Resistance measuring chip and electronic equipment

Abstract

The utility model provides a resistance measurement chip and electronic equipment, the resistance measurement chip is used for measuring the resistance of a resistance module, the resistance measurement chip comprises a constant current source module, the output end of the constant current source module is connected with the resistance module to input a measurement current to the resistance module; the input end of the analog-to-digital conversion module is connected with the resistance module so as to measure a voltage signal output by the resistance module based on the measurement current; wherein the magnitude of the measurement current does not change along with the resistance of the resistance module. According to the invention, there is no need to arrange more voltage-dividing precision resistors on the printed circuit board, so that the problem that the size of the printed circuit board is increased and the printed circuit board is difficult to be applied to compact consumer electronics can be avoided.

Description

Technical Field

[0001] The present application relates to the technical field of integrated circuits, and in particular to a resistance measuring chip and electronic equipment. Background Art

[0002] At present, a resistance sensor is a sensor that converts non-electrical physical quantities such as displacement, pressure, acceleration, torque, and temperature into changes in resistance values. The measurement circuit corresponding to the resistance sensor can obtain the corresponding non-electrical physical quantity by measuring the change in the resistance value of the resistance sensor.

[0003] In the related art, the resistance value of the resistance sensor is mainly measured by a resistance bridge (double-arm) or an upper and lower single-arm resistance voltage divider. However, this method requires a large number of voltage-dividing precision resistors to be set on the printed circuit board, which leads to an increase in the number of components on the printed circuit board and thus an increase in the volume, ultimately making it difficult to apply the resistance sensor to compact consumer electronic products. Utility Model Content

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

[0005] In a first aspect, an embodiment of the present application provides a resistance measurement chip, which is used to measure the resistance of a resistance module. The resistance measurement chip includes: a constant current source module, an output end of the constant current source module is connected to the resistance module to input a measurement current to the resistance module; an analog-to-digital conversion module, an input end of the analog-to-digital conversion module is connected to the resistance module to measure a voltage signal output by the resistance module based on the measurement current; wherein the magnitude of the measurement current does not change with the magnitude of the resistance of the resistance module.

[0006] In a second aspect, the present application provides an electronic device, comprising the resistance measurement chip as described in the first aspect.

[0007] The present application sets a constant current source module and an analog-to-digital conversion module in a resistance measurement chip. The constant current source module can output a measurement current whose current size does not vary with the resistance size of the resistance module, and the analog-to-digital conversion module can measure the voltage signal output by the resistance module based on the measurement current. Therefore, the resistance size of the resistance module can be calculated by the voltage signal and the size of the measurement current, and finally converted to obtain a non-electrical physical quantity (such as temperature or pressure, etc.) to achieve the measurement of the non-electrical physical quantity. Since the present application does not need to set more voltage-dividing precision resistors on the printed circuit board, the problem of increased volume of the printed circuit board and difficulty in application in compact consumer electronic products can be avoided.

[0008] 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

[0009] 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.

[0010] Figure 1 A measurement circuit schematic diagram of a resistance sensor in the related art is shown.

[0011] Figure 2 A schematic diagram of a resistance measurement chip in an embodiment of the present application is shown.

[0012] Figure 3 A circuit diagram of a constant current source module in an embodiment of the present application is shown.

[0013] Figure 4 Another schematic diagram of the resistance measurement chip in the embodiment of the present application is shown.

[0014] Figure 5 Another schematic diagram of the resistance measurement chip in the embodiment of the present application is shown.

[0015] Figure 6 Another schematic diagram of the resistance measurement chip in the embodiment of the present application is shown.

[0016] Figure 7 Another schematic diagram of the resistance measurement chip in the embodiment of the present application is shown.

[0017] Figure 8 Another schematic diagram of the resistance measurement chip in the embodiment of the present application is shown.

[0018] Fig. 9 Another schematic diagram of the resistance measurement chip in the embodiment of the present application is shown.

[0019] Fig.10 Another schematic diagram of the resistance measurement chip in the embodiment of the present application is shown.

[0020] Fig.11 Another schematic diagram of the resistance measurement chip in the embodiment of the present application is shown.

[0021] Among them, there are 100 resistance measurement chips, 10 constant current source modules, 20 analog-to-digital conversion modules, and 30 common-mode voltage bias modules;

[0022] Measuring current I0, voltage signal U0, fully differential analog-to-digital converter ADC1, differential analog-to-digital converter ADC2, fully differential operational amplifier OP, first common pin AIN1, second common pin AIN2, third common pin AIN3, first protection resistor Resd1, second protection resistor Resd2, third protection resistor Resd3, fourth protection resistor Resd4, fifth protection resistor Resd5, sixth protection resistor Resd6. DETAILED DESCRIPTION

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] In the circuit structure provided in the embodiments of the present application, the first node, the second node and other nodes do not represent actual existing components, but represent the junction points of related couplings in the circuit diagram, that is, these nodes are nodes formed by the equivalent junction points of related couplings in the circuit diagram.

[0032] At present, by measuring the change of the resistance value of the resistance sensor through the measurement circuit, the corresponding non-electrical physical quantity (such as displacement, pressure, acceleration, torque, temperature and other non-electrical physical quantities) can be obtained. Taking the resistance measurement of the upper and lower single-arm resistor voltage division as an example, refer to Figure 1 , Figure 1A schematic diagram of a measurement circuit of a resistance sensor in the related art is shown, wherein the resistances R1, R2 and R3 are known resistances, Rx is the resistance to be measured, the resistances R1, R2, R3 and Rx form the bridge arm of the bridge, the DC power supply VCC supplies power to the circuit, and the microcontroller MCU measures the voltage difference Vac between the node A and the node C through the internal analog-to-digital converter. During the operation of the measurement circuit, since the resistance R1 is connected in series with the resistance R3, and the resistance R2 is connected in series with Rx, the voltage flowing through the resistances R1, R2, R3 and Rx can be calculated according to the following formula:

[0033] I1=I2=VCC / (R1+R2)

[0034] I3=Ix=VCC / (R3+Rx)

[0035] Wherein, I1 is the current flowing through the resistor R1, I2 is the current flowing through the resistor R2, I3 is the current flowing through the resistor R3, and Ix is the current flowing through the resistor Rx.

[0036] Therefore, the voltage at point A and the voltage at point C can be calculated as follows:

[0037] Va=VCC / (R1+R2)*R2

[0038] Vc=VCC / (R3+Rx)*R3

[0039] Where Va is the voltage at point A, and Vc is the voltage at point C.

[0040] Finally, the voltage difference between point A and point C can be calculated as follows:

[0041] Vac=VCC / (R1+R2)*R2-VCC / (R3+Rx)*R3

[0042] It can be seen that since the resistance values ​​of resistors R1, R2, and R3 are known, when the MCU measures the voltage difference between point A and point C, the resistance value of the resistor to be measured Rx can be calculated, and then the resistance value of the resistor to be measured Rx can be converted into the corresponding non-electrical physical quantity. However, this method requires setting more voltage-dividing precision resistors on the printed circuit board (for example Figure 1 This leads to the problem of increasing the number of components on the printed circuit board and thus increasing the volume, which ultimately makes it difficult to apply the resistance sensor to compact consumer electronic products.

[0043] To this end, the present application provides a resistance measuring chip and an electronic device. The resistance measuring chip referred to in the present application may be, but is not limited to, a SOC (System on Chip) chip or a SIP (system in package) chip, which are described in detail below.

[0044] First, see Figure 2 , Figure 2 A schematic diagram of a resistance measurement chip 100 in an embodiment of the present application is shown, wherein the resistance measurement chip 100 is used to measure the resistance of a resistance module 1 , and the resistance measurement chip 100 includes a constant current source module 10 and an analog-to-digital conversion module 20 .

[0045] Specifically, the resistance of the resistance module 1 varies with the non-electrical physical quantity in the environment. For example, the resistance module 1 may include a thermistor. When the temperature of the environment changes, the resistance value of the thermistor changes. Therefore, after the resistance measurement chip 100 measures the resistance value of the thermistor, the ambient temperature can be obtained based on the relationship between the thermistor and the temperature, and finally the measurement of the ambient temperature is achieved. For another example, the resistance module 1 may include a varistor. When the voltage applied to the varistor changes, the resistance value of the varistor changes. Therefore, after the resistance measurement chip 100 measures the resistance value of the varistor, the voltage applied to the varistor can be obtained based on the relationship between the varistor and the pressure, and finally the pressure measurement is achieved.

[0046] It can be understood that the resistance module 1 may also include other types of resistors to achieve the measurement of non-electrical physical quantities such as displacement, acceleration, torque, etc.; or, the resistance module 1 may also include thermistors and varistors at the same time, and the pressure and temperature measurement functions can be achieved by switching the measured resistance.

[0047] The output end of the constant current source module 10 is connected to the resistor module 1 to input a measurement current I0 into the resistor module 1, wherein the magnitude of the measurement current I0 does not change with the resistance of the resistor module 1, that is, no matter how the resistance value of the resistor module 1 changes, the current magnitude output by the constant current source module 10 remains unchanged.

[0048] As an example, see Figure 3 , Figure 3A circuit schematic diagram of a constant current source module 10 in an embodiment of the present application is shown, wherein the constant current source module 10 includes an operational amplifier OP0, a resistor R1, a resistor R2, a first NMOS tube MN1, a first PMOS tube MP1 and a second PMOS tube MP2, the inverting input terminal of the operational amplifier OP0 is connected to the reference voltage VBG, the non-inverting input terminal of the operational amplifier OP0 is connected to the node M between the resistor R1 and the resistor R2, the output terminal of the operational amplifier OP0 is connected to the gate of the first NMOS tube MN1, and since the drain of the first NMOS tube MN1 is connected to the resistor R1, the inverting input terminal and the output terminal of the operational amplifier are connected to form negative feedback, and according to the virtual short and virtual break characteristics of the operational amplifier, the voltage of the node M is equal to the reference voltage VBG, that is, the current flowing through the first PMOS tube MP1 is: I1=VBG / R2. At the same time, since the gates of the first PMOS tube MP1 and the second PMOS tube MP2 are connected to each other, and the gate and drain of the first PMOS tube MP1 are short-circuited, the first PMOS tube MP1 and the second PMOS tube MP2 form a current mirror, so that the current output by the drain of the second PMOS tube is always equal to the current flowing through the first PMOS tube MP1, that is, I0=I1=VBG / R2, and finally the purpose of keeping the current output by the constant current source module 10 unchanged is achieved.

[0049] It can be understood that the above embodiment uses the operational amplifier type constant current source module 10 as an exemplary illustration only. In fact, other types of constant current source modules 10 can also be used, such as constant current source modules 10 of the Zener diode constant current or the current mirror type mirror constant current.

[0050] The input end of the analog-to-digital conversion module 20 is connected to the resistor module 1 to measure the voltage signal U0 output by the resistor module 1 based on the measurement current I0. In some embodiments of the present application, the voltage signal U0 may be a single-ended signal. For example, when one end of the resistor module 1 is directly grounded, the voltage signal U0 refers to the voltage at one end of the resistor module 1 into which the measurement current I0 flows. In some embodiments of the present application, the voltage signal U0 may be a differential signal, that is, the voltage signal U0 refers to the differential signal at both ends of the resistor module 1.

[0051] Exemplarily, the analog-to-digital conversion module 20 includes but is not limited to a successive approximation register ADC (SAR ADC), a Sigma-Delta ADC (SD ADC), or a hybrid analog-to-digital converter consisting of a successive approximation register ADC and a Sigma-Delta ADC.

[0052] In the embodiment of the present application, the present application sets a constant current source module 10 and an analog-to-digital conversion module 20 in the resistance measurement chip 100. The constant current source module 10 can output a measurement current I0 whose current size does not change with the resistance size of the resistance module 1, and the analog-to-digital conversion module 20 can measure the voltage signal U0 output by the resistance module 1 based on the measurement current I0. Therefore, the resistance size of the resistance module 1 can be calculated by the size of the voltage signal U0 and the measurement current I0, and finally the non-electrical physical quantity (such as temperature or pressure, etc.) and the resistance size of the resistance module 1 can be used to measure the non-electrical physical quantity. The relationship between the non-electrical physical quantity (such as temperature or pressure, etc.) and the resistance size of the resistance module 1 can be used to achieve the measurement of the non-electrical physical quantity. Since the present application does not need to set more voltage-dividing precision resistors on the printed circuit board, the problem of increasing the volume of the printed circuit board and being difficult to apply to compact consumer electronic products can be avoided.

[0053] In some embodiments of the present application, the reference voltages of the constant current source module 10 and the analog-to-digital conversion module 20 are from the same source. For example, the constant current source module 10 and the analog-to-digital conversion module 20 can be connected to the output end of the same bandgap reference circuit, so that the constant current source module 10 and the analog-to-digital conversion module 20 operate under the reference voltage output by the same bandgap reference circuit, which is beneficial to reducing the bandgap reference circuit inside the resistance measurement chip 100 and the chip manufacturing cost.

[0054] In some embodiments of the present application, for example, for an embodiment in which the voltage signal U0 is a differential signal, see Figure 4 , Figure 4 Another schematic diagram of the resistance measurement chip 100 in the embodiment of the present application is shown, wherein the analog-to-digital conversion module 20 includes a fully differential analog-to-digital converter ADC1, a first differential input terminal of the fully differential analog-to-digital converter ADC1 is connected to a first terminal of the resistance module 1, and a second differential input terminal of the fully differential analog-to-digital converter ADC1 is connected to a second terminal of the resistance module 1, so as to measure the voltage difference across the resistance module 1 through the fully differential analog-to-digital converter ADC1, and finally calculate the resistance value of the resistance module 1 in combination with the measured current I0 and the voltage signal U0. Exemplarily, the fully differential analog-to-digital converter ADC1 may include a differential input successive approximation analog-to-digital converter or a differential input Σ-Δ analog-to-digital converter.

[0055] In some embodiments of the present application, see Figure 5 , Figure 5Another schematic diagram of the resistance measuring chip 100 in an embodiment of the present application is shown, wherein the analog-to-digital conversion module 20 further includes a fully differential operational amplifier OP; a first input terminal of the fully differential operational amplifier OP is connected to a first terminal of the resistance module 1, and a second input terminal of the fully differential operational amplifier OP is connected to a first terminal of the resistance module 1; a first differential input terminal of the fully differential analog-to-digital converter ADC1 is connected to an inverting output terminal of the fully differential operational amplifier OP, and a second differential input terminal of the fully differential analog-to-digital converter ADC1 is connected to a non-inverting output terminal of the fully differential operational amplifier OP.

[0056] It should be noted that the fully differential operational amplifier OP amplifies the voltage signal U0 and then measures it through the fully differential analog-to-digital converter ADC1, which is beneficial to reducing the measurement error of the voltage signal U0. For example, when the measurement error of the fully differential analog-to-digital converter ADC1 is △U, if the voltage signal U0 is measured directly, the measurement result of the fully differential analog-to-digital converter ADC1 is U0+△U, that is, the measurement error of the voltage signal U0 is △U; and when the fully differential operational amplifier OP amplifies the voltage signal U0 by N times, the measurement result of the fully differential analog-to-digital converter ADC1 is NU0+△U, so the measurement result of the voltage signal U0 after conversion is U0+△U / N, that is, the measurement error of the voltage signal U0 is △U / N. It can be seen that the measurement error of the voltage signal U0 is reduced by N times. Therefore, amplifying the voltage signal U0 through the fully differential operational amplifier OP and then measuring it with the fully differential analog-to-digital converter ADC1 is beneficial to reducing the measurement error of the voltage signal U0.

[0057] It can be understood that the first input terminal of the fully differential operational amplifier OP may refer to the non-inverting input terminal of the fully differential operational amplifier OP, and the second input terminal of the fully differential operational amplifier OP may refer to the inverting input terminal of the fully differential operational amplifier OP; or, the first input terminal of the fully differential operational amplifier OP may refer to the inverting input terminal of the fully differential operational amplifier OP, and the second input terminal of the fully differential operational amplifier OP may refer to the non-inverting input terminal of the fully differential operational amplifier OP.

[0058] In some embodiments of the present application, see Figure 6 , Figure 6Another schematic diagram of the resistance measurement chip 100 in the embodiment of the present application is shown, wherein the resistance measurement chip 100 further includes a common mode voltage bias module 30 outputting a common mode voltage; the output end of the constant current source module 10 is connected to the first end of the resistance module 1 to input the measurement current I0 to the resistance module 1, and the output end of the common mode voltage bias module 30 is connected to the second end of the resistance module 1 to bias the second end of the resistance module 1 at the common mode voltage. Specifically, for the embodiment in which the voltage signal U0 is a differential signal, under the action of the common mode voltage bias module 30, the voltage signal U0 has a common mode voltage VCM. By controlling the magnitude of the common mode voltage VCM, the fully differential operational amplifier OP can be placed in the optimal working area, thereby facilitating the improvement of the accuracy of the amplification factor of the voltage signal U0 by the fully differential operational amplifier OP, and ultimately achieving the purpose of improving the measurement accuracy of the voltage signal U0.

[0059] Understandably, if Figure 6 As shown, the constant current source module 10 can also be provided with a first switch S1, and the common mode voltage bias module 30 can also be provided with a second switch S2 to control whether the constant current source module 10 outputs the measurement current I0, and whether the common mode voltage bias module 30 outputs the common mode voltage VCM.

[0060] In some embodiments of the present application, see Figure 7 , Figure 7 Another schematic diagram of the resistance measuring chip 100 in an embodiment of the present application is shown, wherein the resistance measuring chip 100 has a first common pin AIN1 and a second common pin AIN2; the first input end of the fully differential operational amplifier OP and the output end of the constant current source module 10 are connected to the first common pin AIN1, and the second input end of the fully differential operational amplifier OP and the output end of the common mode voltage bias module 30 are connected to the second common pin AIN2; the first end of the resistance module 1 is connected to the first common pin AIN1, and the second end of the resistance module 1 is connected to the second common pin AIN2.

[0061] It should be noted that, in general, the resistance measurement chip 100 needs to set four pins for the first input end of the fully differential operational amplifier OP, the output end of the constant current source module 10, the second input end of the fully differential operational amplifier, and the output end of the common mode voltage bias module 30, respectively, so as to input the current signal to the resistance module 1 and obtain the voltage signal U0 generated by the resistance module 1. However, this leads to the problem of too many chip pins. At the same time, since the resistance module 1 needs to be connected to four pins, the connection area between the resistance module 1 and the pins will be larger, which reduces the resistance measurement chip 100's ability to resist current interference. In the above embodiment, since the first input end of the fully differential operational amplifier OP and the output end of the constant current source module 10 share the first common pin AIN1, and the second input end of the fully differential operational amplifier OP and the output end of the common mode voltage bias module 30 share the second common pin AIN2, the number of pins connected between the resistance measurement chip 100 and the resistance module 1 is reduced to two, thereby reducing the connection area between the resistance module 1 and the chip pins, which is ultimately conducive to improving the resistance measurement chip 100's ability to resist current interference.

[0062] In some embodiments of the present application, see Figure 8 , Figure 8 Another schematic diagram of the resistance measuring chip 100 in an embodiment of the present application is shown, wherein the resistance measuring chip 100 further includes a first protection resistor Resd1, a second protection resistor Resd2, a third protection resistor Resd3 and a fourth protection resistor Resd4; one end of the first protection resistor Resd1 is connected to the first common pin AIN1, and the other end is connected to the output end of the constant current source module 10; one end of the second protection resistor Resd2 is connected to the first common pin AIN1, and the other end is connected to the first input end of the fully differential operational amplifier OP; one end of the third protection resistor Resd3 is connected to the second common pin AIN2, and the other end is connected to the output end of the common-mode voltage bias module 30; one end of the fourth protection resistor Resd4 is connected to the second common pin AIN2, and the other end is connected to the second input end of the fully differential operational amplifier OP. Among them, the first protection resistor Resd1, the second protection resistor Resd2, the third protection resistor Resd3 and the fourth protection resistor Resd4 have electrostatic protection function and surge protection function, so as to prevent the first input end of the fully differential operational amplifier OP, the output end of the constant current source module 10, the second input end of the fully differential operational amplifier OP and the output end of the common mode voltage bias module 30 from being affected by external static electricity, and can reduce the risk of the external interface of the resistance measurement chip 100 being damaged due to ESD surge.

[0063] In some embodiments of the present application, for example, the voltage signal U0 is a single-ended signal, see Fig. 9 , Fig. 9 Another schematic diagram of the resistance measuring chip 100 in an embodiment of the present application is shown, wherein the analog-to-digital conversion module 20 includes a differential analog-to-digital converter ADC2, the input end of the differential analog-to-digital converter ADC2 is connected to the first end of the resistance module 1, and the second end of the resistance module 1 is connected to the ground end, so that the first end of the resistance module 1 can generate a single-ended voltage signal U0 relative to the ground end, and the voltage signal U0 can be measured using the differential analog-to-digital converter ADC2 with a single-ended input.

[0064] It is understandable that a differential operational amplifier may also be provided to amplify the single-ended voltage signal U0 , which is helpful to reduce the measurement error of the voltage signal U0 when the differential analog-to-digital converter ADC2 measures the single-ended voltage signal U0 .

[0065] In some embodiments of the present application, see Fig.10 , Fig.10 Another schematic diagram of the resistance measurement chip 100 in the embodiment of the present application is shown, wherein the resistance measurement chip 100 has a third common pin AIN3; the input end of the differential analog-to-digital converter ADC2 and the output end of the constant current source module 10 are connected to the third common pin AIN3, and the first end of the resistance module 1 is connected to the third common pin AIN3. Similarly, since the input end of the differential analog-to-digital converter ADC2 and the output end of the constant current source module 10 share the third common pin AIN3, the number of pins connected between the resistance measurement chip 100 and the resistance module 1 is reduced, thereby reducing the area of ​​the connection region between the resistance module 1 and the pins, which is ultimately beneficial to improving the resistance measurement chip 100's ability to resist current-type interference.

[0066] In some embodiments of the present application, see Fig.11 , Fig.11 Another schematic diagram of the resistance measurement chip 100 in the embodiment of the present application is shown, wherein the resistance measurement chip 100 further includes a fifth protection resistor Resd5 and a sixth protection resistor Resd6; one end of the fifth protection resistor Resd5 is connected to the third common pin AIN3, and the other end is connected to the output end of the constant current source module 10; one end of the sixth protection resistor Resd6 is connected to the third common pin AIN3, and the other end is connected to the input end of the differential analog-to-digital converter ADC2. Similarly, the fifth protection resistor Resd5 and the sixth protection resistor Resd6 have electrostatic protection function and surge protection function, so that the input end of the differential operational amplifier and the output end of the constant current source module 10 can be prevented from being affected by external static electricity, and the risk of the external interface of the resistance measurement chip 100 being damaged by ESD surge can be reduced.

[0067] The embodiment of the present application also provides an electronic device, which includes a device body and a resistance measurement chip 100 as described above, which is arranged in the device body. The electronic device can 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 center console, 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.

[0068] 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 measurement chip, characterized in that: The resistance measurement chip is used to measure the resistance of the resistance module, and the resistance measurement chip includes: A constant current source module, wherein an output end of the constant current source module is connected to the resistance module to input a measurement current to the resistance module; an analog-to-digital conversion module, wherein an input terminal of the analog-to-digital conversion module is connected to the resistance module to measure a voltage signal output by the resistance module based on the measurement current; The magnitude of the measurement current does not vary with the magnitude of the resistance of the resistance module.

2. The resistance measuring chip according to claim 1, characterized in that: The analog-to-digital conversion module includes a fully differential analog-to-digital converter; The first differential input terminal of the fully differential analog-to-digital converter is connected to the first terminal of the resistor module, and the second differential input terminal of the fully differential analog-to-digital converter is connected to the second terminal of the resistor module.

3. The resistance measuring chip according to claim 2, characterized in that: The analog-to-digital conversion module also includes a fully differential operational amplifier; The first input terminal of the fully differential operational amplifier is connected to the first end of the resistor module, and the second input terminal of the fully differential operational amplifier is connected to the first end of the resistor module; The first differential input terminal of the fully differential analog-to-digital converter is connected to the inverting output terminal of the fully differential operational amplifier, and the second differential input terminal of the fully differential analog-to-digital converter is connected to the non-inverting output terminal of the fully differential operational amplifier.

4. The resistance measuring chip according to claim 3, characterized in that: The resistance measurement chip also includes a common mode voltage bias module that outputs a common mode voltage; The output end of the constant current source module is connected to the first end of the resistor module to input a measurement current to the resistor module, and the output end of the common mode voltage bias module is connected to the second end of the resistor module to bias the second end of the resistor module at the common mode voltage.

5. The resistance measuring chip according to claim 4, characterized in that: The resistance measurement chip has a first common pin and a second common pin; The first input end of the fully differential operational amplifier and the output end of the constant current source module are connected to the first common pin, and the second input end of the fully differential operational amplifier and the output end of the common mode voltage bias module are connected to the second common pin; The first end of the resistance module is connected to the first common pin, and the second end of the resistance module is connected to the second common pin.

6. The resistance measuring chip according to claim 5, characterized in that: The resistance measurement chip also includes a first protection resistor, a second protection resistor, a third protection resistor and a fourth protection resistor; One end of the first protection resistor is connected to the first common pin, and the other end is connected to the output end of the constant current source module; One end of the second protection resistor is connected to the first common pin, and the other end is connected to the first input end of the fully differential operational amplifier; One end of the third protection resistor is connected to the second common pin, and the other end is connected to the output end of the common mode voltage bias module; One end of the fourth protection resistor is connected to the second common pin, and the other end is connected to the second input end of the fully differential operational amplifier.

7. The resistance measuring chip according to claim 1, characterized in that: The analog-to-digital conversion module includes a differential analog-to-digital converter; The input end of the differential analog-to-digital converter is connected to the first end of the resistor module, and the second end of the resistor module is connected to the ground end.

8. The resistance measuring chip according to claim 7, characterized in that: The resistance measurement chip has a third common pin; The input end of the differential analog-to-digital converter and the output end of the constant current source module are connected to the third common pin, and the first end of the resistance module is connected to the third common pin.

9. The resistance measuring chip according to claim 8, characterized in that: The resistance measurement chip also includes a fifth protection resistor and a sixth protection resistor; One end of the fifth protection resistor is connected to the third common pin, and the other end is connected to the output end of the constant current source module; One end of the sixth protection resistor is connected to the third common pin, and the other end is connected to the input end of the differential analog-to-digital converter.

10. An electronic device, characterized in that: The invention comprises the resistance measuring chip as claimed in any one of claims 1 to 9.

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