to-digital converter is connected to the standard resistance module to perform analog-to-digital conversion on the voltage to be measured based on the reference voltage.

[0009] In a second aspect, the present application provides a resistance calibration device, comprising the resistance calibration circuit as described in the first aspect.

[0010] In a third aspect, the present application provides an electronic device, including:

[0011] At least one resistor to be calibrated;

[0012] An analog-to-digital converter, the analog-to-digital converter is connected to the resistor to be calibrated to perform analog-to-digital conversion on the voltage across the resistor to be calibrated;

[0013] As described in the first aspect, the resistance calibration circuit is used to calibrate the resistance to be calibrated.

[0014] The present application outputs a reference current through a current source module, and generates a reference voltage using a standard resistance module that flows through the reference current. During the operation of the resistance calibration circuit, the resistance to be calibrated is connected to the current source module to receive the reference current and generate a voltage to be measured. Since the analog-to-digital converter performs analog-to-digital conversion on the voltage to be measured based on the reference voltage, the ratio of the full swing code value of the analog-to-digital converter to the conversion code value of the voltage to be measured relative to the ratio of the standard resistance module to the resistance to be calibrated satisfies a preset relationship (e.g., equal), that is, the full swing code value of the analog-to-digital converter and the standard resistance are known quantities, and the conversion code value of the voltage to be measured is a measured value, so the resistance value of the resistance to be calibrated can be determined in the end. In other words, the resistance calibration circuit of the present application reuses the analog-to-digital converter in the module to be measured for resistance calibration, and no additional high-precision measurement calibration system is required. Only a current source module and a standard resistance module with a known resistance value are required to calibrate the resistance, which is conducive to reducing the cost of resistance calibration.

[0015] These and other aspects of the present application will become more clearly understood in the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A schematic diagram of measuring load current by an electronic device in the related art is shown.

[0018] Figure 2 A module schematic diagram of a resistance calibration circuit and a module to be measured in an embodiment of the present application is shown.

[0019] Figure 3 Another module schematic diagram of the resistance calibration circuit and the module to be measured in the embodiment of the present application is shown.

[0020] Figure 4 A circuit diagram of a resistance calibration circuit and a module to be measured in an embodiment of the present application is shown.

[0021] Figure 5Another circuit schematic diagram of the resistance calibration circuit and the module to be measured in the embodiment of the present application is shown.

[0022] Figure 6 Another circuit schematic diagram of the resistance calibration circuit and the module to be measured in the embodiment of the present application is shown.

[0023] Figure 7 Another circuit schematic diagram of the resistance calibration circuit and the module to be measured in the embodiment of the present application is shown.

[0024] Figure 8 Another circuit schematic diagram of the resistance calibration circuit and the module to be measured in the embodiment of the present application is shown.

[0025] Fig. 9 Another circuit schematic diagram of the resistance calibration circuit and the module to be measured in the embodiment of the present application is shown.

[0026] Fig.10 Another circuit schematic diagram of the resistance calibration circuit and the module to be measured in the embodiment of the present application is shown.

[0027] Fig.11 A schematic diagram of a resistance calibration device in an embodiment of the present application is shown.

[0028] Fig.12 A circuit diagram of an electronic device in an embodiment of the present application is shown.

[0029] Among them, 1 is a module to be measured, 100 is a resistance calibration circuit, 10 is a current source module, 20 is a standard resistance module, and 30 is a switch switching module;

[0030] Fixed current source IS, standard resistor R0, reference current I0, reference voltage Vref, analog-to-digital converter ADC, power supply terminal VDD, ground terminal GND, first PMOS tube MP1, second PMOS tube MP2, first switch S1, second switch S2, third switch S3, fourth switch S4. DETAILED DESCRIPTION

[0031] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0032] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0033] In the embodiments of the present application, it should be noted that, in this article, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0034] Moreover, the terms "comprises," "comprising," or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0035] In the description of the embodiments of the present application, words such as "example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "example" or "for example" in the embodiments of the present application is not to be interpreted as being more preferred or having more advantages than another embodiment or design. The use of words such as "example" or "for example" is intended to present relative concepts in a clear manner.

[0036] In addition, the "plurality" in the embodiments of the present application refers to two or more than two. In view of this, in the embodiments of the present application, "plurality" can also be understood as "at least two". "At least one" can be understood as one or more, for example, one, two or more. For example, including at least one means including one, two or more, and there is no limit on which ones are included. For example, including at least one of A, B and C, then A, B, C, A and B, A and C, B and C, or A, B and C can be included.

[0037] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0038] The first pole / first end of each transistor used in the embodiments of the present application is one of the source and the drain, and the second pole / second end of each transistor is the other of the source and the drain. Since the source and drain of the transistor can be symmetrical in structure, the source and drain thereof can be structurally indistinguishable, that is, the first pole / first end and the second pole / second end of the transistor in the embodiments of the present application can be structurally indistinguishable. Exemplarily, in the case where the transistor is a P-type transistor, the first pole / first end of the transistor is the source, and the second pole / second end is the drain; exemplarily, in the case where the transistor is an N-type transistor, the first pole / first end of the transistor is the drain, and the second pole / second end is the source.

[0039] Currently, electronic products need to calibrate important electronic components before leaving the factory to avoid errors in the system itself and improve the accuracy and reliability of data. Figure 1 , Figure 1 A schematic diagram of an electronic device measuring a load current in the related art is shown, the electronic device includes a battery, load 1, load 2, load 3 and a measuring chip with an analog-to-digital converter ADC, a current sampling resistor R01 is connected in series between load 1 and the battery, a current sampling resistor R02 is connected in series between load 2 and the battery, and a current sampling resistor R03 is connected in series between load 3 and the battery.

[0040] When measuring the load current, the analog-to-digital converter ADC measures the voltages V01, V02, and V03 across the current sampling resistors R01, R02, and R03, respectively, and then calculates the load currents corresponding to load 1, load 2, and load 3 according to the current calculation formula I=V / R, so as to judge whether the load current of the corresponding load is too large. Obviously, the premise for obtaining the load current is that the resistance values ​​of the current sampling resistors R01, R02, and R03 are known, so the electronic products need to calibrate the current sampling resistors before leaving the factory to reduce the measurement error of the load current. However, in order to reduce power consumption and the heat generation of electronic equipment, the resistance value of the current sampling resistor is usually in the milliohm range, so a high-precision measurement and calibration system is required to calibrate the current sampling resistor, which leads to the technical problem that the current resistor calibration procedure is cumbersome and costly.

[0041] To this end, the present application provides a resistance calibration circuit, a resistance calibration device and an electronic device, which are described in detail below.

[0042] First, see Figure 2 , Figure 2A module schematic diagram of a resistance calibration circuit 100 and a module to be measured 1 in an embodiment of the present application is shown, wherein the resistance calibration circuit 100 is used to perform resistance calibration on the module to be measured 1, wherein the module to be measured 1 includes at least one resistor R1 to be calibrated and an analog-to-digital converter ADC for performing analog-to-digital conversion of a voltage V1 across the resistor to be calibrated, wherein the resistance calibration circuit 100 includes a current source module 10 and a standard resistance module 20.

[0043] Specifically, the current source module 10 can output a reference current I0, so that after the reference current I0 flows through the standard resistance module 20, the standard resistance module 20 outputs a reference voltage Vref, and after the reference current I0 flows through the resistance to be calibrated, a voltage to be measured is generated at both ends of the resistance to be calibrated. In some embodiments of the present application, the reference current I0 does not change with the resistance value of the resistance to be calibrated or the standard resistance module 20, so as to calibrate the resistance to be calibrated with different resistance values. In some other embodiments of the present application, when the standard resistance module 20 is connected in series with the resistance to be calibrated, the size of the reference current I0 can also change with the resistance value of the resistance to be calibrated or the standard resistance module 20. At this time, the current size flowing through the standard resistance module 20 and the resistance to be calibrated is always the same, so the reference current I0 with a change in size will not affect the calibration of the resistance to be calibrated.

[0044] Exemplarily, the current source module 10 may include but is not limited to a constant current source circuit using an operational amplifier, a constant current source circuit using a parallel regulator, a constant current source circuit using a transistor (eg, a triode or a JFET), and the like.

[0045] The standard resistor module 20 is connected to the current source module 10 to receive the reference current I0 and generate a reference voltage Vref. Generally, the standard resistor module 20 includes at least one resistor with a known resistance value. After the reference current I0 flows through the standard resistor module 20, a reference voltage Vref can be generated at both ends of the resistor. Figure 2 , the standard resistance module 20 can be connected in series with the resistance to be calibrated so that the current flowing through the standard resistance module 20 and the resistance to be calibrated are the same. Figure 3 , Figure 3 Another module schematic diagram of the resistance calibration circuit 100 and the module to be measured 1 in an embodiment of the present application is shown, the standard resistance module 20 and the resistance to be calibrated are respectively connected to the current source module 10, and the reference current I0' and the reference current I0" are respectively input to the standard resistance module 20 and the resistance to be calibrated through the current source module 10.

[0046] In some embodiments of the present application, for example, in an embodiment where the standard resistance module 20 can be connected in series with the resistance to be calibrated, the reference current I0 flowing through the standard resistance module 20 and the reference current I0 flowing through the resistance to be calibrated are the same. In other embodiments of the present application, for example, in an embodiment where the standard resistance module 20 and the resistance to be calibrated are respectively connected to the current source module 10, see Figure 3 The reference current I0" flowing through the standard resistor module 20 and the reference current I0' flowing through the resistor to be calibrated satisfy a preset relationship. For example, the reference current I0" flowing through the standard resistor module 20 is twice the reference current I0' flowing through the resistor to be calibrated.

[0047] Exemplarily, the standard resistor module 20 may include, but is not limited to, a carbon film resistor, a metal film resistor, a wirewound resistor, a non-inductive resistor, a thin film resistor, a chip resistor, and the like.

[0048] In the embodiment of the present application, the present application outputs a reference current I0 through a current source module 10, and generates a reference voltage Vref by using a standard resistor module 20 through which the reference current I0 flows. During the operation of the resistor calibration circuit 100, the resistor to be calibrated is connected to the current source module 10 to receive the reference current I0 and generate a voltage to be measured. Since the analog-to-digital converter ADC performs analog-to-digital conversion on the voltage to be measured based on the reference voltage Vref, the ratio of the full swing code value of the analog-to-digital converter ADC to the conversion code value of the voltage to be measured is fully proportional to the ratio of the standard resistor module 20 to the resistor to be calibrated. When the preset relationship is satisfied (for example, they are equal), the full-swing code value of the analog-to-digital converter ADC and the standard resistance R0 are known quantities, and the conversion code value of the voltage to be measured is the measured value, the resistance value of the resistance to be calibrated can be determined after the conversion code value of the voltage to be measured is obtained. That is to say, the resistance calibration circuit 100 of the present application reuses the analog-to-digital converter ADC in the module to be measured 1 for resistance calibration, and does not require an additional high-precision measurement and calibration system. Only the current source module 10 and the standard resistance module 20 need to be provided to calibrate the resistance, which is beneficial to reduce the cost of resistance calibration.

[0049] It should be noted that the analog-to-digital converter ADC performs analog-to-digital conversion on the voltage to be measured based on the reference voltage Vref, which actually uses the reference voltage Vref as a standard to measure the voltage to be measured. Therefore, the conversion code value of the voltage to be measured measured by the analog-to-digital converter ADC is actually equivalent to the ratio of the voltage to be measured to the reference voltage Vref. As an example, taking the analog-to-digital converter ADC as a successive approximation analog-to-digital converter as an example, if the measurement conversion code value of the voltage to be measured V1 is 0111 (corresponding to decimal code 7), the reference voltage Vref is 8V, and the full swing code value of the successive approximation analog-to-digital converter ADC corresponding to the reference voltage Vref is 1111 (corresponding to decimal code 15), then the ratio of the reference voltage Vref to the analog input voltage VIN satisfies:

[0050]

[0051] That is, the ratio of the measured voltage V1 to the reference voltage Vref can be obtained by the ratio of the measured conversion code value converted by the measured voltage V1 to the full swing code value, and the resistance value of the resistor to be calibrated can be determined.

[0052] For example, taking the reference current I0 flowing through the standard resistor module 20 and the reference current I0 flowing through the resistor to be calibrated as being the same, it can be known that the first ratio between the resistor to be calibrated and the standard resistor R0 is equal to the second ratio between the measured conversion code value and the full-scale conversion code value, that is:

[0053]

[0054] Among them, R1 is the resistance to be calibrated, V1 is the voltage to be measured, D1 is the code value obtained after the analog-to-digital converter ADC performs analog-to-digital conversion on the voltage to be measured V1, and Dmax is the full-swing code value of the analog-to-digital converter ADC corresponding to the reference voltage Vref.

[0055] It can be further known that the resistance value of the resistor to be calibrated can be calculated according to the following formula:

[0056]

[0057] It can be seen that in the above formula, R0 and Dmax are known quantities, and D1 is a measured value, so the resistance value of the resistor to be calibrated can be determined in the end. At the same time, the above formula is not related to the magnitude of the reference current I0, and the magnitude of the reference current I0 remains unchanged or changes with the magnitude of the reference current I0 as the resistor to be calibrated. This will not affect the measurement of the resistor to be calibrated in this application.

[0058] It can be understood that when the reference current I0 flowing through the standard resistor module 20 and the reference current I0 flowing through the resistor to be calibrated meet a preset relationship, for example, the reference current I0 flowing through the standard resistor module 20 is twice the reference current I0 flowing through the resistor to be calibrated, the resistance value calculation formula of the resistor to be calibrated can be adaptively modified to:

[0059]

[0060] In some embodiments of the present application, for example, the standard resistance module 20 can be connected in series with the resistance to be calibrated, see Figure 4 , Figure 4 A circuit diagram of a resistance calibration circuit 100 and a module to be measured 1 in an embodiment of the present application is shown, wherein the current source module 10 includes a fixed current source IS, and the standard resistance module 20 includes a standard resistor R0; the input end of the fixed current source IS is connected to the power supply end VDD, and the output end of the fixed current source IS is connected to the first end of the standard resistor R0; during the operation of the resistance calibration circuit 100, the second end of the standard resistor R0 is connected to the resistance to be calibrated to input a reference current I0 to the resistance to be calibrated, and the first end of the standard resistor R0 and the second end of the standard resistor R0 are connected to the analog-to-digital converter ADC to input a reference voltage Vref to the analog-to-digital converter ADC. In other words, the resistance to be calibrated and the standard resistor R0 are connected in series, so that the current flowing through the resistance to be calibrated and the standard resistor R0 is equal in magnitude, and after the analog-to-digital converter ADC performs analog-to-digital conversion on the voltage to be measured based on the reference voltage Vref, the resistance value of the resistance to be calibrated can be calculated.

[0061] In some embodiments of the present application, for example, in an embodiment where the standard resistance module 20 and the resistance to be calibrated are respectively connected to the current source module 10, see Figure 5 , Figure 5 Another circuit schematic diagram of the resistance calibration circuit 100 and the module to be measured 1 in an embodiment of the present application is shown, the current source module 10 includes a fixed current source IS and a first current mirror, and the standard resistance module 20 includes a standard resistor R0; the fixed current source IS is connected to the first mirror branch of the first current mirror, and the standard resistor R0 is connected to the second mirror branch of the first current mirror; during the operation of the resistance calibration circuit 100, the fixed current source IS is connected to the resistor to be calibrated to input a reference current I0 to the resistor to be calibrated, and the first end of the standard resistor R0 and the second end of the standard resistor R0 are connected to the analog-to-digital converter ADC to input a reference voltage Vref to the analog-to-digital converter ADC.

[0062] It should be noted that the first current mirror can mirror the current flowing through the first mirror branch and the current flowing through the second mirror branch. For example, the first current mirror can make the current flowing through the first mirror branch equal to the current flowing through the second mirror branch, so that the current flowing through the resistor to be calibrated and the standard resistor R0 are the same; for another example, the first current mirror can make the current flowing through the second mirror branch twice the current flowing through the first mirror branch, so that the reference current I0 flowing through the standard resistor module 20 is twice the reference current I0 flowing through the resistor to be calibrated. After the analog-to-digital converter ADC performs analog-to-digital conversion on the measured voltage based on the reference voltage Vref, the resistance value of the resistor to be calibrated can be calculated based on the relationship between the current flowing through the second mirror branch and the current flowing through the first mirror branch.

[0063] As an example, see Figure 6 , Figure 6 Another circuit schematic diagram of the resistance calibration circuit 100 and the module to be measured 1 in the embodiment of the present application is shown, and the first current mirror includes a first PMOS tube MP1 and a second PMOS tube MP2; the first end of the first PMOS tube MP1 is connected to the power supply terminal VDD, the second end of the first PMOS tube MP1 is connected to the fixed current source IS, and the control end of the first PMOS tube MP1 is connected to the second end of the first PMOS tube MP1; the first end of the second PMOS tube MP2 is connected to the power supply terminal VDD, the second end of the second PMOS tube MP2 is connected to the standard resistor R0, and the control end of the second PMOS tube MP2 is connected to the control end of the second PMOS tube MP2.

[0064] Specifically, during the operation of the resistance calibration circuit 100, the fixed current source IS outputs a reference current I0 of a fixed magnitude, and makes the current flowing through the first PMOS tube MP1 equal to the reference current I0, and the first PMOS tube MP1 generates a fixed voltage drop. Since the control end of the second PMOS tube MP2 is connected to the control end of the second PMOS tube MP2, the first end and the control end voltage of the first PMOS tube MP1 and the second PMOS tube MP2 are the same. When the first PMOS tube MP1 and the second PMOS tube MP2 have the same size, the second PMOS tube MP2 can output a reference current I0 of equal magnitude. At the same time, when the ratio of the number of the first PMOS tube MP1 to the second PMOS tube MP2 is changed, the ratio of the current flowing through the first mirror branch to the current flowing through the second mirror branch can be changed. For example, when the ratio of the number of the first PMOS tube MP1 to the second PMOS tube MP2 is 1:1, the current flowing through the first mirror branch is equal to the current flowing through the second mirror branch; for another example, when the ratio of the number of the first PMOS tube MP1 to the second PMOS tube MP2 is 1:2, the current flowing through the second mirror branch is twice the current flowing through the first mirror branch.

[0065] It can be understood that the above embodiment is an exemplary description of the current mirror composed of PMOS tubes, but is not limited to this. For example, a current mirror composed of NMOS tubes can also be used to provide reference currents of the same or different sizes to the standard resistor R0 and the resistor to be calibrated R1 respectively.

[0066] In some embodiments of the present application, see Figure 7 , Figure 7 Another circuit diagram of the resistance calibration circuit 100 and the module to be measured 1 in the embodiment of the present application is shown, the module to be measured 1 includes a plurality of resistors to be calibrated R1 to R3, the resistance calibration circuit 100 also includes a switch switching module 30, the switch switching module 30 is connected to the plurality of resistors to be calibrated, and can control a resistor to be calibrated to receive a reference current I0. That is to say, when it is necessary to calibrate a plurality of resistors to be calibrated R1 to R3, the switch switching module 30 controls different resistors to be calibrated to receive the reference current I0, and then measures the voltage to be measured V1 to V3 output by the corresponding resistor to be calibrated through the analog-to-digital converter ADC, so that the resistance value calibration of different resistors to be calibrated can be realized, which is ultimately conducive to reducing the cumbersomeness of the resistance value calibration process of the plurality of resistors to be calibrated R1 to R3.

[0067] As an example, see Figure 8 , Figure 8 Another circuit schematic diagram of the resistance calibration circuit 100 and the module to be measured 1 in the embodiment of the present application is shown, the switch switching module 30 includes a plurality of first switches S1, and the first switches S1 correspond one to one to the resistance to be calibrated; during the operation of the resistance calibration circuit 100, the first end of the first switch S1 is connected to the second end of the corresponding resistance to be calibrated, and the second end of the first switch S1 is connected to the ground terminal GND. When the first switch S1 is closed, the conduction between the resistance to be calibrated and the ground terminal GND is turned on, so the reference current I0 can flow through the resistance to be calibrated and generate the corresponding voltage to be measured, so that the analog-to-digital converter ADC performs analog-to-digital conversion on the voltage to be measured.

[0068] As another example, see Fig. 9 , Fig. 9Another circuit schematic diagram of the resistance calibration circuit 100 and the module to be measured 1 in the embodiment of the present application is shown, the switch switching module 30 includes a plurality of second switches S2, and the second switches S2 correspond one to one to the resistance to be calibrated; during the operation of the resistance calibration circuit 100, the first end of each second switch S2 is connected to the current source module 10, and the second end of the second switch S2 is connected to the first end of the corresponding resistance to be calibrated. When a second switch S2 is closed, the conduction between the resistance to be calibrated and the current source module 10 is turned on, so that the reference current I0 can flow through the resistance to be calibrated and generate a corresponding voltage to be measured, so that the analog-to-digital converter ADC performs analog-to-digital conversion on the voltage to be measured.

[0069] In some embodiments of the present application, see Fig.10 , Fig.10 Another circuit schematic diagram of the resistance calibration circuit 100 and the module to be measured 1 in an embodiment of the present application is shown, and the resistance calibration circuit 100 also includes a third switch S3 and a fourth switch S4; the first end of the third switch S3 is connected to the standard resistance module 20, and the second end of the third switch S3 is connected to the ground terminal GND; the first end of the fourth switch S4 is connected to the standard resistance module 20, and the second end of the fourth switch S4 is connected to the resistance to be calibrated.

[0070] It should be noted that when the third switch S3 is closed and the fourth switch S4 is opened, the reference current I0 output by the current source module 10 flows entirely through the standard resistance module 20. When the reference current I0 is known, an analog-to-digital converter ADC (for example, the analog-to-digital converter ADC of the module 1 to be measured) can be used to measure the reference voltage Vref output by the standard resistance module 20 so as to determine the resistance value of the standard resistance module 20. After determining the resistance value of the standard resistance module 20, the third switch S3 is opened and the fourth switch S4 is closed, so that the reference current I0 output by the current source module 10 flows normally through the resistance to be calibrated and the resistance value is calibrated.

[0071] In some embodiments of the present application, see Fig.10 The resistance calibration circuit 100 may further include a voltage buffer 40. The reference voltage Vref outputted from both ends of the standard resistor R0 is inputted to the analog-to-digital converter ADC through the voltage buffer 40, so as to output a stable and more accurate reference voltage Vref through the voltage buffer 40, thereby helping to avoid the phenomenon that the measurement accuracy of the analog-to-digital converter ADC is reduced due to voltage fluctuation problems.

[0072] It is worth noting that the above content about the resistance calibration circuit 100 is intended to clearly illustrate the implementation verification process of the present application. Those skilled in the art can also make equivalent modified designs under the guidance of the present application. For example, a current mirror is used to replicate and output multiple reference currents I0, so as to simultaneously input the reference current I0 to multiple resistors to be calibrated and generate corresponding voltages to be measured; for example, the standard resistor module 20 can use multiple standard resistors R0 connected in series to output the reference voltage Vref.

[0073] In order to better implement the resistance calibration circuit 100 in the embodiment of the present application, based on the resistance calibration circuit 100, the present application also provides a resistance calibration device, see Fig.11 , Fig.11 A schematic diagram of a resistance calibration device in an embodiment of the present application is shown, and the resistance calibration device includes the resistance calibration circuit 100 described in any of the above embodiments. When performing resistance calibration, the reference current I0 output interface of the resistance calibration device is connected to the interface of the resistance to be calibrated of the module to be measured 1, and the reference voltage Vref output interface of the resistance calibration device is connected to the interface of the analog-to-digital converter ADC of the module to be measured 1, so that the resistance calibration circuit 100 outputs the reference current I0 to the resistance to be calibrated through the reference current I0 output interface, and outputs the reference voltage Vref to the analog-to-digital converter ADC through the reference voltage Vref output interface. After obtaining the conversion code value outputted at the analog-to-digital converter ADC of the module to be measured 1, the resistance value of the resistance to be calibrated can be determined.

[0074] It can be seen that the resistance calibration device of the present application reuses the analog-to-digital converter ADC of the module 1 to be measured, and does not require an additional high-precision measurement and calibration system. It only needs to provide a resistance calibration circuit 100 including a current source module 10 and a standard resistance module 20 to calibrate the resistance, which is beneficial to reduce the cost of resistance calibration.

[0075] Exemplarily, the module to be measured 1 may be, but is not limited to, a weight scale, a body fat scale, a nutrition scale, an infrared electronic thermometer, a pulse oximeter, a human body composition analyzer, a mobile power supply, a wireless charger, a fast charger, a car charger, an adapter, a display, a USB (Universal Serial Bus) docking station, a stylus, a true wireless headset, a car central control panel, a car, a smart wearable device, a mobile terminal, and a smart home device. Smart wearable devices include, but are not limited to, smart watches, smart bracelets, and cervical massagers. Mobile terminals include, but are not limited to, smart phones, laptops, tablet computers, and POS (point of sales terminal). Smart home devices include, but are not limited to, smart sockets, smart rice cookers, smart sweepers, and smart lights.

[0076] The present application also provides an electronic device, which includes a resistor to be calibrated, an analog-to-digital converter, and the resistance calibration circuit 100 described in any of the above embodiments. That is, the present application can also directly set the resistance calibration circuit 100 in the electronic device to directly perform resistance calibration. For example, see Fig.12 , Fig.12 A circuit diagram of an electronic device in an embodiment of the present application is shown, and the electronic device includes a battery, loads 1 to 3, resistors to be calibrated R1 to R3, a measuring chip including an analog-to-digital converter ADC, and a resistance calibration circuit 100. When performing resistance calibration, loads 1 to 3 are disconnected from the battery, and a first switch S1 is closed, so that the resistance value of the corresponding resistor to be calibrated can be calibrated.

[0077] Exemplarily, the electronic device may be, but is not limited to, a weight scale, a body fat scale, a nutrition scale, an infrared electronic thermometer, a pulse oximeter, a human body composition analyzer, a mobile power supply, a wireless charger, a fast charger, a car charger, an adapter, a display, a USB (Universal Serial Bus) docking station, a stylus, a true wireless headset, a car central control panel, a car, a smart wearable device, a mobile terminal, and a smart home device. Smart wearable devices include, but are not limited to, smart watches, smart bracelets, and cervical massagers. Mobile terminals include, but are not limited to, smart phones, laptops, tablet computers, and POS (point of sales terminal). Smart home devices include, but are not limited to, smart sockets, smart rice cookers, smart sweepers, and smart lights.

[0078] The above are only preferred embodiments of the present application, and are not intended to limit the present application in any form. Although the present application has been disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technical personnel in the field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present application. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A resistance calibration circuit, characterized in that: The resistance calibration circuit is used to perform resistance calibration on a module to be measured, wherein the module to be measured includes at least one resistor to be calibrated and an analog-to-digital converter for performing analog-to-digital conversion on the voltage across the resistor to be calibrated. The resistance calibration circuit includes: A current source module for outputting a reference current; A standard resistance module, the standard resistance module is connected to the current source module to receive the reference current and generate a reference voltage; Among them, during the operation of the resistance calibration circuit, the resistance to be calibrated is connected to the current source module to receive the reference current and generate the voltage to be measured, and the analog-to-digital converter is connected to the standard resistance module to perform analog-to-digital conversion on the voltage to be measured based on the reference voltage.

2. The resistance calibration circuit according to claim 1, characterized in that: A first ratio between the resistance to be calibrated and the standard resistance is equal to a second ratio between the measured conversion code value and the full-scale conversion code value; The measurement conversion code value is a code value obtained after the analog-to-digital converter performs analog-to-digital conversion on the voltage to be measured, and the full-scale conversion code value is a full-swing code value of the analog-to-digital converter corresponding to the reference voltage.

3. The resistance calibration circuit according to claim 1, characterized in that: The current source module includes a fixed current source, and the standard resistance module includes a standard resistance; The input end of the fixed current source is connected to the power supply end, and the output end of the fixed current source is connected to the first end of the standard resistor; During the operation of the resistance calibration circuit, the second end of the standard resistor is connected to the resistor to be calibrated to input the reference current to the resistor to be calibrated, and the first end of the standard resistor and the second end of the standard resistor are connected to the analog-to-digital converter to input the reference voltage to the analog-to-digital converter.

4. The resistance calibration circuit according to claim 1, characterized in that: The current source module includes a fixed current source and a first current mirror, and the standard resistance module includes a standard resistance; The fixed current source is connected to a first mirror branch of the first current mirror, and the standard resistor is connected to a second mirror branch of the first current mirror; During the operation of the resistance calibration circuit, the fixed current source is connected to the resistor to be calibrated to input the reference current into the resistor to be calibrated, and the first end of the standard resistor and the second end of the standard resistor are connected to the analog-to-digital converter to input the reference voltage into the analog-to-digital converter.

5. The resistance calibration circuit according to claim 1, characterized in that: The module to be measured includes a plurality of resistors to be calibrated, and the resistance calibration circuit also includes a switch switching module; The switch switching module is connected to a plurality of the resistors to be calibrated to control one of the resistors to be calibrated to receive the reference current.

6. The resistance calibration circuit according to claim 5, characterized in that: The switch switching module includes a plurality of first switches, and the first switches correspond to the resistances to be calibrated one by one; During the operation of the resistance calibration circuit, the first end of the first switch is connected to the second end corresponding to the resistance to be calibrated, and the second end of the first switch is connected to the ground end.

7. The resistance calibration circuit according to claim 5, characterized in that: The switch switching module includes a plurality of second switches, and the second switches correspond one to one to the resistance to be calibrated; During the operation of the resistance calibration circuit, the first end of each second switch is connected to the current source module, and the second end of the second switch is connected to the first end of the corresponding resistor to be calibrated.

8. The resistance calibration circuit according to claim 1, characterized in that: The resistance calibration circuit also includes a third switch and a fourth switch; A first end of the third switch is connected to the standard resistance module, and a second end of the third switch is connected to the ground end; A first end of the fourth switch is connected to the standard resistance module, and a second end of the fourth switch is connected to the resistance to be calibrated.

9. A resistance calibration device, characterized in that: The invention comprises a resistance calibration circuit as claimed in any one of claims 1 to 8.

10. An electronic device, characterized in that: include: at least one resistor to be calibrated; An analog-to-digital converter, the analog-to-digital converter is connected to the resistor to be calibrated to perform analog-to-digital conversion on the voltage across the resistor to be calibrated; The resistance calibration circuit according to any one of claims 1 to 8, wherein the resistance calibration circuit is used to calibrate the resistance to be calibrated.

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