CN113865757B - Detection circuit, detection method and electronic equipment of piezoresistive pressure sensor - Google Patents
Detection circuit, detection method and electronic equipment of piezoresistive pressure sensor Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L25/00—Testing or calibrating of apparatus for measuring force, torque, work, mechanical power, or mechanical efficiency
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L27/00—Testing or calibrating of apparatus for measuring fluid pressure
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/02—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in ohmic resistance, e.g. of potentiometers, electric circuits therefor, e.g. bridges, amplifiers or signal conditioning
- G01L9/06—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in ohmic resistance, e.g. of potentiometers, electric circuits therefor, e.g. bridges, amplifiers or signal conditioning of piezo-resistive devices
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/55—Testing for incorrect line connections
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Abstract
The application discloses a detection circuit, a detection method and electronic equipment of a piezoresistive pressure sensor, which belong to the technical field of power electronics, wherein the piezoresistive pressure sensor adopts a Wheatstone bridge circuit, and comprises a first voltage output end and a second voltage output end, the first voltage output end is connected with a first voltage input pin of a processing chip, and the second voltage output end is connected with a second voltage input pin of the processing chip; the detection circuit of the piezoresistive pressure sensor comprises at least one detection unit of a first detection unit, a second detection unit, a third detection unit and a fourth detection unit; each detection unit comprises a current source and a switch connected with the current source in series, and the control end of the switch is connected with the processing chip.
Description
Technical Field
The application belongs to the technical field of power electronics, and particularly relates to a detection circuit, a detection method and electronic equipment of a piezoresistive pressure sensor.
Background
The pressure sensor is a key sensing component of the mobile phone and the wearable device, and the number and the demand of the pressure sensor are increased under various innovative applications of artificial intelligence. Because of the limited space available on cell phones and wearable devices, most sensors employ MEMS (Microelectromechanical Systems) pressure sensors to achieve miniaturization, with piezoresistive MEMS pressure sensors being the most common.
In application, the piezoresistive pressure sensor must be connected with a signal processing chip by wire bonding, and the signal processing circuit processes the signal of the output end of the piezoresistive pressure sensor after the signal is sent to the signal processing chip. However, in the mass production process, the bridge arm resistance of the piezoresistive pressure sensor is wrong or the wire bonding is wrong, so that the problems of reduced signal accuracy, reduced product yield, increased cost and the like are caused.
Content of the application
The embodiment of the application aims to provide a detection circuit, a detection method and electronic equipment of a piezoresistive pressure sensor, which can detect the problems of error resistance and circuit connection of a piezoresistive pressure sensor bridge arm.
In order to solve the technical problems, the application is realized as follows:
in a first aspect, an embodiment of the present application provides a detection circuit of a piezoresistive pressure sensor, where the piezoresistive pressure sensor uses a wheatstone bridge circuit, and the piezoresistive pressure sensor includes a first voltage output end and a second voltage output end, where the first voltage output end is connected to a first voltage input pin of a processing chip, and the second voltage output end is connected to a second voltage input pin of the processing chip; the detection circuit comprises at least one detection unit of a first detection unit, a second detection unit, a third detection unit and a fourth detection unit; each detection unit comprises a current source and a switch connected with the current source in series, and the control end of the switch is connected with the processing chip; the first detection unit is used for being connected between the first voltage output end and a first grounding end; the second detection unit is a detection unit used for being connected between a first power end and the first voltage output end; the third detection unit is a detection unit used for being connected between the second voltage output end and the first grounding end; the fourth detection unit is a detection unit used for being connected between the first power end and the first voltage output end.
Further, the detection circuit comprises at least two detection units of the first detection unit, the second detection unit, the third detection unit and the fourth detection unit, wherein the at least two detection units comprise a detection unit connected with the first voltage output end and a detection unit connected with the second voltage output end.
Further, the detection circuit includes the first detection unit, the second detection unit, the third detection unit, and the fourth detection unit.
Further, the switch is a switch tube.
Further, the current values of the current sources of the detection units in the detection circuit are equal.
Further, the detection circuit further comprises a reference current circuit, and the current source of each detection unit in the detection circuit is a mirror current source corresponding to the reference current circuit.
Further, the reference current circuit comprises an operational amplifier, a first PMOS tube, a second PMOS tube, a first NMOS tube, a second NMOS tube and a resistor; the first input end of the operational amplifier is a reference power supply input end, the second input end of the operational amplifier is connected with the source electrode of the first NMOS tube, the output end of the operational amplifier is connected with the grid electrode of the first NMOS tube, and the resistor is connected between the second input end and the first grounding end; the source electrode of the first PMOS tube and the source electrode of the second PMOS tube are connected with the first power supply end, the drain electrode of the first PMOS tube is connected with the drain electrode of the first NMOS tube, and the grid electrode of the first PMOS tube is connected with the drain electrode of the first PMOS tube and the grid electrode of the second PMOS tube; the drain electrode of the second PMOS tube is connected with the drain electrode of the second NMOS tube, the source electrode of the second NMOS tube is connected with the first grounding end, and the grid electrode of the second NMOS tube is connected with the drain electrode of the second NMOS tube; the current sources of the second detection unit and the fourth detection unit correspond to the mirror current sources of the first PMOS tube; the current sources of the first detection unit and the third detection unit are mirror current sources corresponding to the second NMOS tube.
In a second aspect, an embodiment of the present application provides a detection method based on the detection circuit in any one of the first aspects, which is characterized by including: a detection unit for determining the detection state of the detection circuit; under the condition that one detection unit enters a detection state, the other detection units are in a non-detection state that a switch is disconnected; for a detection unit entering a detection state, firstly controlling a switch of the detection unit to be turned off, and then controlling the switch of the detection unit to be turned on; the detection unit and a pressure sensing piece on a bridge arm of the piezoresistive pressure sensor are connected in series between a first power end and a first grounding end; under the condition that the switch is disconnected, respectively acquiring a first voltage value of a first voltage output end and a second voltage value of a second voltage output end of the piezoresistive pressure sensor, and calculating a first voltage difference value between the second voltage value and the first voltage value; under the condition that the switch is conducted, a third voltage value of the first voltage output end and a fourth voltage value of the second voltage output end are respectively obtained, and a second voltage difference value between the fourth voltage value and the third voltage value is calculated; comparing the first voltage difference with the second voltage difference to obtain a comparison result; according to the comparison result, the current value of the current source of the detection unit and the standard resistance value of the pressure sensing piece, a first detection result of whether the connection between at least one voltage output end and the processing chip is wrong or not and a second detection result of whether the actual resistance value of the pressure sensing piece is consistent with the standard resistance value or not are obtained and output; wherein the at least one voltage output terminal is at least one of the first voltage output terminal and the second voltage output terminal.
In a third aspect, an embodiment of the present application provides an electronic device, including: a processing chip; the piezoresistive pressure sensor adopts a Wheatstone bridge circuit, and comprises a first voltage output end and a second voltage output end, wherein the first voltage output end is connected with a first voltage input pin of the processing chip, and the second voltage output end is connected with a second voltage input pin of the processing chip; and the detection circuit is as claimed in any one of claims 1 to 7, wherein a control end of a switch of the detection unit in the detection circuit is connected with a control signal output pin of the processing chip, and different switches correspond to different control signal output pins.
Further, the processing chip is configured to implement the method according to the second aspect under the control of a computer program stored in a memory.
In the embodiment of the application, a detection circuit and a reference current circuit for providing a current source for the detection circuit are arranged between the output ends INP and INN of the piezoresistive pressure sensor so as to judge whether the piezoresistive pressure sensor is correctly connected and whether the resistance value of a pressure sensing piece of the piezoresistive pressure sensor is problematic, thereby assisting production and improving the signal accuracy and the product qualification rate of the piezoresistive pressure sensor.
Drawings
FIG. 1 is a schematic diagram of a piezoresistive pressure sensor according to the present embodiment;
FIG. 2 is a diagram of a detection circuit of a piezoresistive pressure sensor according to the present embodiment;
Fig. 3 is a schematic diagram of the operation of a first detection circuit in the detection circuit according to the present embodiment;
fig. 4 is a schematic diagram of the operation of a second detection circuit in the detection circuit according to the present embodiment;
fig. 5 is a reference current circuit in the detection circuit according to the present embodiment;
fig. 6 is a flowchart of a detection method of the detection circuit according to the present embodiment;
Fig. 7 is a schematic structural diagram of an electronic device according to the present embodiment.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the application may be practiced otherwise than as specifically illustrated or described herein. Furthermore, in the description and claims, "and/or" means at least one of the connected objects, and the character "/", generally means that the associated object is an "or" relationship.
The detection circuit, the detection method and the electronic device of the piezoresistive pressure sensor provided by the embodiment of the application are described in detail through specific embodiments and application scenes thereof with reference to the accompanying drawings.
The piezoresistive pressure sensor provided by the embodiment adopts a wheatstone bridge circuit, the piezoresistive pressure sensor comprises a first voltage output end INN and a second voltage output end INP, the first voltage output end INN is connected with a first voltage input pin of a processing chip, the second voltage output end INP is connected with a second voltage input pin of the processing chip, so that the processing chip can receive a voltage signal output by the piezoresistive pressure sensor, and the processing chip is used for processing the voltage signal output by the piezoresistive pressure sensor.
Referring to fig. 1, the piezoresistive pressure sensor includes four pressure sensing elements, the four pressure sensing elements are connected to form a wheatstone bridge circuit, wherein a first pressure sensing element RA is connected between a second power input terminal VDDB and a first voltage output terminal INN, a second pressure sensing element RB is connected between the first voltage output terminal INN and a second ground terminal, a third pressure sensing element RC is connected between the second power input terminal VDDB and a second voltage output terminal INP, and a fourth pressure sensing element RD is connected between the second voltage output terminal INP and the second ground terminal. The working principle is as follows: when the pressure changes, the RA and RD resistance values are increased from R to R+ΔR, while the RB and RC resistance values are decreased from R to R- ΔR, wherein R is RA, RB, RC, RD, and ΔR is the resistance change value.
Based on the fact that the piezoresistive pressure sensor has the bridge arm pressure sensing element with the wrong resistance and the wrong line connection, the embodiment provides a detection circuit of the piezoresistive pressure sensor, and referring to fig. 2, the detection circuit comprises at least one detection unit of a first detection unit, a second detection unit, a third detection unit and a fourth detection unit. Each detection unit comprises a current source and a switch connected with the current source in series, and the control end of the switch is connected with the processing chip. Referring to fig. 2, the first detection unit includes a current source IA and a switch SA, the second detection unit includes a current source IB and a switch SB, the third detection unit includes a current source IC and a switch SC, and the fourth detection unit includes a current source ID and a switch SD.
The first detection unit, the second detection unit, the third detection unit and the fourth detection unit are used for detecting whether the resistance value and the connecting line of the piezoresistive pressure sensor are wrong, the current source is used for providing detection current for each detection unit, and the switch is used for controlling the on-off of the current source.
The first detection unit is used for being connected between the first voltage output end and the first grounding end; the second detection unit is used for being connected between the first power end and the first voltage output end; the third detection unit is used for being connected between the second voltage output end and the first grounding end; the fourth detection unit is a detection unit used for being connected between the first power end and the first voltage output end. Referring to fig. 2, a first detection unit is used to detect whether an RA connection circuit fails, a second detection unit is used to detect whether an RB connection circuit fails, a third detection unit is used to detect whether an RC connection circuit fails, and a fourth detection unit is used to detect whether an RD connection circuit fails.
In a possible embodiment, the detection circuit includes at least one of the first detection unit, the second detection unit, the third detection unit and the fourth detection unit, so that the detection of the piezoresistive sensor can be achieved, and of course, the detection of each pressure sensing element can be achieved by selecting a switch, such as a single-pole multi-throw switch, to achieve the circuit connection between the at least one detection unit and each pressure sensing element.
In a possible embodiment, the detection circuit may further comprise at least two of a first detection unit, a second detection unit, a third detection unit and a fourth detection unit, wherein the at least two detection units comprise a detection unit connected to the first voltage output terminal and a detection unit connected to the second voltage output terminal. That is, each voltage output end corresponds to one detection unit, so that whether the pressure sensing piece breaks down or not can be accurately detected.
In a possible embodiment, the detection circuit comprises a first detection unit, a second detection unit, a third detection unit and a fourth detection unit, that is to say one detection unit for each pressure-sensitive element.
In this embodiment, the switch of each detection unit is a switch tube, such as a PMOS tube or an NMOS tube, and the connection and disconnection of the current source are realized by using the circuit on characteristics of the PMOS tube or the NMOS tube.
In this embodiment, since the resistances of each of the voltage sensing elements are the same, the current values of the current sources of the detection units in the detection circuit of this embodiment are equal, for example, ia=ib=ic=id=0.25 uA, in order to ensure the stability of the circuit and the convenience of calculation.
The detection principle of each detection unit is described below:
Referring to fig. 3, fig. 3 is a diagram illustrating the operation of the first detection unit start switch SA. When SA is off, IA flows through RA, which may result in an increase in pressure drop va=ia×ra, assuming ia=0.25 ua, ra=4k, va=0.25 ua×4k=1 mV. By utilizing the difference between the normal signal INP-INN and the signal INP-INN+VA after the IA current flows, the read value of the processing chip can be used for judging whether the piezoresistive pressure sensor is normally connected to the processing chip or whether the bridge arm resistance RA is abnormal.
Similarly, referring to fig. 4, fig. 4 is a diagram illustrating the operation of the second detection unit start switch SB. When SB is off, IB flows through RB, which may result in an increase in voltage drop vb=ib×rb, assuming ib=0.25 uA and rb=4kΩ, then vb=0.25 ua×4kΩ=1 mV. By utilizing the difference between the normal signal INP-INN and the signal INP-INN-VB after the IB current flows, the read value of the chip can be used for judging whether the piezoresistive pressure sensor is normally connected to the chip or whether the bridge arm resistance RB is abnormal.
The detection principle of the third detection unit is the same as that of the first detection unit, and the detection principle of the fourth detection unit is the same as that of the second detection unit, and thus, the description thereof is omitted.
In this embodiment, the detection circuit further includes a reference current circuit, where the reference current circuit is configured to provide a current source for each detection unit in the detection circuit, and referring to fig. 5, the current source of each detection unit in the detection circuit is a mirror current source corresponding to the reference current circuit.
In this embodiment, the reference current circuit includes an operational amplifier OPAMP, a first PMOS transistor MP0, a second PMOS transistor MP1, a first NMOS transistor MN0, a second NMOS transistor MN1, and a resistor R1. The first input end of the operational amplifier is a reference power input end, the reference power input end inputs voltage VREF, the second input end of the operational amplifier is connected with the source electrode of the first NMOS tube MN0, the output end of the operational amplifier is connected with the grid electrode of the first NMOS tube MN0, and the resistor R1 is connected between the second input end of the OPAMP and the first grounding end; the source electrode of the first PMOS tube MP0 and the source electrode of the second PMOS tube MP1 are connected with a first power supply end, the drain electrode of the first PMOS tube MP0 is connected with the drain electrode of the first NMOS tube MN0, and the grid electrode of the first PMOS tube MP0 is connected with the drain electrode of the first PMOS tube MP0 and the grid electrode of the second PMOS tube MP 1; the drain electrode of the second PMOS tube MP1 is connected with the drain electrode of the second NMOS tube MN1, the source electrode of the second NMOS tube MN1 is connected with the first grounding end, and the grid electrode of the second NMOS tube MN1 is connected with the drain electrode of the second NMOS tube MN 1.
The current source IB of the second detection unit and the current source ID of the fourth detection unit correspond to the mirror current source of the first PMOS tube; the current source IA of the first detection unit and the current source of the third detection unit are mirror current sources corresponding to the second NMOS transistor.
The reference current circuit further comprises a third PMOS tube MP2, a fourth PMOS tube MP3, sources of MP2 and MP3 are connected with the first power supply end, grids of MP2 and MP3 are connected with the grid of the second PMOS tube, a drain electrode of MP2 outputs an IB current source, and a drain electrode of MP3 outputs an ID current source.
The reference current circuit further comprises a third NMOS tube MN2 and a fourth NMOS tube MN3, sources of the MN2 and the MN3 are connected with the first grounding end, gates of the MN2 and the MN3 are connected with a gate of the second NMOS tube, a drain electrode of the MN2 outputs an IA current source, and a drain electrode of the MN3 outputs an IC current source.
In this embodiment, OPAMP, MN0, R1 are used to form a negative feedback circuit, VREF is input to the negative feedback circuit to generate the reference current ir=vref/R1. MP0, MP1, MP2, MP3 are PMOS current mirror circuits, which multiply-amplify IR to generate required IB and ID currents for the second detection unit and the fourth detection unit. MN1, MN2 and MN3 are NMOS current mirror circuits, which multiply and amplify IR2 to generate the required IA and IC currents for the first detection unit and the third detection unit. And (3) using.
In this embodiment, the first power source connected to the first power source terminal is VDD, and the first ground terminal is a ground port of the circuit.
Above, for the detection circuit of the piezoresistive pressure sensor provided in this embodiment, a detection circuit and a reference current circuit for providing a current source for the detection circuit are disposed between output ends INP and INN of the piezoresistive pressure sensor, so as to determine whether the piezoresistive pressure sensor is connected correctly and whether the resistance of a pressure sensing element of the piezoresistive pressure sensor is problematic, thereby assisting production and improving signal accuracy and product yield of the piezoresistive pressure sensor.
The present embodiment also provides a detection method of a detection circuit, referring to fig. 6, the method includes:
s6100, determining a detection unit in the detection circuit entering the detection state.
Under the condition that one detection unit enters a detection state, the other detection units are in a non-detection state that a switch is opened, and the detection unit entering the detection state can be any one of the first detection unit, the second detection unit, the third detection unit and the fourth detection unit.
S6200, for the detection unit entering the detection state, firstly controlling the switch of the detection unit to be turned off and then controlling the switch of the detection unit to be turned on.
The detection unit and the pressure sensing element on one bridge arm of the piezoresistive pressure sensor are connected in series between the first power supply terminal and the first ground terminal, for example, IA, SA, and RA in fig. 3 are connected in series between VDDB and ground.
S6300, under the condition that a switch is opened, respectively acquiring a first voltage value of a first voltage output end and a second voltage value of a second voltage output end of the piezoresistive pressure sensor, and calculating a first voltage difference value between the second voltage value and the first voltage value, wherein the first voltage difference value is INP-INN referring to FIG. 2.
S6400, under the condition that the switch is turned on, respectively obtaining a third voltage value of the first voltage output end and a fourth voltage value of the second voltage output end, and calculating a second voltage difference value between the fourth voltage value and the third voltage value, referring to FIG. 3, when the detection unit entering the detection state is the first detection unit, referring to FIG. 3, the second voltage difference value is INP-INN+VA.
S6500, comparing the first voltage difference value with the second voltage difference value to obtain a comparison result.
In this embodiment, the first voltage difference is a voltage difference when the detection unit is not connected, that is, a normal output value of the piezoresistive pressure sensor, if the first voltage difference is the same as a theoretical normal output value, it indicates that the connection between the piezoresistive pressure sensor and the processing chip is normal, the comparison result is that the circuit between the piezoresistive pressure sensor and the processing chip is normal, otherwise, if the first voltage difference is different from the theoretical normal output value, it indicates that the connection between the piezoresistive pressure sensor and the processing chip is abnormal, and the comparison result is that the circuit between the piezoresistive pressure sensor and the processing chip is abnormal.
In this embodiment, the second voltage difference is a voltage difference when connected to the detecting unit, and is used for detecting whether the resistance of the pressure sensing element of the piezoresistive pressure sensor is normal under the condition of fixed current, if the second voltage difference is the same as the normal output value under the theoretical standard resistance, it indicates that the resistance of the pressure sensing element of the piezoresistive pressure sensor is normal, and if the comparison result is that the resistance of the pressure sensing element of the piezoresistive pressure sensor is normal. Otherwise, if the second voltage difference is different from the normal output value of the voltage difference under the theoretical standard resistance, the abnormal resistance of the pressure sensing piece of the piezoresistive pressure sensor is indicated, and the comparison result is that the resistance of the pressure sensing piece of the piezoresistive pressure sensor is abnormal.
S6500, according to the comparison result, the current value of the current source of the detection unit and the standard resistance value of the pressure sensing piece, obtaining and outputting a first detection result of whether the connection between at least one voltage output end and the processing chip is wrong or not, and a second detection result of whether the actual resistance value of the pressure sensing piece is consistent with the standard resistance value or not.
Based on the above step S6400, the first detection result indicates that the circuit connection between the piezoresistive pressure sensor and the processing chip is normal, or that the circuit connection between the piezoresistive pressure sensor and the processing chip is abnormal. The second detection result represents that the resistance value of the pressure sensing piece of the piezoresistive pressure sensor is normal, or represents that the resistance value of the pressure sensing piece of the piezoresistive pressure sensor is abnormal. When any one of the output first detection result and the output second detection result represents that the circuit is abnormal, corresponding measures can be taken to process so that the piezoresistive pressure sensor works normally, thereby improving the signal accuracy of the piezoresistive pressure sensor and increasing the product qualification rate.
In this embodiment, the at least one voltage output terminal is at least one of the first voltage output terminal and the second voltage output terminal.
In the above, the detection method of the detection circuit of the piezoresistive pressure sensor provided in this embodiment is based on the detection circuit of the piezoresistive pressure sensor, and whether the piezoresistive pressure sensor is connected correctly and whether the resistance of the pressure sensing element of the piezoresistive pressure sensor is problematic is determined by different data of the detection circuit when the detection circuit is turned on and off, so as to assist production and improve the signal accuracy and the product yield of the piezoresistive pressure sensor.
The present embodiment also provides an electronic device, referring to fig. 7, including:
and a processing chip 730, configured to receive the voltage signal output by the piezoresistive pressure sensor, and process the voltage signal output by the piezoresistive pressure sensor.
The piezoresistive pressure sensor 710, the piezoresistive pressure sensor adopts a wheatstone bridge circuit, the piezoresistive pressure sensor includes a first voltage output end and a second voltage output end, the first voltage output end is connected with a first voltage input pin of the processing chip, and the second voltage output end is connected with a second voltage input pin of the processing chip;
the detection circuit 720 is a detection circuit provided in the above embodiment, for example, the detection circuit in fig. 2 and 5.
The control end of the switch of the detection unit in the detection circuit 720 is connected with the control signal output pin of the processing chip, and different switches correspond to different control signal output pins, so that when one detection unit enters a detection state, other detection units are in a non-detection state that the switch is disconnected, and each pressure sensing piece of the piezoresistive pressure sensor is detected one by one.
The detection circuit 720 includes at least one detection unit of a first detection unit, a second detection unit, a third detection unit, and a fourth detection unit; each detection unit comprises a current source and a switch connected in series with the current source, and the control end of the switch is connected with the processing chip; the first detection unit is used for being connected between the first voltage output end and the first grounding end; the second detection unit is used for being connected between the first power end and the first voltage output end; the third detection unit is used for being connected between the second voltage output end and the first grounding end; the fourth detection unit is a detection unit used for being connected between the first power end and the first voltage output end.
The detection circuit 720 further includes a reference current circuit, and the current source of each detection unit in the detection circuit is a mirror current source corresponding to the reference current circuit. The reference current circuit comprises an operational amplifier, a first PMOS tube, a second PMOS tube, a first NMOS tube, a second NMOS tube and a resistor; the first input end of the operational amplifier is a reference power supply input end, the second input end of the operational amplifier is connected with the source electrode of the first NMOS tube, the output end of the operational amplifier is connected with the grid electrode of the first NMOS tube, and the resistor is connected between the second input end and the first grounding end; the source electrode of the first PMOS tube and the source electrode of the second PMOS tube are connected with a first power supply end, the drain electrode of the first PMOS tube is connected with the drain electrode of the first NMOS tube, and the grid electrode of the first PMOS tube is connected with the drain electrode of the first PMOS tube and the grid electrode of the second PMOS tube; the drain electrode of the second PMOS tube is connected with the drain electrode of the second NMOS tube, the source electrode of the second NMOS tube is connected with the first grounding end, and the grid electrode of the second NMOS tube is connected with the drain electrode of the second NMOS tube; the current sources of the second detection unit and the fourth detection unit correspond to the mirror current sources of the first PMOS tube; the current sources of the first detection unit and the third detection unit are mirror image current sources corresponding to the second NMOS tube. The specific structure and connection relation of the detection circuit are described in the detection circuit of the piezoresistive pressure sensor, and are not described herein.
It should be noted that, the processing chip of the present embodiment is configured to implement a detection method of the detection circuit shown in fig. 6 under the control of the computer program stored in the memory. The memory may be a memory of the processing chip or an external memory of the non-processing chip.
The embodiment of the application also provides a readable storage medium, on which a program or an instruction is stored, which when executed by a processing chip, implements each process of the detection method embodiment of the detection circuit, and can achieve the same technical effects, and in order to avoid repetition, the description is omitted here.
The processing chip is the processing chip in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium such as a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a magnetic disk or an optical disk, and the like.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element. Furthermore, it should be noted that the scope of the methods and apparatus in the embodiments of the present application is not limited to performing the functions in the order shown or discussed, but may also include performing the functions in a substantially simultaneous manner or in an opposite order depending on the functions involved, e.g., the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.
From the above description of the embodiments, it will be clear to those skilled in the art that the above-described embodiment method may be implemented by means of software plus a necessary general hardware platform, but of course may also be implemented by means of hardware, but in many cases the former is a preferred embodiment. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art in the form of a software product stored in a storage medium (e.g. ROM/RAM, magnetic disk, optical disk) comprising instructions for causing a terminal (which may be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to perform the method according to the embodiments of the present application.
The embodiments of the present application have been described above with reference to the accompanying drawings, but the present application is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present application and the scope of the claims, which are to be protected by the present application.
Claims (9)
1. The detection circuit of the piezoresistive pressure sensor is characterized in that the piezoresistive pressure sensor adopts a Wheatstone bridge circuit, and comprises a first voltage output end and a second voltage output end, wherein the first voltage output end is connected with a first voltage input pin of a processing chip, and the second voltage output end is connected with a second voltage input pin of the processing chip;
the detection circuit comprises at least one detection unit of a first detection unit, a second detection unit, a third detection unit and a fourth detection unit; each detection unit comprises a current source and a switch connected with the current source in series, and the control end of the switch is connected with the processing chip;
The first detection unit is used for being connected between the first voltage output end and a first grounding end; the second detection unit is a detection unit used for being connected between a first power end and the first voltage output end; the third detection unit is a detection unit used for being connected between the second voltage output end and the first grounding end; the fourth detection unit is a detection unit used for being connected between the first power end and the first voltage output end;
The detection circuit further comprises a reference current circuit, and the current source of each detection unit in the detection circuit is a mirror current source corresponding to the reference current circuit.
2. The detection circuit of claim 1, comprising at least two of the first detection unit, the second detection unit, the third detection unit, and the fourth detection unit, wherein the at least two detection units comprise a detection unit connected to the first voltage output and a detection unit connected to the second voltage output.
3. The detection circuit of claim 1, wherein the detection circuit comprises the first detection unit, the second detection unit, the third detection unit, and the fourth detection unit.
4. The detection circuit of claim 1, wherein the switch is a switching tube.
5. The detection circuit according to any one of claims 1 to 4, wherein current values of current sources of the detection cells in the detection circuit are equal.
6. The detection circuit of claim 1, wherein the reference current circuit comprises an operational amplifier, a first PMOS transistor, a second PMOS transistor, a first NMOS transistor, a second NMOS transistor, and a resistor;
The first input end of the operational amplifier is a reference power supply input end, the second input end of the operational amplifier is connected with the source electrode of the first NMOS tube, the output end of the operational amplifier is connected with the grid electrode of the first NMOS tube, and the resistor is connected between the second input end and the first grounding end; the source electrode of the first PMOS tube and the source electrode of the second PMOS tube are connected with the first power supply end, the drain electrode of the first PMOS tube is connected with the drain electrode of the first NMOS tube, and the grid electrode of the first PMOS tube is connected with the drain electrode of the first PMOS tube and the grid electrode of the second PMOS tube; the drain electrode of the second PMOS tube is connected with the drain electrode of the second NMOS tube, the source electrode of the second NMOS tube is connected with the first grounding end, and the grid electrode of the second NMOS tube is connected with the drain electrode of the second NMOS tube;
The current sources of the second detection unit and the fourth detection unit correspond to the mirror current sources of the first PMOS tube;
the current sources of the first detection unit and the third detection unit are mirror current sources corresponding to the second NMOS tube.
7. A detection method based on the detection circuit according to any one of claims 1 to 6, characterized by comprising:
a detection unit for determining the detection state of the detection circuit; under the condition that one detection unit enters a detection state, the other detection units are in a non-detection state that a switch is disconnected;
For a detection unit entering a detection state, firstly controlling a switch of the detection unit to be turned off, and then controlling the switch of the detection unit to be turned on; the detection unit and a pressure sensing piece on a bridge arm of the piezoresistive pressure sensor are connected in series between a first power end and a first grounding end;
under the condition that the switch is disconnected, respectively acquiring a first voltage value of a first voltage output end and a second voltage value of a second voltage output end of the piezoresistive pressure sensor, and calculating a first voltage difference value between the second voltage value and the first voltage value;
Under the condition that the switch is conducted, a third voltage value of the first voltage output end and a fourth voltage value of the second voltage output end are respectively obtained, and a second voltage difference value between the fourth voltage value and the third voltage value is calculated;
Comparing the first voltage difference with the second voltage difference to obtain a comparison result;
According to the comparison result, the current value of the current source of the detection unit and the standard resistance value of the pressure sensing piece, a first detection result of whether the connection between at least one voltage output end and the processing chip is wrong or not and a second detection result of whether the actual resistance value of the pressure sensing piece is consistent with the standard resistance value or not are obtained and output; wherein the at least one voltage output terminal is at least one of the first voltage output terminal and the second voltage output terminal.
8. An electronic device, comprising:
A processing chip;
The piezoresistive pressure sensor adopts a Wheatstone bridge circuit, and comprises a first voltage output end and a second voltage output end, wherein the first voltage output end is connected with a first voltage input pin of the processing chip, and the second voltage output end is connected with a second voltage input pin of the processing chip; and
The detection circuit is as claimed in any one of claims 1 to 6, wherein a control end of a switch of the detection unit in the detection circuit is connected with a control signal output pin of the processing chip, and different switches correspond to different control signal output pins.
9. The electronic device of claim 8, wherein the processing chip is configured to implement the detection method of claim 8 under control of a computer program stored in a memory.
Priority Applications (2)
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| CN202111090431.8A CN113865757B (en) | 2021-09-16 | 2021-09-16 | Detection circuit, detection method and electronic equipment of piezoresistive pressure sensor |
| PCT/CN2022/119292 WO2023041030A1 (en) | 2021-09-16 | 2022-09-16 | Detection circuit and detection method for piezoresistive pressure sensor, and electronic device |
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| CN202111090431.8A CN113865757B (en) | 2021-09-16 | 2021-09-16 | Detection circuit, detection method and electronic equipment of piezoresistive pressure sensor |
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| CN112764566B (en) * | 2019-11-01 | 2024-07-02 | 福州京东方光电科技有限公司 | Control method and device of touch screen and electronic equipment |
| CN113865757B (en) * | 2021-09-16 | 2024-07-09 | 歌尔微电子股份有限公司 | Detection circuit, detection method and electronic equipment of piezoresistive pressure sensor |
| CN115950470B (en) * | 2022-12-20 | 2024-04-19 | 陕西宝成航空仪表有限责任公司 | Sensor function self-checking circuit |
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| WO2023041030A1 (en) | 2023-03-23 |
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