CN115950570A - Pressure measurement circuit, chip and electronic equipment - Google Patents

Abstract

The embodiment of the application provides a pressure measurement circuit, a chip and electronic equipment. Wherein, this pressure measurement circuit includes: a channel selection module comprising: the first channel is used for receiving a pressure voltage signal output by the pressure sensor; the second channel is used for receiving an auxiliary voltage signal output by the auxiliary detection module, wherein the auxiliary voltage signal is matched with the offset voltage of the pressure sensor; the channel selection module is configured to: selecting a channel from the first channel and the second channel according to the control signal; and the signal conditioning module is connected with the channel selection module and is configured to determine a pressure value corresponding to the pressure according to the difference value of the pressure voltage signal and the auxiliary voltage signal. By adopting the embodiment of the application, the method and the device can be used for offsetting the error caused by the stress to the pressure detection and improving the accuracy of the pressure detection.

Description

Pressure measurement circuit, chip and electronic equipment

Technical Field

The application relates to the technical field of electronic circuits, in particular to a pressure measurement circuit, a chip and electronic equipment.

Background

The pressure sensor generates a pressure voltage signal based on the pressing acting force, the pressure voltage signal is converted to obtain a digital signal corresponding to the pressure, and the pressing acting force is detected.

When pressing the effort, the circuit board can take place deformation, and the circuit that is used for carrying out the output signal to pressure sensor on the circuit board detects receives stress influence, leads to detecting to have the error between the pressure value that obtains and the actual pressure value.

Disclosure of Invention

In view of the above problems, embodiments of the present application provide a pressure measurement circuit, a chip and an electronic device to solve the above technical problems.

In a first aspect, an embodiment of the present application provides a pressure measurement circuit, including: a channel selection module comprising: the first channel is used for receiving a pressure voltage signal output by the pressure sensor; the second channel is used for receiving an auxiliary voltage signal output by the auxiliary detection module, wherein the auxiliary voltage signal is matched with the offset voltage of the pressure sensor; the channel selection module is configured to: selecting a channel from the first channel and the second channel according to the control signal; and the signal conditioning module is connected with the channel selection module and is configured to determine a pressure value corresponding to the pressure according to the difference value of the pressure voltage signal and the auxiliary voltage signal. The auxiliary voltage output by the auxiliary detection module comprises an auxiliary voltage signal matched with the offset voltage of the pressure sensor, and the pressure voltage signal output by the pressure sensor comprises a voltage corresponding to pressing and the offset voltage of the pressure sensor. Is affected by stress, and the signal detected by the signal conditioning module comprises a measurement deviation caused by the stress influence. The pressure voltage signal and the auxiliary voltage signal are selected through the channel selection module, the auxiliary voltage signal is matched with offset voltage of the pressure sensor, and the signal conditioning module is subjected to basically the same stress when the first channel is selected and the second channel is selected, so that measurement deviation caused by stress influence is basically the same, and the signal output by the auxiliary detection module can be used for offsetting the measurement deviation caused by the stress, so that the pressure detection accuracy is improved.

Optionally, a signal conditioning module comprising: and the analog-to-digital conversion unit is configured to perform analog-to-digital conversion on the signal gated by the channel selection module.

Optionally, the signal conditioning module further includes: the programmable gain amplification unit is connected between the channel selection module and the analog-to-digital conversion unit and is configured to amplify the signal gated by the channel selection module; wherein the analog-to-digital conversion unit is configured to perform analog-to-digital conversion on the signal amplified by the programmable gain amplification unit.

Optionally, the signal conditioning module further includes: and the digital-to-analog conversion unit is connected with the programmable gain amplification unit and is configured to compensate offset voltage in an output signal of the programmable gain amplification unit.

Optionally, a channel selection module configured to: in a first period, selecting the first channel to enable the signal conditioning module to convert the pressure voltage signal into a first digital signal; in a second period, selecting a second channel to enable the signal conditioning module to convert the auxiliary voltage signal into a second digital signal; wherein the first period and the second period belong to the same pressure detection cycle.

Optionally, a signal conditioning module configured to: a difference between the first digital signal and the second digital signal is determined, and the difference is taken as a pressure value corresponding to the pressure.

Optionally, the pressure measurement circuit further comprises: the auxiliary detection module.

Optionally, the auxiliary detection module includes a first output terminal and a second output terminal, and the auxiliary voltage signal is a differential voltage signal between the first output terminal and the second output terminal.

Optionally, the auxiliary detection module comprises: at least one electrical component having an electrical characteristic that is not subject to stress variations.

Optionally, the auxiliary detection module comprises: and at least one voltage division node of the voltage division resistor string is used for outputting the auxiliary voltage signal.

Optionally, the auxiliary voltage signal has an amplitude matching an offset voltage amplitude of the pressure sensor, and the common mode voltage of the auxiliary voltage signal matches a common mode voltage of the pressure voltage signal.

In a second aspect, an embodiment of the present application provides a pressure detection circuit, including: a pressure sensor for generating a pressure voltage signal based on the pressing; and the pressure measurement circuit described above.

In a third aspect, an embodiment of the present application provides a chip including the pressure measurement circuit described above.

In a fourth aspect, an embodiment of the present application provides an electronic device, which includes a device main body, and the chip, the pressure measurement circuit, or the pressure detection circuit that are provided in the device main body.

In a fifth aspect, an embodiment of the present application provides a pressure detection method, where the method includes: for at least one pressure detection cycle: in a first period, converting a pressure voltage signal output by a pressure sensor to obtain a first digital signal; in a second period, converting an auxiliary voltage signal output by the auxiliary detection module to obtain a second digital signal, wherein the auxiliary voltage signal is matched with the offset voltage of the pressure sensor; and determining a pressure value corresponding to the pressure detection period according to the first digital signal and the second digital signal.

Optionally, determining a pressure value corresponding to the pressure detection period according to the first digital signal and the second digital signal includes: and determining a difference value between the first digital signal and the second digital signal, and taking the difference value as a pressure value corresponding to the pressure detection period.

The circuit, the chip and the electronic equipment for the pressure sensor can solve the problem that a circuit used for detecting the output signal of the pressure sensor on a circuit board is affected by stress, so that an error exists between a detected pressure value and an actual pressure value, and the effect of improving the accuracy of pressure detection is achieved.

These and other aspects of the present application will be more readily apparent from the following description of the embodiments.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 shows a schematic block diagram of a pressure measurement circuit provided by an embodiment of the present application.

Fig. 2 shows another schematic block diagram of a pressure measurement circuit provided by an embodiment of the present application.

Fig. 3 shows another schematic block diagram of a pressure measurement circuit provided by an embodiment of the present application.

Fig. 4 shows a further schematic block diagram of a pressure measurement circuit provided by an embodiment of the present application.

Fig. 5 shows a circuit diagram of an auxiliary detection module provided in an embodiment of the present application.

Fig. 6 shows a schematic block diagram of a pressure detection circuit provided in an embodiment of the present application.

Fig. 7 shows a flowchart of a pressure detection method provided in an embodiment of the present application.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

In order to make the technical solutions of the present application better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments obtained by a person skilled in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.

In the embodiments of the present application, at least one means one or more; plural means two or more. In the description of the present application, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance, nor order.

Reference throughout this specification to "one embodiment" or "some embodiments," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, the terms "including," "comprising," "having," and variations thereof in this specification mean "including, but not limited to," unless expressly specified otherwise.

It should be noted that in the embodiment of the present application, "and/or" describes an association relationship of an associated object, and indicates that three relationships may exist, for example, a and/or B may indicate: a exists alone, A and B exist simultaneously, and B exists alone.

It is to be noted that "connected" in the embodiments of the present application may be understood as an electrical connection, and the connection of two electrical components may be a direct or indirect connection between the two electrical components. For example, a and B may be connected directly, or indirectly through one or more other electrical components.

The circuit for a pressure sensor provided by the invention can be applied to electronic equipment, wherein the electronic equipment can comprise a computing unit and a memory. A computing unit that can perform various appropriate actions and processes, for example, processing digital signals corresponding to pressure, according to computer programs stored in the memory.

Alternatively, the electronic device may be, but is not limited to, a weight scale, a body fat scale, a nutrition scale, an infrared electronic thermometer, a pulse oximeter, a body composition analyzer, a mobile power supply, a wireless charger, a fast charger, an in-vehicle charger, an adapter, a display, a USB (Universal Serial Bus) docking station, a stylus, a true wireless headset, a control screen in an automobile, an intelligent wearable device, a mobile terminal, and an intelligent home device. The smart wearable device includes, but is not limited to, a smart watch, a smart bracelet, a cervical vertebra massager, a TWS (True Wireless Stereo) headset, and the like. The mobile terminal includes, but is not limited to, a smart phone, a notebook computer, a tablet computer, and a POS (point of sale) machine. The intelligent household equipment comprises but is not limited to an intelligent socket, an intelligent electric cooker, an intelligent sweeper and an intelligent lamp.

The pressure sensor can generate a pressure voltage signal based on the pressing force. The pressure voltage signal is converted to obtain a digital signal corresponding to the pressure, so that the detection of the pressing acting force is realized. When the pressing acting force exists, the circuit board deforms, and a circuit used for detecting the output signal of the pressure sensor on the circuit board is influenced by stress, so that an error exists between a detected pressure value and an actual pressure value. In this context, the external force applied to the circuit from the outside, in particular acting on the pressure sensor, is generally generated by a pressing action. Stress is an internal force that generates interaction between parts in an object when a circuit such as a pressure sensor is deformed due to an external force such as a force.

The embodiment of the application provides a pressure measurement circuit, and the circuit at least reduces pressure measurement error to improve pressure detection accuracy.

In the embodiment of the present application, the pressure sensor is a device or apparatus capable of sensing a pressure signal and converting the pressure signal into a usable output electrical signal according to a certain rule. Pressure sensors typically include a pressure sensitive element.

Fig. 1 shows a schematic block diagram of a pressure measurement circuit provided in an embodiment of the present application, and as shown in fig. 1, the circuit 100 may include: a channel selection module 11 and a signal conditioning module 12. The channel selection module 11 includes: a first channel for receiving a pressure voltage signal output by the pressure sensor 21; and a second channel for receiving an auxiliary voltage signal output by the auxiliary detection module 22, wherein the auxiliary voltage signal matches the offset voltage of the pressure sensor 21. The channel selection module 11 is configured to perform channel selection among the first channel and the second channel according to a control signal. And the signal conditioning module 12 is connected with the channel selection module 11 and is configured to determine a pressure value corresponding to the pressure according to the difference value of the pressure voltage signal and the auxiliary voltage signal.

The auxiliary voltage signal output by the auxiliary detection module 22 includes an auxiliary voltage signal matched with the offset voltage of the pressure sensor, and the pressure voltage signal output by the pressure sensor 21 includes a voltage corresponding to the pressing and the offset voltage of the pressure sensor 21. Is subject to stress and the signal detected by the signal conditioning module 12 includes measurement deviations caused by the stress. The factors influencing the measurement deviation include the magnitude of the pressing force, the physical characteristics of the circuit board, and the electrical characteristics of the circuit elements. The pressure voltage signal and the auxiliary voltage signal are selected by the channel selection module 11. When the channel selection module 11 selects the first channel, the signal detected by the signal conditioning module 12 includes a first measurement deviation (referred to as a first stress voltage) caused by stress influence in addition to the pressure voltage signal; when the channel selection module selects the second channel, the signal detected by the signal conditioning module 12 includes a second measurement deviation (referred to as a second stress voltage) caused by the influence of stress in addition to the auxiliary voltage signal, and since the signal conditioning module 12 is subjected to substantially the same stress when the channel selection module 11 selects the first channel and when the channel selection module selects the second channel, the first stress voltage and the second stress voltage are substantially the same, and the auxiliary voltage signal is matched with the offset voltage of the pressure sensor, the measurement result of the signal output by the auxiliary detection module 22 can be used for offsetting the influence caused by stress, so as to improve the pressure detection accuracy.

As an embodiment, the amplitude of the auxiliary voltage signal matches the offset voltage amplitude of the pressure sensor, and the common mode voltage of the auxiliary voltage signal matches the common mode voltage of the pressure voltage signal. As an example, the amplitude of the auxiliary voltage signal is equal to the offset voltage amplitude of the pressure sensor. It should be understood that the term "equal" herein is not absolute equal in the mathematical sense. The closer the auxiliary voltage signal is to the offset voltage of the pressure sensor, the more beneficial the error caused by the offset stress can be offset.

In some embodiments, the at least one pressure detection cycle includes a first period and a second period. A channel selection module 11 configured to: in the first period, a first channel is selected, so that the signal conditioning module 12 converts the pressure voltage signal into a first digital signal; in the second period, the second channel is selected, so that the signal conditioning module 12 converts the auxiliary voltage signal into a second digital signal. In the process of applying stress during the first period and the second period, the difference between the stress during the first period and the stress during the second period can be ignored in this embodiment. In some cases, both the first period and the second period are during the application of pressure; in other cases, the first period is during the application of pressure, the second period is after the application of pressure, and the stress resulting from the pressure is still applied during the second period.

The signal conditioning module 12 is configured to determine a pressure value corresponding to the pressure from the first digital signal and the second digital signal. As an embodiment, the signal conditioning module 12 is configured to: and determining a difference value between the first digital signal and the second digital signal, and taking the difference value as a pressure value corresponding to the pressure.

A possible embodiment of the signal conditioning module 12 is described below.

In some embodiments, as shown in fig. 2, the signal conditioning module 12 may include an analog-to-digital conversion unit 121. The output end of the channel selection module 11 is connected to the analog-to-digital conversion unit 121, and the analog-to-digital conversion unit 121 is configured to perform analog-to-digital conversion on the signal at the output end of the channel selection module 11. For example, in a first period, the channel selection module 11 selects a first channel, the output end of the channel selection module 11 outputs a pressure voltage signal, and the analog-to-digital conversion unit 121 converts the pressure voltage signal into a first digital signal; in the second period, the channel selection module 11 selects a second channel, the output end of the channel selection module 11 outputs an auxiliary voltage signal, and the analog-to-digital conversion unit 121 converts the auxiliary voltage signal into a second digital signal.

In some embodiments, as shown in fig. 3, the signal conditioning module 12 may include an analog-to-digital conversion unit 121 and a Programmable Gain Amplifier (PGA) 122. The programmable gain amplifying unit 122 is configured to amplify an input signal, and the analog-to-digital converting unit 121 is configured to convert the input signal amplified by the PGA into a digital signal. For example, the programmable gain amplifying unit 122 amplifies the pressure voltage signal in the first period, and the analog-to-digital converting unit 121 converts the amplified pressure voltage signal into a digital signal (i.e., a first digital signal); the programmable gain amplifying unit 122 amplifies the auxiliary voltage signal in the second period, and the analog-to-digital converting unit 121 converts the amplified auxiliary voltage signal into a digital signal (i.e., a second digital signal).

In some embodiments, the signal conditioning module 12 includes an analog-to-digital conversion unit 121 with offset compensation and a programmable gain amplification unit 122. As shown in fig. 4, the offset compensation can be performed by a digital-to-analog conversion unit (DAC) 123, which can input a code value to control it to generate a voltage signal or a current signal to calibrate the output voltage of the PGA, so as to compensate the offset voltage in the output signal of the programmable gain amplification unit 122, thereby partially canceling the offset in the output voltage of the programmable gain amplification unit 122. The analog-to-digital conversion unit 121 can convert the voltage signal output from the programmable gain amplification unit 122 into a digital signal for digital circuit processing at a subsequent stage. Offset voltage includes because the voltage that components and parts mismatch and lead to, has offset voltage in the output of general sensor, and programmable gain amplification unit 122 self components and parts mismatch also can produce offset voltage, and both superposes and amplify back offset voltage through PGA and aggravate again, consequently carry out offset compensation by digital analog conversion unit 123.

As an example, the digital-to-analog conversion unit 123 may output a current that may generate a voltage across a resistor inside the programmable gain amplification unit 122, thereby canceling out the offset voltage. As another example, the digital-to-analog conversion unit 123 may output a voltage, which is injected into the output terminal of the programmable gain amplification unit 122 or extracted from the output terminal of the programmable gain amplification unit 122 to cancel the offset.

In some embodiments, the pressure voltage signal output by the pressure sensor is a differential voltage signal, so as to improve the signal accuracy and remove common error interference. In one embodiment, the auxiliary detection module 22 includes a first output terminal and a second output terminal, and the auxiliary voltage signal is a differential voltage signal between the first output terminal and the second output terminal, that is, a difference between a voltage signal of the first output terminal and a voltage signal of the second output terminal.

In some embodiments, the pressure measurement circuit 100 may include the auxiliary detection module 22 described above.

In some embodiments, the auxiliary detection module 22 includes: at least one electrical characteristic is not affected by stress variation, so that the auxiliary voltage signal output by the auxiliary detection module 22 is not affected by stress variation.

As an embodiment, the auxiliary detection module 22 may include: and at least one voltage division node of the voltage division resistor string is used for outputting the auxiliary voltage signal. Optionally, the voltage-dividing resistor string includes at least two resistor modules. The voltage-dividing resistor string includes one or more output terminals. The difference between the voltage signals of any two output ends of the voltage dividing resistor string can be used as the auxiliary voltage signal.

Taking the auxiliary detection module 22 as an example of differential output, the voltage-dividing resistor string includes at least three resistors connected in series, at least two voltage-dividing nodes are provided between the at least three resistors connected in series, and the second channel is connected to two of the voltage-dividing nodes; the auxiliary voltage signal is a voltage difference between two voltage division nodes connected with the second channel.

As an example, as shown in fig. 5, the auxiliary detection module 22 includes R1, R2, and R3. R1, R2 and R3 are connected in series, one end of R1 is connected with a reference voltage Vref, and the other end of R1 is connected with R2 in series; one end of R3 is connected with R2 in series, and the other end is grounded (Gnd). An output end for outputting the auxiliary voltage signal is positioned between the R1 and the R2, and the output voltage signal is inp1; the other output end for outputting the auxiliary voltage signal is positioned between the R2 and the R3, and the output voltage signal is inn1. The auxiliary voltage signal output by the auxiliary detection module 22 is the difference between inp1 and inn1, i.e. the auxiliary voltage signal in differential form. The theoretical value of the difference between inp1 and inn1 matches the offset voltage of the pressure sensor described above.

The channel selection module 11 may include a data selector (MUX) as an embodiment. As an example, the channel selection module 11 may include a 1-out-of-2 data selector, one channel receiving the auxiliary voltage signal and another channel receiving the pressure voltage signal.

As an embodiment, the channel selection circuit 11 is a Multiplexer (MUX). The multiplexer comprises two first input ends and two second input ends; the two first input ends are correspondingly connected to the two output ends of the pressure sensor 21 to receive the pressure voltage signal output by the pressure sensor 21, and the voltage difference between the two first input ends is the pressure voltage signal; the two second input ends are correspondingly connected to the two output ends of the auxiliary detection module 22 to receive the auxiliary voltage signal output by the auxiliary detection module 22, and a voltage difference between the two second input ends is the auxiliary voltage signal; the output of the multiplexer is connected to the input of the signal conditioning module 12, so as to selectively transmit the signals received by the two first inputs to the signal conditioning module 12, or transmit the signals received by the two second inputs to the signal conditioning module 12.

The embodiment of the application provides a pressure detection circuit. The pressure detection circuit can offset interference signals caused by stress, and improves the accuracy of signal detection.

Fig. 6 shows a schematic block diagram of a pressure detection circuit provided in an embodiment of the present application, and as shown in fig. 6, the pressure detection circuit 600 includes: a pressure sensor 61, an auxiliary detection module 62, a channel selection module 63, and a signal conditioning module 64.

The pressure sensor 61 is configured to output a pressure voltage signal based on the pressing. The auxiliary detection module 62 is configured to output an auxiliary voltage signal matching the offset voltage of the pressure sensor 61. The channel selection module 63 is configured to select a channel according to the control signal, wherein the channel selection module 63 includes: a first channel for receiving a pressure voltage signal output by the pressure sensor 61; and a second channel for receiving the auxiliary voltage signal output by the auxiliary detection module 62.

The signal conditioning module 64 is configured to determine a pressure value corresponding to the pressure from the pressure voltage signal and the auxiliary voltage signal. The signal conditioning module 64 can be seen in the description herein above. As an example, the analog-to-digital conversion module 64 shown in fig. 6 includes: PGA641, DAC 642, and ADC 643. The PGA641 is connected to the output terminal of the channel selection module 63, and is configured to amplify the signal output by the channel selection module 63. DAC 642 is connected to PGA641 for generating a voltage signal or a current signal to compensate for an offset voltage in the output signal of PGA 641. The ADC 643 is configured to analog-to-digital convert the PGA641 output signal.

As an example, the channel selection module 63 is configured to: selecting a first channel during a first period; during a second period, a second channel is selected. The signal conditioning module 64 converts the pressure voltage signal in the first period to obtain a first digital signal; converting the auxiliary voltage signal in the second period to obtain a second digital signal; and determining a third digital signal corresponding to the pressure according to the first digital signal and the second digital signal. For example, a difference between the first digital signal and the second digital signal is determined, and the difference is taken as a pressure value corresponding to the pressure.

In some embodiments, as shown in fig. 6, the auxiliary detection module 62 may include: including R1, R2 and R3. R1, R2 and R3 are connected in series, one end of R1 is connected with a reference voltage Vref1, and the other end of R1 is connected with R2 in series; one end of R3 is connected with R2 in series, and the other end is grounded. An output end is positioned between the R1 and the R2, and the output voltage signal is inp1; the other output end is positioned between the R2 and the R3, and the output voltage signal is inn1. The signal output by the auxiliary detection module 22 is the difference between inp1 and inn1, which is the auxiliary voltage signal in differential form. The theoretical value of the difference between inp1 and inn1 matches the offset voltage of the pressure sensor 61 described above. As shown in fig. 6, the pressure sensor 61 may include: r4, R5, R6 and R7. R4, R5, R6 and R7 are sequentially connected end to form a Wheatstone bridge. The voltage dividing node between R4 and R5 is connected to the reference voltage Vref2, the voltage dividing node between R6 and R7 is grounded gnd, the voltage dividing node between R4 and R7 outputs the voltage inn2, and the voltage dividing node between R4 and R7 outputs the voltage inp2. The pressure voltage signal output by the pressure sensor 61 is the difference between inp2 and inn 2. As an example, the auxiliary detection module 62 and the pressure sensor 61 may be connected to the same power supply, e.g., vref1 and Vref2 may be the same reference voltage; alternatively, vref1 and Vref2 may be replaced with the power supply voltage VDD or the operating voltage VS output by the chip regulator module.

In this embodiment, at least a part of the circuit blocks of the pressure detection circuit 600 may be an integrated circuit.

As an embodiment, the integrated circuit internally includes: a channel selection module 63 and a signal conditioning module 64; the integrated circuit exterior may include: a pressure sensor 61 and an auxiliary detection module 62.

As another embodiment, the integrated circuit includes internally: an auxiliary detection module 62, a channel selection module 63 and a signal conditioning module 64; the integrated circuit exterior may include: a pressure sensor 61.

As still another embodiment, the integrated circuit includes internally: a signal conditioning module 64; the integrated circuit exterior may include: a pressure sensor 61, an auxiliary detection module 62 and a channel selection module 63.

The principles of one embodiment of the application are described below in conjunction with fig. 6.

The output signal of the pressure sensor 61 can be expressed as Vin + Vsensor _ offset, i.e., the sum of Vin and Vsensor _ offset, where Vin is the valid signal (Vin = inp2-inn 2) generated due to the pressing operation, and Vsensor _ offset is the offset voltage of the pressure sensor 61.

When the channel selection module 63 gates the pressure sensor 61, the output voltage of the PGA641 (i.e., the input voltage of the ADC) is as follows:

vo1= (Vin + Vsensor _ offset-Vdac _ calibration) = Gain without stress;

vo1= (Vin + Vsensor _ offset-Vdac _ calibration + Vstress) × Gain when stress exists;

where Gain is the Gain (amplification) of PGA 641; vdac _ calibration is a voltage output by the DAC 642 and is used for canceling the offset voltage Vsensor _ offset, so Vdac _ calibration ≈ Vsensor _ offset is preset, and then Vo1= Vin × Gain in the absence of stress; vo1= (Vin + Vstress) × Gain when there is stress. Vstress is an interference signal generated by stress, and is amplified by Gain after passing through PGA 641. When there is no stress effect, ideally the output voltage of the PGA641 compensated by the DAC 642 may correspond to the valid signal Vin × Gain; when there is stress influence, the output voltage of the PGA641 increases by the disturbance signal Vstress Gain, resulting in inaccurate measurement results.

When the channel selection module gates the auxiliary detection module 63, the output voltage of the PGA641 is as follows:

vo2= (V) in the absence of stress _{Assistance of} -Vdac_calibration_ _{Assistance of} )*Gain；

Vo2= (V) in case of stress _{Assistance of} -Vdac_calibration_ _{Assistance of} +Vstress_ _{Assistance of} )*Gain；

Wherein, V _{Assistance of} Is the voltage, V, output by the auxiliary detection module _{Assistance of} ＝inp1-inn1；Vdac_calibration_ _{Assistance of} Is the voltage output by DAC 642. Vstress_ _{Assistance of} Is a disturbance signal generated by stress influence when the channel selection module 63 gates the auxiliary detection module.

Since the voltage of the output of DAC 642 is not changed during the same period, i.e., vdac _ calibration = Vdac _ calibration \ u _{Assistance of} ，V _{Assistance of} And Vdac _ calibration \ _{Assistance of} Are all matched with the offset voltage Vsensor _ offset, therefore, vo2 is approximately equal to 0 in the absence of stress; in the presence of stress, vo2 is about Vstress _{Assistance of} *Gain。

When V is _{Assistance of} When the stress is approximately equal to Vsensor _ offset, interference signals Vstress and Vstress generated under the influence of stress under the same stress action _{Assistance of} Approximately equal. Then, the pressure sensor 61 and the auxiliary detection module 62 are sequentially gated to obtain Vo1 and Vo2, vo1 is subtracted from Vo2 to obtain Vo1-Vo2= Vin × Gain, and the value of Vo1-Vo2 is used as the pressure detection result, i.e., the interference caused by stress is cancelled.

The embodiment of the application provides a pressure detection method. The pressure detection method can be realized by the pressure detection circuit. In the method, the at least one pressure sensing cycle includes a first period and a second period.

Fig. 7 shows a flowchart of a pressure detection method provided in an embodiment of the present application, and as shown in fig. 7, the pressure detection method includes: step S701 to step S703.

In step S701, in the first period, the pressure voltage signal output by the pressure sensor is converted to obtain a first digital signal.

Step S702, during a second period, converting the auxiliary voltage signal output by the auxiliary detection module to obtain a second digital signal, wherein the auxiliary voltage signal is matched with the offset voltage of the pressure sensor.

Step S703, determining a pressure value corresponding to the pressure detection period according to the first digital signal and the second digital signal.

In one embodiment, a difference between the first digital signal and the second digital signal is determined, and the difference is used as a pressure value corresponding to the pressure detection period.

In the method of the embodiment of the application, in the first period, besides the pressure voltage signal, the signal to be converted also includes a first measurement deviation (called as a first stress voltage) caused by stress influence; in the second period, the converted signal includes a second measurement deviation (called as a second stress voltage) caused by stress influence in addition to the auxiliary voltage signal, because the circuit board is subjected to basically the same stress in the first period and the second period, the first stress voltage and the second stress voltage are basically the same, and the auxiliary voltage signal is matched with the offset voltage of the pressure sensor, so that the conversion result in the first period and the second period can be used for offsetting the influence caused by the stress, and the pressure detection accuracy is improved.

The embodiment of the application also provides a chip, and the chip comprises the circuit. An Integrated Circuit (IC) is also called a Chip, and the Chip may be, but is not limited to, an SOC (System on Chip) Chip or an SIP (System in package) Chip. The auxiliary voltage output by the auxiliary detection module comprises an auxiliary voltage signal matched with the offset voltage of the pressure sensor, and the pressure voltage signal output by the pressure sensor comprises a voltage corresponding to pressing and the offset voltage of the pressure sensor. Is affected by stress, and the signal detected by the signal conditioning module comprises a measurement deviation caused by the stress influence. The pressure voltage signal and the auxiliary voltage signal are selected by a channel selection module. When the channel selection module selects a first channel, the signal detected by the signal conditioning module also comprises a first measurement deviation (called a first stress voltage) caused by stress influence besides the pressure voltage signal; when the channel selection module selects the second channel, the signal detected by the signal conditioning module includes a second measurement deviation (called as a second stress voltage) caused by the influence of stress besides the auxiliary voltage signal, and because the signal conditioning module is subjected to substantially the same stress when the channel selection module selects the first channel and when the channel selection module selects the second channel, the first stress voltage and the second stress voltage are substantially the same, and the auxiliary voltage signal is matched with the offset voltage of the pressure sensor, so that the measurement result of the signal output by the auxiliary detection module can be used for offsetting the influence caused by stress, thereby improving the pressure detection accuracy.

The embodiment of the application also provides electronic equipment, which comprises an equipment main body, and the chip, the circuit or the pressure detection circuit which are arranged in the equipment main body. The electronic device may be, but is not limited to, a weight scale, a body fat scale, a nutrition scale, an infrared electronic thermometer, a pulse oximeter, a body composition analyzer, a mobile power supply, a wireless charger, a quick charger, a vehicle charger, an adapter, a display, a USB (Universal Serial Bus) docking station, a stylus pen, a true wireless headset, a screen in an automobile, an intelligent wearable device, a mobile terminal, and an intelligent home device. The intelligent wearable device comprises but is not limited to an intelligent watch, an intelligent bracelet and a cervical vertebra massager. Mobile terminals include, but are not limited to, smart phones, laptops, tablets, point of sale (POS) machines. The intelligent household equipment comprises but is not limited to an intelligent socket, an intelligent electric cooker, an intelligent sweeper and an intelligent lamp.

The electronic equipment outputs an auxiliary voltage signal matched with the offset voltage of the pressure sensor through the auxiliary detection module. The auxiliary voltage output by the auxiliary detection module comprises an auxiliary voltage signal matched with the offset voltage of the pressure sensor, and the pressure voltage signal output by the pressure sensor comprises a voltage corresponding to pressing and the offset voltage of the pressure sensor. Is affected by stress, and the signal detected by the signal conditioning module comprises a measurement deviation caused by the stress influence. The pressure voltage signal and the auxiliary voltage signal are selected by a channel selection module. When the channel selection module selects a first channel, the signal detected by the signal conditioning module comprises a first measurement deviation (called as a first stress voltage) caused by stress influence in addition to the pressure voltage signal; when the channel selection module selects the second channel, the signal detected by the signal conditioning module includes a second measurement deviation (called as a second stress voltage) caused by the influence of stress besides the auxiliary voltage signal, and because the signal conditioning module is subjected to substantially the same stress when the channel selection module selects the first channel and when the channel selection module selects the second channel, the first stress voltage and the second stress voltage are substantially the same, and the auxiliary voltage signal is matched with the offset voltage of the pressure sensor, so that the measurement result of the signal output by the auxiliary detection module can be used for offsetting the influence caused by stress, thereby improving the pressure detection accuracy.

Although the present application has been described with reference to the preferred embodiments, it is to be understood that the present application is not limited to the disclosed embodiments, but rather, the present application is intended to cover various modifications, equivalents and alternatives falling within the spirit and scope of the present application.

Claims (16)

1. A pressure measurement circuit, the circuit comprising:

a channel selection module comprising:

the first channel is used for receiving a pressure voltage signal output by the pressure sensor;

the second channel is used for receiving an auxiliary voltage signal output by an auxiliary detection module, wherein the auxiliary voltage signal is matched with the offset voltage of the pressure sensor;

the channel selection module is configured to: selecting a channel from the first channel and the second channel according to a control signal;

and the signal conditioning module is connected with the channel selection module and is configured to determine a pressure value corresponding to the pressure according to the difference value of the pressure voltage signal and the auxiliary voltage signal.

2. The pressure measurement circuit of claim 1, wherein the signal conditioning module comprises:

and the analog-to-digital conversion unit is configured to perform analog-to-digital conversion on the signal gated by the channel selection module.

3. The pressure measurement circuit of claim 2, wherein the signal conditioning module further comprises:

the programmable gain amplification unit is connected between the channel selection module and the analog-to-digital conversion unit and is configured to amplify the signal gated by the channel selection module;

wherein the analog-to-digital conversion unit is configured to perform analog-to-digital conversion on the signal amplified by the programmable gain amplification unit.

4. The pressure measurement circuit of claim 3, wherein the signal conditioning module further comprises:

and the digital-to-analog conversion unit is connected with the programmable gain amplification unit and is configured to compensate offset voltage in an output signal of the programmable gain amplification unit.

5. The pressure measurement circuit of any of claims 1-4, wherein the channel selection module is configured to:

during a first period, selecting the first channel to cause the signal conditioning module to convert the pressure voltage signal to a first digital signal;

during a second period, selecting the second channel to cause the signal conditioning module to convert the auxiliary voltage signal to a second digital signal;

wherein the first period and the second period belong to the same pressure detection cycle.

6. The pressure measurement circuit of claim 5, wherein the signal conditioning module is configured to: determining a difference between the first digital signal and the second digital signal as a pressure value corresponding to a pressure.

7. The pressure measurement circuit of claim 1, further comprising: the auxiliary detection module.

8. The pressure measurement circuit of claim 1 or 7, wherein the auxiliary detection module comprises a first output terminal and a second output terminal, and the auxiliary voltage signal is a differential voltage signal between the first output terminal and the second output terminal.

9. The pressure measurement circuit of claim 1 or 7, wherein the auxiliary detection module comprises: at least one electrical component having an electrical characteristic that is not subject to stress variations.

10. The pressure measurement circuit of claim 1 or 7, wherein the auxiliary detection module comprises: and at least one voltage division node of the voltage division resistor string is used for outputting the auxiliary voltage signal.

11. The pressure measurement circuit of claim 1 wherein the auxiliary voltage signal has an amplitude that matches an offset voltage amplitude of the pressure sensor and wherein a common mode voltage of the auxiliary voltage signal matches a common mode voltage of the pressure voltage signal.

12. A pressure detection circuit, comprising:

a pressure sensor for generating a pressure voltage signal based on the pressing;

a pressure measurement circuit according to any one of claims 1 to 11.

13. A chip comprising a pressure measurement circuit according to any one of claims 1 to 11.

14. An electronic device comprising a device body and the chip of claim 13, the circuit of any one of claims 1 to 11, or the pressure detection circuit of claim 12 provided in the device body.

15. A method of pressure detection, the method comprising:

for at least one pressure detection cycle:

in a first period, converting a pressure voltage signal output by a pressure sensor to obtain a first digital signal;

in a second period, converting an auxiliary voltage signal output by an auxiliary detection module to obtain a second digital signal, wherein the auxiliary voltage signal is matched with the offset voltage of the pressure sensor;

and determining a pressure value corresponding to the pressure detection period according to the first digital signal and the second digital signal.

16. The pressure detection method of claim 15, wherein the determining the pressure value corresponding to the pressure detection period from the first digital signal and the second digital signal comprises:

and determining a difference value between the first digital signal and the second digital signal, and taking the difference value as a pressure value corresponding to the pressure detection period.

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