Pressure measurement circuit, chip and electronic device

Abstract

Embodiments of the present application provide a pressure measurement circuit, a chip and an electronic device. The pressure measurement circuit comprises: a channel selection module, comprising: a first channel configured to receive a pressure voltage signal output by a pressure sensor; and a second channel configured to receive an auxiliary voltage signal output by an auxiliary detection module, wherein the auxiliary voltage signal matches a misadjustment voltage of the pressure sensor; the channel selection module is configured to perform channel selection in the first channel and the second channel according to a control signal; and a signal conditioning module connected to the channel selection module and configured to determine a pressure value corresponding to the pressure according to a difference between the pressure voltage signal and the auxiliary voltage signal. The embodiments of the present application can be used to offset the error caused by stress on pressure detection, and improve the accuracy of pressure detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic circuits, in particular to a pressure measurement circuit, a chip and an electronic device. BACKGROUND

[0002] The pressure sensor generates a pressure voltage signal based on the pressing force, and the pressure corresponding digital signal can be obtained by converting the pressure voltage signal, so as to realize the detection of the pressing force.

[0003] When there is a pressing force, the circuit board will be deformed, and the circuit on the circuit board for detecting the output signal of the pressure sensor is affected by stress, resulting in an error between the detected pressure value and the actual pressure value. SUMMARY

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

[0005] In a first aspect, the embodiments of the present application provide a pressure measurement circuit, comprising: a channel selection module, comprising: a first channel configured to receive a pressure voltage signal output by a pressure sensor; and a second channel configured to receive an auxiliary voltage signal output by an auxiliary detection module, wherein the auxiliary voltage signal matches a bias voltage of the pressure sensor; the channel selection module is configured to select a channel in the first channel and the second channel according to a control signal; and a signal conditioning module connected to the channel selection module and configured to determine a pressure value corresponding to pressure according to a difference between the pressure voltage signal and the auxiliary voltage signal. The auxiliary voltage output by the auxiliary detection module includes an auxiliary voltage signal matching the bias voltage of the pressure sensor, and the pressure voltage signal output by the pressure sensor includes a voltage corresponding to pressing and a bias voltage of the pressure sensor. Under the influence of stress, the signal detected by the signal conditioning module includes a measurement deviation caused by stress. By selecting the pressure voltage signal and the auxiliary voltage signal through the channel selection module, since the auxiliary voltage signal matches the bias voltage of the pressure sensor, and the signal conditioning module is subjected to basically the same stress when the first channel and the second channel are selected, the measurement deviation caused by stress is basically the same, so that the signal output by the auxiliary detection module can be used to offset the measurement deviation caused by stress, thereby improving the accuracy of pressure detection.

[0006] Optionally, the signal conditioning module comprises an analog-to-digital conversion unit configured to perform analog-to-digital conversion on the signal selected by the channel selection module.

[0007] Optionally, the signal conditioning module further comprises a programmable gain amplification unit connected between the channel selection module and the analog-to-digital conversion unit, configured to amplify the signal selected by the channel selection module; and the analog-to-digital conversion unit is configured to convert the signal amplified by the programmable gain amplification unit into a digital signal.

[0008] Optionally, the signal conditioning module further comprises a digital-to-analog conversion unit connected to the programmable gain amplification unit, configured to compensate for the offset voltage in the signal output by the programmable gain amplification unit.

[0009] Optionally, the channel selection module is configured to: in a first period, select the first channel to enable the signal conditioning module to convert the pressure voltage signal into a first digital signal; and in a second period, select the second channel to enable the signal conditioning module to convert the auxiliary voltage signal into a second digital signal; and the first period and the second period belong to the same pressure detection cycle.

[0010] Optionally, the signal conditioning module is configured to: determine the difference between the first digital signal and the second digital signal, and take the difference as the pressure value corresponding to the pressure.

[0011] Optionally, the pressure measurement circuit further comprises the auxiliary detection module.

[0012] Optionally, the auxiliary detection module comprises a first output end and a second output end, and the auxiliary voltage signal is a differential voltage signal between the first output end and the second output end.

[0013] Optionally, the auxiliary detection module comprises at least one electrical component whose electrical characteristics are not affected by stress changes.

[0014] Optionally, the auxiliary detection module comprises a voltage dividing resistor string, and at least one voltage dividing node of the voltage dividing resistor string is configured to output the auxiliary voltage signal.

[0015] Optionally, 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.

[0016] In a second aspect, an embodiment of the present application provides a pressure detection circuit, comprising: a pressure sensor configured to generate a pressure voltage signal based on a pressing force; and the pressure measurement circuit.

[0017] In a third aspect, an embodiment of the present application provides a chip, comprising the pressure measurement circuit.

[0018] In a fourth aspect, an embodiment of the present application provides an electronic device, comprising a device body, and the chip, the pressure measurement circuit, or the pressure detection circuit disposed on the device body.

[0019] In a fifth aspect, the embodiments of the present application provide a pressure detection method, comprising: for at least one pressure detection period: 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 matches a bias 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.

[0020] Optionally, the determining of the pressure value corresponding to the pressure detection period according to the first digital signal and the second digital signal comprises: determining a difference between the first digital signal and the second digital signal, and taking the difference as the pressure value corresponding to the pressure detection period.

[0021] The circuit for the pressure sensor, the chip and the electronic device provided by the embodiments of the present application can solve the problem that the circuit on the circuit board for detecting the output signal of the pressure sensor is affected by stress, resulting in an error between the detected pressure value and the actual pressure value, and have the effect of improving the accuracy of pressure detection.

[0022] These aspects or other aspects of the present application will be more apparent in the following description of the embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0024] Figure 1 A schematic block diagram of the pressure measurement circuit provided by the embodiments of the present application is shown.

[0025] Figure 2 Another schematic block diagram of the pressure measurement circuit provided by the embodiments of the present application is shown.

[0026] Figure 3 Still another schematic block diagram of the pressure measurement circuit provided by the embodiments of the present application is shown.

[0027] Figure 4 Still another schematic block diagram of the pressure measurement circuit provided by the embodiments of the present application is shown.

[0028] Figure 5 A circuit diagram of the auxiliary detection module provided by the embodiments of the present application is shown.

[0029] Figure 6A schematic block diagram of a pressure detection circuit provided by an embodiment of the present application is shown.

[0030] Figure 7 A flow chart of a pressure detection method provided by an embodiment of the present application is shown. DETAILED DESCRIPTION

[0031] Embodiments of the present application are described in detail below with reference to the accompanying drawings, in which the same or similar components have the same or similar designations and functions throughout the various figures and embodiments. The embodiments described below are exemplary only, and are not intended to limit the present application in any way.

[0032] In order to make the technical personnel in the art better understand the scheme of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0033] In the embodiments of the present application, at least one means one or more; and multiple means two or more than two. In the description of the present application, the terms "first", "second", "third" and the like are only used to distinguish the described purposes, and cannot be understood as indicating or implying relative importance, nor can it be understood as indicating or implying order.

[0034] In the description of the present application, the reference "an embodiment" or "some embodiments" and the like means that the specific features, structures or characteristics described in connection with the embodiment are included in one or more embodiments of the present application. Therefore, the terms "include", "contain", "have" and their variants in the present description mean "include but not limited to", unless otherwise specifically emphasized.

[0035] It should be noted that in the embodiments of the present application, the "and / or" description of the associated objects represents that there can be three relationships, for example, A and / or B can represent the existence of A alone, the existence of A and B together, and the existence of B alone.

[0036] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be direct or indirect connection between two electrical components. For example, A and B are connected, which can be direct connection between A and B, or indirect connection between A and B through one or more other electrical components.

[0037] The circuit for a pressure sensor provided in the present application can be applied in an electronic device, wherein the electronic device can include a computing unit and a memory. The computing unit can perform various appropriate actions and processes according to a computer program stored in the memory, for example, processing a digital signal corresponding to pressure.

[0038] Optionally, the electronic device can be, but is not limited to, a body weight scale, a body fat scale, a nutrition scale, an infrared electronic thermometer, a pulse oximeter, a human body composition analyzer, a mobile power supply, a wireless charger, a fast charger, a vehicle charger, an adapter, a display, a USB (Universal Serial Bus) docking station, a touch pen, a truly wireless earphone, a car central control screen, a car, a smart wearable device, a mobile terminal, and a smart home device. The smart wearable device includes, but is not limited to, a smart watch, a smart bracelet, a cervical vertebra massage instrument, a TWS (True Wireless Stereo) earphone, 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 sales terminal) machine. The smart home device includes, but is not limited to, a smart socket, a smart rice cooker, a smart sweeper, and a smart lamp.

[0039] The pressure sensor can generate a pressure voltage signal based on a pressing force. Conversion of the pressure voltage signal can obtain a digital signal corresponding to pressure, and realize detection of the pressing force. When there is a pressing force, the circuit board deforms, and the circuit on the circuit board for detecting the output signal of the pressure sensor is affected by stress, resulting in an error between the detected pressure value and the actual pressure value. In this document, pressure is applied from the outside to the circuit, especially external force acting on the pressure sensor, which is usually generated by pressing action. Stress refers to the internal force generated between parts of an object when the circuit such as a pressure sensor deforms due to external factors such as force.

[0040] The embodiment of the present application provides a pressure measurement circuit which at least reduces pressure measurement error to improve pressure detection accuracy.

[0041] In the embodiment of the present application, the pressure sensor is a device or apparatus that can sense a pressure signal and convert the pressure signal into an available output according to a certain rule. The pressure sensor usually includes a pressure sensitive element.

[0042] Figure 1 A schematic block diagram of the pressure measurement circuit provided by the embodiment of the present application is shown as Figure 1As shown, the circuit 100 can 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 select a channel between the first channel and the second channel according to a control signal. The signal conditioning module 12, connected to the channel selection module 11, is configured to determine a pressure value corresponding to the pressure according to a difference between the pressure voltage signal and the auxiliary voltage signal.

[0043] The auxiliary voltage signal output by the auxiliary detection module 22 includes an auxiliary voltage signal matching the offset voltage of the pressure sensor, and the pressure voltage signal output by the pressure sensor 21 includes a pressure corresponding voltage and the offset voltage of the pressure sensor 21. The signal detected by the signal conditioning module 12 includes a measurement deviation caused by the stress. The factors affecting 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 the stress 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 stress in addition to the auxiliary voltage signal. 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 11 selects the second channel, the first stress voltage is substantially the same as the second stress voltage, and the auxiliary voltage signal matches the offset voltage of the pressure sensor, so that the measurement result of the signal output by the auxiliary detection module 22 can be used to offset the effect of the stress to improve the accuracy of pressure detection.

[0044] As an embodiment, the amplitude of the auxiliary voltage signal matches the amplitude of the offset voltage 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 amplitude of the offset voltage of the pressure sensor. It should be understood that the term "equal" herein does not mean absolute equality in the mathematical sense. The closer the auxiliary voltage signal to the offset voltage of the pressure sensor, the better the auxiliary voltage signal is to offset the error caused by the stress.

[0045] In some embodiments, at least one pressure detection cycle includes a first period and a second period. The channel selection module 11 is configured to: select a first channel during the first period, causing the signal conditioning module 12 to convert the pressure voltage signal into a first digital signal; and select a second channel during the second period, causing the signal conditioning module 12 to convert the auxiliary voltage signal into a second digital signal. In this embodiment, the difference in stress between the first and second periods can be ignored during the stress application process. In some cases, both the first and second periods occur during the pressure application process; in other cases, the first period occurs during the pressure application process, and the second period occurs after the pressure application, with the stress from the pressure still acting during the second period.

[0046] The signal conditioning module 12 is configured to determine a pressure value corresponding to the pressure based on the first digital signal and the second digital signal. In one embodiment, the signal conditioning module 12 is configured to: determine the difference between the first digital signal and the second digital signal, and use this difference as the pressure value corresponding to the pressure.

[0047] The possible implementations of the signal conditioning module 12 are described below.

[0048] In some implementations, such as Figure 2 As shown, the signal conditioning module 12 may include an analog-to-digital converter (ADC) unit 121. The output of the channel selection module 11 is connected to the ADC unit 121, and the ADC unit 121 is configured to perform analog-to-digital conversion on the signal output of the channel selection module 11. For example, during a first period, the channel selection module 11 selects a first channel, and the output of the channel selection module 11 outputs a pressure voltage signal. The ADC unit 121 converts the pressure voltage signal into a first digital signal. During a second period, the channel selection module 11 selects a second channel, and the output of the channel selection module 11 outputs an auxiliary voltage signal. The ADC unit 121 converts the auxiliary voltage signal into a second digital signal.

[0049] In some implementations, such as Figure 3As shown, the signal conditioning module 12 may include an analog-to-digital converter (ADC) 121 and a programmable gain amplifier (PGA) 122. The PGA 122 amplifies the input signal, and the ADC 121 converts the amplified input signal into a digital signal. For example, the PGA 122 amplifies the pressure-voltage signal during a first period, and the ADC 121 converts the amplified pressure-voltage signal into a digital signal (i.e., a first digital signal); the PGA 122 amplifies the auxiliary voltage signal during a second period, and the ADC 121 converts the amplified auxiliary voltage signal into a digital signal (i.e., a second digital signal).

[0050] In some embodiments, the signal conditioning module 12 includes an analog-to-digital converter 121 with offset compensation and a programmable gain amplifier 122. For example... Figure 4 As shown, offset compensation can be performed by a digital-to-analog converter (DAC) 123, which can be input with a code value to control the generation of a voltage or current signal to calibrate the output voltage of the PGA, thereby compensating for the offset voltage in the output signal of the programmable gain amplifier (PGA) 122 and canceling out the offset portion in the output voltage of the PGA 122. The analog-to-digital converter (ADC) 121 converts the voltage signal output by the PGA 122 into a digital signal for subsequent digital circuit processing. Offset voltage includes voltage caused by component mismatch. Generally, sensor outputs contain offset voltage, and component mismatch within the PGA 122 itself may also generate offset voltage. The combination of these two factors, amplified by the PGA, exacerbates the offset voltage; therefore, offset compensation is performed by the DAC 123.

[0051] As one example, the digital-to-analog converter 123 can output a current that can generate a voltage across a resistor inside the programmable gain amplifier 122, thereby canceling the offset voltage. As another example, the digital-to-analog converter 123 can output a voltage that can be injected into or extracted from the output of the programmable gain amplifier 122 to cancel the offset.

[0052] In some implementations, the pressure voltage signal output by the pressure sensor is a differential voltage signal to improve signal accuracy and eliminate common error interference. As one implementation, the auxiliary detection module 22 includes a first output terminal and a second output terminal. The aforementioned auxiliary voltage signal is the differential voltage signal between the first and second output terminals, that is, the difference between the voltage signals at the first and second output terminals.

[0053] In some embodiments, the pressure measurement circuit 100 may include the auxiliary detection module 22 described above.

[0054] In some embodiments, the auxiliary detection module 22 includes at least one electrical component whose electrical characteristics are unaffected by stress changes, so that the auxiliary voltage signal output by the auxiliary detection module 22 is unaffected by stress changes.

[0055] In one implementation, the auxiliary detection module 22 may include a voltage divider resistor string, at least one voltage divider node of which is used to output the auxiliary voltage signal. Optionally, the voltage divider resistor string includes at least two resistor modules. The voltage divider resistor string includes one or more output terminals. The difference between the voltage signals at any two output terminals of the voltage divider resistor string can be used as the aforementioned auxiliary voltage signal.

[0056] Taking the auxiliary detection module 22 as a differential output as an example, the voltage divider resistor string includes at least three resistors connected in series, and there are at least two voltage divider nodes between the at least three resistors connected in series. The second channel is connected to two of the voltage divider nodes. The auxiliary voltage signal is the voltage difference between the two voltage divider nodes connected to the second channel.

[0057] As an example, such as Figure 5 As shown, the auxiliary detection module 22 includes resistors R1, R2, and R3. R1, R2, and R3 are connected in series. One end of R1 is connected to the reference voltage Vref, and the other end is connected in series with R2. One end of R3 is connected in series with R2, and the other end is grounded (Gnd). One output terminal for outputting the auxiliary voltage signal is located between R1 and R2, and the output voltage signal is inp1. The other output terminal for outputting the auxiliary voltage signal is located between R2 and 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 differential form of the auxiliary voltage signal. The theoretical value of the difference between inp1 and inn1 matches the offset voltage of the pressure sensor mentioned above.

[0058] In one implementation, the channel selection module 11 may include a data multiplexer (MUX). As an example, the channel selection module 11 may include a 2-to-1 data multiplexer, where one channel receives the aforementioned auxiliary voltage signal and the other channel receives the aforementioned pressure voltage signal.

[0059] As an implementation, the channel selection circuit 11 is a multiplexer (MUX). The multiplexer includes two first inputs and two second inputs; the two first inputs are connected to the two outputs of the pressure sensor 21 respectively to receive the pressure voltage signal output by the pressure sensor 21, and the voltage difference between the two first inputs is the pressure voltage signal; the two second inputs are connected to the two outputs of the auxiliary detection module 22 respectively to receive the auxiliary voltage signal output by the auxiliary detection module 22, and the voltage difference between the two second inputs is the auxiliary voltage signal; and an output of the multiplexer is connected to an input of the signal conditioning module 12 to selectively transmit the signal received by the two first inputs to the signal conditioning module 12 or transmit the signal received by the two second inputs to the signal conditioning module 12.

[0060] The embodiment of the present application provides a pressure detection circuit. The pressure detection circuit can offset the interference signal caused by stress and improve the accuracy of signal detection.

[0061] Figure 6 A schematic block diagram of the pressure detection circuit provided by the embodiment of the present application is shown in FIG. 6. Figure 6 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.

[0062] 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 perform channel selection according to a control signal, wherein the channel selection module 63 includes a first channel configured to receive the pressure voltage signal output by the pressure sensor 61 and a second channel configured to receive the auxiliary voltage signal output by the auxiliary detection module 62.

[0063] The signal conditioning module 64 is configured to determine a pressure value corresponding to the pressure according to the pressure voltage signal and the auxiliary voltage signal. The signal conditioning module 64 can refer to the foregoing description. As an example, Figure 6 The signal conditioning module 64 shown in FIG. 6 includes a PGA 641, a DAC 642, and an ADC 643. The PGA 641 is connected to the output of the channel selection module 63 to amplify the signal output by the channel selection module 63. The DAC 642 is connected to the PGA 641 to generate a voltage signal or a current signal to compensate for the offset voltage in the signal output by the PGA 641. The ADC 643 is configured to perform analog-to-digital conversion on the signal output by the PGA 641.

[0064] As an example, the channel selection module 63 is configured to select a first channel during a first period and a second channel during a second period. The signal conditioning module 64 converts the pressure-voltage signal during the first period to obtain a first digital signal; converts the auxiliary voltage signal during the second period to obtain a second digital signal; and determines a third digital signal corresponding to the pressure based on the first and second digital signals. For example, the difference between the first and second digital signals is determined and used as the pressure value corresponding to the pressure.

[0065] In some implementations, such as Figure 6 As shown, the auxiliary detection module 62 may include resistors R1, R2, and R3. R1, R2, and R3 are connected in series. One end of R1 is connected to the reference voltage Vref1, and the other end is connected in series with R2. One end of R3 is connected in series with R2, and the other end is grounded. One output terminal is located between R1 and R2, outputting a voltage signal inp1; another output terminal is located between R2 and R3, outputting a voltage signal inn1. The signal output by the auxiliary detection module 62 is the difference between inp1 and inn1, which is the differential auxiliary voltage signal. The theoretical value of the difference between inp1 and inn1 matches the offset voltage of the pressure sensor 61. Figure 6 As shown, the pressure sensor 61 may include resistors R4, R5, R6, and R7. R4, R5, R6, and R7 are connected end-to-end to form a Wheatstone bridge. The voltage divider node between R4 and R5 is connected to the reference voltage Vref2, the voltage divider node between R6 and R7 is grounded (gnd), the voltage divider node between R4 and R7 outputs voltage inn2, and the voltage divider node between R4 and R7 outputs voltage inp2. The pressure voltage signal output by the pressure sensor 61 is the difference between inp2 and inn2. As an example, the auxiliary detection module 62 and the pressure sensor 61 can be connected to the same power supply; for example, Vref1 and Vref2 can be the same reference voltage. Alternatively, Vref1 and Vref2 can be replaced with the power supply voltage VDD or the operating voltage VS output by the chip's voltage regulator module.

[0066] In this embodiment, at least a portion of the circuit modules of the pressure detection circuit 600 may be integrated circuits.

[0067] In one implementation, the integrated circuit internally includes a channel selection module 63 and a signal conditioning module 64; the integrated circuit externally may include a pressure sensor 61 and an auxiliary detection module 62.

[0068] In another implementation, the integrated circuit internally includes: an auxiliary detection module 62, a channel selection module 63, and a signal conditioning module 64; the integrated circuit externally may include: a pressure sensor 61.

[0069] As yet another embodiment, the integrated circuit internally comprises: a signal conditioning module 64; and externally comprises: a pressure sensor 61, an auxiliary detection module 62, and a channel selection module 63.

[0070] The principles of an embodiment of the present application are described below in conjunction with Figure 6 The principles of an embodiment of the present application are described below in conjunction with

[0071] The output signal of the pressure sensor 61 can be denoted as Vin+Vsensor_offset, where Vin is the effective signal due to the pressing operation (Vin=inp2-inn2) and Vsensor_offset is the offset voltage of the pressure sensor 61.

[0072] When the channel selection module 63 selects the pressure sensor 61, the output voltage of the PGA 641 (i.e. the input voltage of the ADC) is as follows:

[0073] Without stress, Vo1=(Vin+Vsensor_offset-Vdac_calibration)*Gain;

[0074] With stress, Vo1=(Vin+Vsensor_offset-Vdac_calibration+Vstress)*Gain;

[0075] where Gain is the gain (amplification) of the PGA 641; Vdac_calibration is the output voltage of the DAC 642, which is used to offset the offset voltage Vsensor_offset, so Vdac_calibration is set to be approximately equal to Vsensor_offset, and thus, without stress, Vo1=Vin*Gain; and with stress, Vo1=(Vin+Vstress)*Gain. Vstress is the interference signal due to stress, which is amplified by Gain after passing through the PGA 641. When there is no stress, the output voltage of the PGA 641 after compensation by the DAC 642 can ideally correspond to the effective signal Vin*Gain; and when there is stress, the output voltage of the PGA 641 increases by the interference signal Vstress*Gain, resulting in inaccurate measurement results.

[0076] When the channel selection module selects the auxiliary detection module 63, the output voltage of the PGA 641 is as follows:

[0077] Without stress, Vo2=(V 辅助 -Vdac_calibration_ 辅助 )*Gain;

[0078] When there is stress, Vo2=(V 辅助 -Vdac_calibration_ 辅助 +Vstress_ 辅助 Gain;

[0079] Among them, V 辅助 It is the voltage output by the auxiliary detection module, V 辅助 =inp1-inn1;Vdac_calibration_ 辅助 This is the output voltage of the DAC 642. (Vstress_) 辅助 It is an interference signal generated by stress when the channel selection module 63 selects the auxiliary detection module.

[0080] Since the output voltage of the DAC 642 remains constant within the same period, i.e., Vdac_calibration = Vdac_calibration_ 辅助 V 辅助 and Vdac_calibration_ 辅助 Both are matched to the offset voltage Vsensor_offset; therefore, Vo2≈0 under no stress and Vo2≈Vstress_offset under stress. 辅助 *Gain.

[0081] When V 辅助 When Vsensor_offset is approximately equal to Vsensor_offset, under the same stress, the interference signal Vstress generated by the stress is similar to Vstress. 辅助 They are approximately equal. Then, by sequentially selecting pressure sensor 61 and auxiliary detection module 62, Vo1 and Vo2 are obtained successively. Vo1 is then subtracted from Vo2 to obtain Vo1-Vo2 = Vin*Gain. The value of Vo1-Vo2 is used as the result of pressure detection, thus canceling out the interference caused by stress.

[0082] This application provides a pressure detection method. This pressure detection method can be implemented by the pressure detection circuit described above. In this method, at least one pressure detection cycle includes a first period and a second period.

[0083] Figure 7 A flowchart of the pressure detection method provided in an embodiment of this application is shown, as follows: Figure 7 As shown, the pressure detection method includes steps S701 to S703.

[0084] In step S701, during the first period, the pressure voltage signal output by the pressure sensor is converted to obtain a first digital signal.

[0085] In step S702, a second digital signal is obtained by converting the auxiliary voltage signal output by the auxiliary detection module in the second period, wherein the auxiliary voltage signal matches the offset voltage of the pressure sensor.

[0086] In step S703, a pressure value corresponding to the pressure detection period is determined according to the first digital signal and the second digital signal.

[0087] As an implementation form, a difference between the first digital signal and the second digital signal is determined, and the difference is taken as the pressure value corresponding to the pressure detection period.

[0088] The method of the embodiment of the present application, in the first period, the signal converted further includes a first measurement deviation (referred to as a first stress voltage) caused by stress; in the second period, the signal converted further includes a second measurement deviation (referred to as a second stress voltage) caused by stress, in addition to the auxiliary voltage signal. Since the circuit board is subjected to basically the same stress in the first period and the second period, the first stress voltage is basically the same as the second stress voltage, and the auxiliary voltage signal matches the offset voltage of the pressure sensor, so the conversion results in the first period and the second period can be used to offset the influence of stress, so as to improve the pressure detection accuracy.

[0089] The chip includes the circuit. The chip can be, but is not limited to, a SOC (System on Chip) chip, a SIP (system in package) chip. The auxiliary voltage output by the auxiliary detection module includes an auxiliary voltage signal matched with the offset voltage of the pressure sensor, and the pressure voltage signal output by the pressure sensor includes a corresponding voltage pressed and the offset voltage of the pressure sensor. The signal detected by the signal conditioning module includes a measurement deviation caused by stress. The pressure voltage signal and the auxiliary voltage signal are selected by the channel selection module. When the channel selection module selects the first channel, the signal detected by the signal conditioning module includes a first measurement deviation (referred to as a first stress voltage) caused by stress 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 (referred to as a second stress voltage) caused by stress in addition to the auxiliary voltage signal. Because the signal conditioning module is subjected to basically 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 is basically the same as the second stress voltage, 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 to offset the influence of stress, thereby improving the accuracy of pressure detection.

[0090] The electronic device includes a device body and a chip, a circuit or a pressure detection circuit as described above arranged in the device body. The electronic device can be, but is not limited to, a body scale, a body fat scale, a nutrition scale, an infrared electronic thermometer, a pulse oximeter, a human body composition analyzer, a mobile power supply, a wireless charger, a fast charger, a vehicle charger, an adapter, a display, a USB (Universal Serial Bus) docking station, a touch pen, a truly wireless earphone, a car control panel, a car, a smart wearable device, a mobile terminal and a smart home device. The smart wearable device includes, but is not limited to, a smart watch, a smart bracelet and a cervical vertebra massage instrument. The mobile terminal includes, but is not limited to, a smart phone, a notebook computer, a tablet computer and a POS (point of sales terminal) machine. The smart home device includes, but is not limited to, a smart socket, a smart rice cooker, a smart sweeper and a smart lamp.

[0091] The electronic device outputs an auxiliary voltage signal matching the offset voltage of the pressure sensor through an auxiliary detection module. The auxiliary voltage output by the auxiliary detection module contains the auxiliary voltage signal matching the offset voltage of the pressure sensor, and the pressure voltage signal output by the pressure sensor contains the corresponding voltage pressed and the offset voltage of the pressure sensor. The signal detected by the signal conditioning module is affected by stress, and includes a measurement deviation caused by stress. 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 includes a first measurement deviation (referred to as a first stress voltage) caused by stress in addition to the pressure voltage signal; when the channel selection module selects a second channel, the signal detected by the signal conditioning module includes a second measurement deviation (referred to as a second stress voltage) caused by stress in addition to the auxiliary voltage signal. Since 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 is substantially the same as the second stress voltage, and the auxiliary voltage signal matches the offset voltage of the pressure sensor, so that the measurement result of the signal output by the auxiliary detection module can be used to offset the influence of stress to improve the accuracy of pressure detection.

[0092] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the preferred embodiment of the present application has been disclosed as above, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the equivalent embodiments of the above disclosed technical content without departing from the scope of the technical solution of the present application. Any modification, equivalent change and modification of the above embodiments made according to the technical essence of the present application, without departing from the technical solution content of the present application, still belongs to the scope of the technical solution of the present application.

Claims

1. A pressure measurement circuit, characterized by The circuit comprises: A channel selection module comprising: A first channel for receiving a pressure voltage signal output by a pressure sensor; A second channel for receiving an auxiliary voltage signal output by an auxiliary detection module, wherein the auxiliary voltage signal matches a bias voltage of the pressure sensor, and the auxiliary voltage signal contains a disturbance signal affected by stress; The channel selection module is configured to select a channel between the first channel and the second channel according to a control signal; A signal conditioning module connected to the channel selection module and configured to determine a pressure value corresponding to pressure according to a difference between the pressure voltage signal and the auxiliary voltage signal; The channel selection module is configured to select the first channel during a first period to make the signal conditioning module convert the pressure voltage signal into a first digital signal, and select the second channel during a second period to make the signal conditioning module convert the auxiliary voltage signal into a second digital signal, wherein the first period and the second period belong to a same pressure detection cycle.

2. The pressure measurement circuit of claim 1, wherein, The signal conditioning module comprises: An analog-to-digital conversion unit configured to perform analog-to-digital conversion on a signal selected by the channel selection module.

3. The pressure measurement circuit of claim 2, wherein, The signal conditioning module further comprises: A programmable gain amplification unit connected between the channel selection module and the analog-to-digital conversion unit and configured to amplify the signal selected by the channel selection module; 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: A digital-to-analog conversion unit connected to the programmable gain amplification unit and configured to compensate for a bias voltage in a signal output by the programmable gain amplification unit.

5. The pressure measurement circuit of claim 1, wherein, The signal conditioning module is configured to determine a difference between the first digital signal and the second digital signal and take the difference as a pressure value corresponding to pressure.

6. The pressure measurement circuit of claim 1, wherein, The auxiliary detection module is further included. 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.

7. The pressure measurement circuit of claim 1 or 6, wherein, The auxiliary detection module comprises at least one electrical component whose electrical characteristics change under stress.

8. The pressure measurement circuit of claim 1 or 6, wherein, The auxiliary detection module comprises a voltage dividing resistor string, and at least one voltage dividing node of the voltage dividing resistor string is used to output the auxiliary voltage signal.

9. The pressure measurement circuit of claim 1 or 6, wherein, The amplitude of the auxiliary voltage signal matches the amplitude of the bias voltage of the pressure sensor, and the common-mode voltage of the auxiliary voltage signal matches the common-mode voltage of the pressure voltage signal.

10. The pressure measurement circuit of claim 1, wherein, A pressure sensor for generating a pressure voltage signal based on pressing; 11. A pressure detection circuit, characterized by comprising: The pressure measurement circuit according to any one of claims 1 to 10. The pressure measurement circuit according to any one of claims 1 to 10. The device comprises a device body and a chip according to claim 12, a circuit according to any one of claims 1 to 10, or a pressure detection circuit according to claim 11, which are arranged on the device body.

12. A chip, characterized by The method comprises:

13. An electronic device, comprising: For at least one pressure detection cycle:

14. A pressure detection method characterized by, ​ ​ In a first period, a pressure voltage signal output by the pressure sensor is converted to obtain a first digital signal; In a second period, an auxiliary voltage signal output by an auxiliary detection module is converted to obtain a second digital signal, wherein the auxiliary voltage signal matches a misadjustment voltage of the pressure sensor, and the auxiliary voltage signal contains an interference signal affected by stress; A pressure value corresponding to the pressure detection period is determined according to a difference between the first digital signal and the second digital signal.

15. The pressure detection method according to claim 14, wherein The determination of the pressure value corresponding to the pressure detection period according to the difference between the first digital signal and the second digital signal comprises: A difference between the first digital signal and the second digital signal is determined, and the difference is taken as the pressure value corresponding to the pressure detection period.

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