WO2019174243A1 - 加速度传感器、电容检测电路及方法、加速度处理电路及方法、存储介质和电子设备 - Google Patents

加速度传感器、电容检测电路及方法、加速度处理电路及方法、存储介质和电子设备 Download PDF

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Publication number
WO2019174243A1
WO2019174243A1 PCT/CN2018/112178 CN2018112178W WO2019174243A1 WO 2019174243 A1 WO2019174243 A1 WO 2019174243A1 CN 2018112178 W CN2018112178 W CN 2018112178W WO 2019174243 A1 WO2019174243 A1 WO 2019174243A1
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Prior art keywords
capacitor
acceleration
switch
circuit
detection signal
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PCT/CN2018/112178
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English (en)
French (fr)
Inventor
刘友会
张娜
李朋
韩乐乐
祝政委
Original Assignee
京东方科技集团股份有限公司
合肥京东方光电科技有限公司
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Application filed by 京东方科技集团股份有限公司, 合肥京东方光电科技有限公司 filed Critical 京东方科技集团股份有限公司
Priority to US16/463,124 priority Critical patent/US11231440B2/en
Priority to EP18877296.6A priority patent/EP3770610B1/en
Priority to JP2020535550A priority patent/JP7256191B2/ja
Publication of WO2019174243A1 publication Critical patent/WO2019174243A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P1/00—Details of instruments
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/0891—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values with indication of predetermined acceleration values
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/125—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by capacitive pick-up
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
    • G01R27/2605—Measuring capacitance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P2015/0805—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration
    • G01P2015/0808—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration for defining in-plane movement of the mass, i.e. movement of the mass in the plane of the substrate
    • G01P2015/0811—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration for defining in-plane movement of the mass, i.e. movement of the mass in the plane of the substrate for one single degree of freedom of movement of the mass
    • G01P2015/0814—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration for defining in-plane movement of the mass, i.e. movement of the mass in the plane of the substrate for one single degree of freedom of movement of the mass for translational movement of the mass, e.g. shuttle type

Definitions

  • Embodiments of the present disclosure relate to an acceleration sensor, a capacitance detecting circuit and method, an acceleration processing circuit and method, a storage medium, and an electronic device.
  • Accelerometers are small in size, light in weight, convenient and flexible, and therefore have a wide range of applications in aircraft control, automotive safety and other fields.
  • Accelerometers are available in piezoresistive, piezoelectric, resonant, tunneling, and capacitive types.
  • the capacitive micro-acceleration sensor has the advantages of simple structure, stable output, small temperature drift and easy test integration, which is beneficial to mass production.
  • At least one embodiment of the present disclosure provides an acceleration sensor including: a base; a fixed electrode fixed to the base; and a mass movable relative to the fixed electrode; wherein the mass includes a conductive electrode
  • the conductive electrode and the fixed electrode are configured to form a capacitor, and a capacitance of the capacitor may be variable due to movement of the mass relative to the base.
  • the acceleration sensor further includes a dielectric layer between the conductive electrode and the fixed electrode.
  • the acceleration sensor further includes a cantilever beam on the base, the mass being coupled to the cantilever beam.
  • one end of the cantilever beam is coupled to the base, and the other end of the cantilever beam is coupled to the mass.
  • the cantilever beam comprises a spring.
  • the capacitance value of the capacitor is linear with the acceleration of the acceleration sensor.
  • the plurality of fixed electrodes are distributed, and a plurality of the fixed electrodes are distributed on the base.
  • a plurality of the fixed electrodes are arranged in parallel along a direction of movement of the mass relative to the base.
  • At least one embodiment of the present disclosure further provides a capacitance detecting circuit for monitoring a capacitance value of a capacitor of the acceleration sensor, including: a first capacitor and a detecting sub-circuit; wherein, the two ends of the first capacitor are respectively The fixed electrode of the acceleration sensor is electrically connected to the conductive electrode; and the detection sub-circuit is configured to convert a capacitance value of the first capacitor into a detection signal and output the detection signal.
  • the detection sub-circuit includes: a first switch, a second switch, a third switch, a second capacitor, a resistor, a generation sub-circuit, and a storage sub-circuit; wherein the first capacitor is configured to: Charging in response to the first switch being turned on; and discharging in response to the first switch being turned off, the second switch and the third switch being turned on, and charging the second capacitor;
  • the generating sub-circuit is configured to generate the detection signal according to a voltage of the second capacitor and a reference voltage, wherein when the voltage of the second capacitor is lower than the reference voltage, the generated detection signal is in a a level, when the voltage of the second capacitor is not lower than the reference voltage, the generated detection signal is at a second level; the second capacitor is configured to be in response to the detection signal a second level through which the discharge is discharged; and the storage sub-circuit is configured to buffer and output the detection signal.
  • the detecting sub-circuit further includes: a first inverter configured to invert and output a clock signal input to the clock signal terminal to a gate electrode of the first switch; and a second inversion And configured to invert the detection signal and output to a control pole of the third switch such that when the detection signal is at the first level, the third switch is turned on.
  • the detection sub-circuit further includes a fourth switch configured to be turned on in response to the detection signal being at the second level such that the second capacitor discharges through the resistor.
  • an input end of the first inverter is connected to the clock signal end, and an output end of the first inverter is connected to a control pole of the first switch;
  • An input end of the phase converter is connected to an output end of the generating sub-circuit, an output end of the second inverter is connected to a control pole of the third switch;
  • a first pole of the first switch and a first power source The terminal is connected to receive the input first voltage, the second pole of the first switch is connected to the first end of the first capacitor; the second end of the first capacitor is grounded;
  • the control pole of the second switch Connected to the clock signal terminal to receive the clock signal, a first pole of the second switch is coupled to a first end of the first capacitor, and a second pole of the second switch is coupled to the second capacitor a first end connection;
  • a first pole of the third switch is coupled to a second end of the second capacitor, and a second pole of the third switch is coupled to a second end of the first capacitor;
  • the generating subcircuit includes a comparator; a non-inverting input of the comparator is coupled to a first end of the second capacitor and a second end of the resistor, respectively An inverting input is coupled to the reference voltage terminal to receive the reference voltage, and an output of the comparator is coupled to an input of the second inverter.
  • the memory subcircuit includes a latch, an input of the latch being coupled to an output of the generating subcircuit.
  • the detection signal comprises a square wave signal, the number of pulses of the square wave signal being linear with the acceleration of the acceleration sensor.
  • At least one embodiment of the present disclosure also provides a capacitance detecting method for the capacitance detecting circuit, comprising: charging the first capacitor; repeating a charging and discharging operation until a charge release of the first capacitor is completed, wherein The charging and discharging operation includes: charging a second capacitor by discharging the first capacitor; and discharging the second capacitor; generating a location according to a voltage and a reference voltage of the second capacitor a detection signal, wherein when the voltage of the second capacitor is lower than the reference voltage, the generated detection signal is at a first level, when a voltage of the second capacitor is not lower than the reference voltage And generating the detection signal at a second level; and buffering and outputting the detection signal.
  • At least one embodiment of the present disclosure also provides an acceleration processing circuit including the capacitance detecting circuit, an acceleration calculating sub-circuit, and a processing sub-circuit; wherein the capacitance detecting circuit is configured to output the detection signal to the acceleration Calculating a sub-circuit; the acceleration calculation sub-circuit is configured to calculate an associated parameter value of the acceleration based on the detection signal; and the processing sub-circuit is configured to perform the associated parameter based on the associated parameter value of the acceleration Value the corresponding operation.
  • the associated parameter value is linear with the acceleration measured by the acceleration sensor.
  • the detection signal comprises a square wave signal, the associated parameter value comprising a number of pulses of the square wave signal.
  • the processing sub-circuit is configured to perform the operation when the number of pulses of the square wave signal is less than a set threshold.
  • the operations include: opening an airbag, dialing an alarm call, issuing a prompt message, or generating an alert signal.
  • At least one embodiment of the present disclosure also provides an acceleration processing method for the acceleration processing circuit, comprising: monitoring a capacitor in the acceleration sensor and converting a monitoring result into the detection signal; according to the detection signal, Calculating an associated parameter value of the acceleration; and performing an operation corresponding to the associated parameter value according to the associated parameter value of the acceleration.
  • the detection signal is a square wave signal; and calculating the associated parameter value of the acceleration according to the detection signal, comprising: counting the number of pulses of the square wave signal within a predetermined time period And performing, according to the associated parameter value of the acceleration, an operation corresponding to the associated parameter value of the acceleration, comprising: determining whether the number of pulses is less than a set threshold; and when the number of pulses is less than the When the threshold is set, the operation is performed.
  • At least one embodiment of the present disclosure also provides a storage medium having stored thereon computer instructions, wherein the computer instructions are executed by the processor to perform one or more of the acceleration processing methods described above.
  • At least one embodiment of the present disclosure also provides an electronic device comprising one or more processors configured to execute computer instructions to perform one or more of the above described acceleration processing methods.
  • FIG. 1 is a top plan view of an acceleration sensor according to some embodiments of the present disclosure
  • FIG. 2 is a cross-sectional view of the acceleration sensor taken along line A-A of FIG. 1 according to some embodiments of the present disclosure
  • FIG. 3A is a second top view of an acceleration sensor according to some embodiments of the present disclosure.
  • 3B is a cross-sectional view of the acceleration sensor taken along line B-B of FIG. 3A according to some embodiments of the present disclosure
  • FIG. 4 is a schematic diagram of displacement deformation of an acceleration sensor under acceleration by some embodiments of the present disclosure
  • FIG. 5A, FIG. 5B, FIG. 5C, and FIG. 5D are schematic diagrams showing the operation process of the acceleration sensor according to some embodiments of the present disclosure.
  • 6A is a structural diagram of a capacitor of an acceleration sensor when the acceleration is zero according to some embodiments of the present disclosure
  • 6B is a structural diagram of a capacitor of an acceleration sensor when the acceleration is greater than zero according to some embodiments of the present disclosure
  • FIG. 7A is a diagram showing relationship between an acceleration of an acceleration sensor and a capacitance value of a capacitor according to some embodiments of the present disclosure
  • 7B is a diagram showing a relationship between an acceleration of an interdigital acceleration sensor and a capacitance value of a capacitor
  • FIG. 8 is a structural block diagram of a capacitance detecting circuit according to some embodiments of the present disclosure.
  • FIG. 9A is a circuit diagram of a capacitance detecting circuit according to some embodiments of the present disclosure.
  • FIG. 9B is a second circuit diagram of a capacitance detecting circuit according to some embodiments of the present disclosure.
  • 10A is a diagram of a correspondence relationship between a charging and discharging process and a detection signal of a second capacitor according to some embodiments of the present disclosure
  • FIG. 10B is a second diagram of a correspondence relationship between a charging and discharging process and a detection signal of a second capacitor according to some embodiments of the present disclosure
  • FIG. 11A is a diagram showing relationship between an acceleration of an acceleration sensor and a number of high levels of a detection signal output according to some embodiments of the present disclosure
  • FIG. 11B is a second diagram showing the relationship between the acceleration of the acceleration sensor and the number of high levels of the detection signal output according to some embodiments of the present disclosure
  • Figure 11C is a graph showing the relationship between the acceleration of the interdigital acceleration sensor and the number of high levels of the detection signal output;
  • FIG. 12 is a flowchart of a method for detecting capacitance according to some embodiments of the present disclosure.
  • FIG. 13 is a block diagram showing the composition of an acceleration processing circuit according to some embodiments of the present disclosure.
  • FIG. 14 is a flowchart of an acceleration processing method according to some embodiments of the present disclosure.
  • FIG. 15 is a schematic diagram of a package circuit provided by some embodiments of the present disclosure.
  • the interdigital capacitive sensor is a commonly used microelectromechanical system (MEMS) acceleration sensor, and the interdigital MEMS acceleration sensor includes a movable detection mass on which a plurality of mutual components are disposed.
  • MEMS microelectromechanical system
  • Crossed finger structures to increase the sensitivity of the acceleration sensor.
  • the finger structure needs to occupy a large space, which is disadvantageous for miniaturization and integration of the device size.
  • the interdigital MEMS accelerometer since the distance between the capacitor and the interdigital finger is inversely proportional, the two are nonlinear, which is inconvenient for data calculation and processing.
  • the interdigital MEMS accelerometer is sensitive to the distance of the interdigital finger.
  • the calculation result may have a certain deviation, that is, different ambient temperatures, such as different In the seasons and in different regions, the interdigital MEMS accelerometers have different detection results for the same acceleration, and are greatly affected by temperature.
  • Embodiments of the present disclosure provide an acceleration sensor, a capacitance detecting circuit and method, an acceleration processing circuit and method, a storage medium, and an electronic device.
  • the acceleration sensor, the capacitance detecting circuit, and the acceleration processing circuit of the embodiments of the present disclosure can be applied in a scene in which acceleration detection is required.
  • the embodiment of the present disclosure converts the perceived acceleration into a capacitance value of the capacitor by the acceleration sensor, and the linear relationship between the capacitance value of the capacitor converted by the acceleration sensor of the embodiment of the present disclosure and the perceived acceleration is satisfied, thereby facilitating data calculation , processing and monitoring.
  • the acceleration sensor of the embodiment of the present disclosure has a small volume, is easy to integrate, and is not susceptible to temperature due to the absence of the interdigitated structure.
  • the embodiment of the present disclosure further converts the capacitance value of the capacitor sensed by the acceleration sensor into a detection signal (for example, a square wave signal) that is easy to detect and count by the capacitance detecting circuit, so that the capacitance value of the capacitor can be quickly and sensitively monitored.
  • the acceleration processing circuit of the embodiment of the present disclosure can also control a transportation tool such as an automobile to perform safety measures according to the detection signal outputted by the capacitance detecting circuit, thereby realizing protection of the personal safety of the driver and the passenger.
  • the acceleration sensor, the capacitance detecting circuit, and the acceleration processing circuit of the embodiments of the present disclosure can be applied to acceleration detection at a high speed collision of a vehicle.
  • the acceleration sensor provided by the embodiment of the present disclosure converts the acceleration of the vehicle into a capacitance value of the capacitor that satisfies a linear relationship with the acceleration, and then the capacitance detection circuit monitors the capacitance value of the capacitor, and converts the monitoring result into a convenient processing.
  • the detection signal (for example, a square wave signal) is finally determined by the acceleration processing circuit based on the detection signal to determine whether the vehicle has collided and the severity of the collision.
  • the safety protection measures are not activated (eg, the safety protection measures include the airbag).
  • the capacitance detecting circuit can transmit a detection signal (for example, a square wave signal) to the acceleration calculation sub-circuit and the processing sub-circuit, and then the acceleration calculation sub-circuit and the processing sub-circuit can quickly determine whether the vehicle has collided according to the detection signal and whether Safety measures should be activated (for example, starting the airbag).
  • a detection signal for example, a square wave signal
  • Safety measures should be activated (for example, starting the airbag).
  • the in-vehicle electronic control unit ECU sends a command to the igniter, and the igniter ignites in response to the command.
  • the gas generator then generates a large amount of gas (for example, nitrogen (N 2 )) and outputs N 2 to the airbag to protect the passenger's personal safety.
  • a large amount of gas for example, nitrogen (N 2 )
  • N 2 nitrogen
  • the acceleration sensor 100 of the embodiment of the present disclosure will be described below with reference to FIGS. 1-7B.
  • an embodiment of the present disclosure provides an acceleration sensor 100 , which may include a base 101 , a fixed electrode 103 fixed on the base 101 , and a mass 102 movable relative to the fixed electrode 103 .
  • the mass 102 includes a moving component 1021 and a conductive electrode 104 located above the moving component 1021.
  • the conductive electrode 104 and the fixed electrode 103 are configured to form a capacitor, and the capacitance of the capacitor may be variable due to the movement of the mass 102 relative to the base 101. For example, the overlapping area of the orthographic projection of the conductive electrode 104 and the orthographic projection of the fixed electrode 103 is variable.
  • the orthographic projection of the fixed electrode 103 is a projection of the fixed electrode 103 on the surface of the base 101 in a direction perpendicular to the base 101
  • the orthographic projection of the conductive electrode 104 is the surface of the conductive electrode 104 in the direction perpendicular to the base 101 at the surface of the base 101. Projection on.
  • the fixed electrode 103 is located above or below the conductive electrode 104
  • the orthographic projection of the fixed electrode 103 and the orthographic projection of the conductive electrode 104 overlap each other, and with the movement of the acceleration sensor 100, the overlap area is due to the mass 102 and
  • the relative movement of the base 101 can vary. Referring to Fig.
  • the conductive electrode 104 and the fixed electrode 103 overlap, and the overlapping area is variable.
  • the conductive electrode 104 and the fixed electrode 103 are configured to form a capacitor.
  • the acceleration sensor 100 is small in size, is easy to integrate, and is not susceptible to temperature due to the absence of the interdigitated structure.
  • the base 101 can be a horizontally placed substrate (eg, the substrate is horizontally secured in the vehicle), and accordingly, the acceleration sensor 100 is used to sense acceleration in the horizontal direction.
  • the conductive electrode 104 and the fixed electrode 103 overlap in the vertical direction and form an overlapping area.
  • the overlap area may include the rectangular area in which the conductive electrode 104 is shown in the dashed box of FIG.
  • the embodiment of the present disclosure does not limit the placement direction of the base 101.
  • the placement direction of the base 101 can be determined according to the direction of the acceleration that needs to be detected.
  • the moving member 1021 includes a rectangular area, and a conductive layer corresponding to the conductive electrode 104 is disposed in the rectangular area.
  • the rectangular area may include a portion of the orthographic projection formed by the fixed electrode 103 on the surface of the moving part 1021 when the acceleration is 0, and a portion of the orthographic projection coincides with the moving part 1021.
  • the moving member 1021 can be composed of a thicker silicon single crystal substrate portion.
  • conductive electrode 104 is a separate conductive component that is secured to moving component 1021, which is fabricated from an insulative material.
  • the conductive electrode 104 is embedded on the moving component 1021, that is, the conductive electrode 104 is integrally formed with or is part of the moving component 1021, which is made of a conductive material.
  • the movable component 1021 and the conductive electrode 104 can also adopt other suitable arrangements, which are not limited by the embodiments of the present disclosure.
  • embodiments of the present disclosure may also sense accelerations in a plurality of different directions by providing a plurality of acceleration sensors 100.
  • a dielectric layer 109 is disposed between the fixed electrode 103 and the conductive electrode 104 included in the acceleration sensor 100.
  • the material of the dielectric layer 109 may include, but is not limited to, paraffin, mica, diamond, polyester, and the like.
  • the acceleration sensor 100 including the dielectric layer 109 will be exemplarily described below using FIG. 2 as an example.
  • the acceleration sensor 100 shown in FIG. 2 includes a base 101, a mass 102, a dielectric layer 109, and a fixed electrode 103.
  • the mass 102 includes a moving part 1021.
  • a conductive electrode 104 for example, the base 101, the moving member 1021, the conductive electrode 104, the dielectric layer 109, and the fixed electrode 103 are disposed in order from bottom to top.
  • the mass 102 (or the moving part 1021) shown in FIG. 2 is not in close contact with the base 101 in order to allow the mass 102 to move in parallel with respect to the base 101.
  • the distance between the mass 102 and the base 101 can be 0.5 mm.
  • the conductive electrode 104 can also be embedded in the moving part 1021.
  • the base 101, the fixed electrode 103, the dielectric layer 109, the conductive electrode 104, and the moving member 1021 may be disposed in order from bottom to top, and embodiments of the present disclosure are not limited herein.
  • the capacitance value of the plate capacitor having the overlapping area composed of the fixed electrode 103 and the conductive electrode 104 can be effectively improved. Since the capacitance value of the capacitor is increased, the sensitivity of the acceleration sensor 100 to the acceleration is improved.
  • the acceleration sensor 100 may further include a cantilever beam 105 disposed on the base 101, and the mass 102 (or moving member 1021) is coupled to the cantilever beam 105.
  • the mass 102 can be attached to the base 101 by a cantilever beam 105.
  • a cantilever beam 105 may be coupled to the base 101 by a first fixing member 106, and the other end of the cantilever beam 105 may be coupled to the mass block 102 by a second fixing member 107.
  • the first fixing member 106 may be stacked using a micromachining process.
  • the second fixing member 107 includes a screw.
  • the cantilever beam 105 includes a spring or other resilient member that is deformable (eg, a rigid cantilever beam).
  • the acceleration sensor 100 shown in FIG. 1 includes four cantilever beams 105 that can undergo a certain elastic deformation. Embodiments of the present disclosure do not limit the number of cantilever beams 105.
  • a spring is employed as the cantilever beam 105, and the magnitude of the distance the mass 102 moves is related to the spring force of the spring.
  • the acceleration sensor 100 using the spring as the cantilever beam 105 is relatively large in volume
  • the acceleration sensor 100 using the rigid cantilever beam as the cantilever beam 105 is relatively small in volume.
  • both ends of the fixed electrode 103 are also fixed to the base 101 by the fixing member 108.
  • the fixed component 108 can be stacked using a micromachining process.
  • the acceleration sensor 100 of FIG. 1 further includes a first wire 205 electrically connected to the fixed electrode 103, and a second wire 206 electrically connected to the conductive electrode 104.
  • the embodiment of the present disclosure does not limit the installation position of the second wire 206 on the mass block 102, that is, the second wire 206 may also be disposed at other positions than those of FIG. 1 as long as the second wire is ensured.
  • 206 can be electrically connected to the conductive electrode 104.
  • the embodiment of the present disclosure may output the capacitance value of the capacitor in the acceleration sensor 100 through the first wire 205 and the second wire 206, so that the capacitance detecting circuit converts this capacitance value into a detection signal.
  • the embodiments of the present disclosure do not limit the number of conductive electrodes 104 disposed on the mass 102, and the corresponding embodiments of the present disclosure do not limit the number of fixed electrodes 103 that are fixed on the base 101.
  • a plurality of conductive electrodes 104 and a plurality of fixed electrodes 103 By providing a plurality of conductive electrodes 104 and a plurality of fixed electrodes 103, a plurality of parallel plate capacitors can be obtained, thereby improving the sensitivity of the acceleration sensor 100 when sensing acceleration.
  • n conductive electrodes 104a...104n are disposed in parallel and gap on the moving member 1021 of the mass 102 of the acceleration sensor 100, and correspondingly, n fixed electrodes are disposed in parallel and gap on the base 101.
  • 103a...103n where n is an integer greater than one.
  • the n conductive electrodes 104a...104n are arranged in parallel along the moving direction of the mass block 102 with respect to the base 101, and the n fixed electrodes 103a...103n are also arranged in parallel along the moving direction of the mass block 102 with respect to the base 101, n conductive The electrodes 104a...104n are in one-to-one correspondence with the n fixed electrodes 103a...103n.
  • Fig. 3A also shows a plurality of fixing members 108a ... 108n for fixing these fixed electrodes on the base 101.
  • FIG. 3B is a cross-sectional view of the acceleration sensor 100 taken along line B-B of FIG. 3A.
  • a dielectric layer 109 is also provided between each of the conductive electrodes 104a ... 104n and the two plates of each of the fixed electrodes 103a ... 103n.
  • the positional relationship between the layers of the acceleration sensor 100 in FIG. 3B can be adjusted.
  • the base 101 a plurality of fixed electrodes 103a...103n disposed in parallel and gap, a dielectric layer 109 disposed corresponding to the plurality of fixed electrodes 103a...103n, and a plurality of parallel and gap-arranged portions may be disposed.
  • the conductive electrodes 104a to 104n and the moving member 1021 are sequentially disposed from bottom to top.
  • the acceleration sensor 100 of the above-described embodiment of the present disclosure can satisfy a linear relationship between the capacitance value of the capacitor and the acceleration perceived by the acceleration sensor 100, and the linear relationship between the two will be described below with reference to FIGS. 4-7B.
  • FIG. 1 is a schematic diagram of the acceleration sensor 100 when the acceleration is 0, and FIG. 4 is a schematic diagram of the deformation of the acceleration sensor 100 according to the embodiment of the present disclosure when the acceleration is a.
  • the acceleration sensor 100 of FIG. 4 causes a relative displacement between the mass 102 and the base 101 under the action of the acceleration a, and causes an overlapping area between the conductive electrode 104 and the fixed electrode 103 to change (for example, in FIG. 4
  • the conductive electrode 104 has a partial area that is removed from the rectangular overlap region shown in FIG.
  • the end of the cantilever beam 105 connected to the mass block 102 is also deformed.
  • FIGS. 5A-5D To illustrate the shape variables of FIG. 4 with respect to FIG. 1, reference may further be made to FIGS. 5A-5D.
  • FIGS. 5A and 5D only the rigid cantilever beam is taken as an example, and the relevant calculation formula is derived, but this does not constitute a limitation on the embodiment of the present disclosure.
  • the acceleration of the acceleration sensor 100 in FIG. 5A is 0, and the initial capacitance value C0 of the corresponding capacitor is as shown in FIG. 6A.
  • the acceleration of the acceleration sensor 100 in FIG. 5C is a, the displacement of the mass 102 with respect to the initial position of FIG. 5A under the action of the acceleration a is w, and the capacitance value C of the capacitor of the acceleration sensor 100 at this time is as shown in FIG. 6B. Show.
  • the distance that the mass 102 moves to the left under the action of the acceleration a is w. Since each of the four cantilever beams 105 has one end connected to the mass 102, the moving distance is also w.
  • F represents the force of the single cantilever beam 105 on the mass block 102 (as shown in FIG. 5B)
  • m represents the mass of the mass block 102
  • a represents the acceleration of the acceleration sensor 100.
  • EI in the above formula 2 represents the bending rigidity of the cantilever beam 105, where E represents the elastic modulus of the cantilever beam 105 (i.e., the stress required to generate a unit strain), and I represents the material cross-section of the cantilever beam 105 facing the bending.
  • the moment of inertia of the neutral axis; L represents the length of the cantilever beam 105 (as shown in Figure 5B).
  • the overlapping area between the fixed electrode 103 and the conductive electrode 104 is S 0 .
  • the overlapping area between the fixed electrode 103 and the conductive electrode 104 becomes S.
  • the capacitance value C (or C 0 ) of the capacitor formed by the acceleration sensor 100 and the overlapping area S (or S 0 ) between the fixed electrode 103 and the conductive electrode 104 are Both are positively related linear relationships. That is, the larger the overlap area S, the larger the capacitance value C.
  • ⁇ r in the above formulas 3 and 5 represents the dielectric constant of the dielectric layer 109
  • ⁇ represents the pi
  • k represents the electrostatic constant
  • d represents the thickness of the dielectric layer 109 between the fixed electrode 103 and the conductive electrode 104 (as shown in FIG. 6A).
  • b in the above formulas 4 and 6 represents the width of the mass 102 (as shown in FIG. 5A)
  • e represents the width of the fixed electrode 103 (as shown in FIG. 5A)
  • w represents the mass 102 relative to the acceleration a.
  • the displacement of the base 101 (as shown in Figures 5C and 5D).
  • the calculation relationship between the acceleration a and the capacitance value C can be obtained by combining the above formulas 1 to 6 as follows:
  • the parameter K 1 in the above formula 7 is a constant, and its size is
  • the linear relationship between the acceleration a of the acceleration sensor 100 and the capacitance value C (for example, a linear relationship of negative correlation). That is, the larger the capacitance value C, the smaller the acceleration a. Therefore, the embodiment of the present disclosure only needs to monitor the capacitance value C of the capacitor of the acceleration sensor 100, and the magnitude of the acceleration a can be determined.
  • a linear relationship for example, a negative correlation relationship
  • Fig. 7B also provides a graph of the relationship between the acceleration a and the capacitance value C of an interdigital acceleration sensor. As can be seen from FIG. 7B, the acceleration a of the interdigital acceleration sensor and the capacitance value C satisfy a nonlinear (ie, curve) relationship.
  • the acceleration sensor 100 provided by the embodiment of the present disclosure has a technical effect of facilitating data collection, processing, and calculation.
  • the capacitance detecting circuit 200 provided by the embodiment of the present disclosure will be described below with reference to FIGS. 8-11B.
  • the capacitance detecting circuit 200 of the embodiment of the present disclosure can be used to monitor the capacitance value of the capacitor included in the acceleration sensor 100 provided in FIG. 1 to FIG. 7A, and can also monitor the capacitance value obtained by other capacitance type acceleration sensors. .
  • the capacitance detecting circuit 200 provided by the embodiment of the present disclosure may also be used to monitor the capacitance value of the capacitor of the interdigital acceleration sensor.
  • the embodiment of the present disclosure monitors the capacitance value of the capacitor included in the acceleration sensor through the capacitance detecting circuit 200, and converts the monitoring result into a detection signal (for example, a square wave signal) that is convenient for processing.
  • a detection signal for example, a square wave signal
  • the capacitance detecting circuit 200 can be used to monitor the capacitance value of the capacitor of the above-described acceleration sensor 100.
  • the capacitance detecting circuit 200 shown in FIG. 8 includes a first capacitor C1 and a detecting sub-circuit 202, wherein both ends of the first capacitor C1 are electrically connected to the fixed electrode 103 and the conductive electrode 104 of the acceleration sensor 100, respectively (for example, the first The two plates of the capacitor C1 may be respectively connected to the first wire 205 and the second wire 206); the detecting sub-circuit 202 is configured to convert the capacitance value of the first capacitor C1 into the detection signal S1 and output the detection signal S1.
  • the capacitance value of the first capacitor C1 is equal to the capacitance value of the capacitor of the acceleration sensor 100.
  • the fixed electrode 103 and the conductive electrode 104 in the acceleration sensor 100 may serve as two plates of the first capacitor C1.
  • the detecting sub-circuit 202 may include: a first switch SW1, a second switch SW2, a third switch SW3, a second capacitor C2, a resistor R0, a generating sub-circuit 2021, and The sub-circuit 2022 is stored.
  • the first switch SW1, the second switch SW2, and the third switch SW3 may be switching transistors.
  • the first capacitor C1 is configured to perform charging when the first switch SW1 is turned on; and when the first switch SW1 is turned off, the second switch SW2 and the third switch SW3 are both turned on, discharging is performed and the second capacitor C2 is performed Charging.
  • the generating sub-circuit 2021 is configured to generate the detection signal S1 according to the voltage of the second capacitor C2 and the reference voltage Vref, wherein the generated detection signal S1 is at the first level when the voltage of the second capacitor C2 is lower than the reference voltage Vref When the voltage of the second capacitor C2 is not lower than the reference voltage Vref, the generated detection signal S1 is at the second level.
  • the first level is a voltage signal that is lower than the second level.
  • the first level is a low level of the square wave signal and the second level is a high level of the square wave signal.
  • the second capacitor C2 is configured to discharge through the resistor R0 when the detection signal S1 is at a second level (eg, a high level). For example, the second capacitor C2 is discharged by the switching unit when the detection signal S1 is at a high level.
  • a second level eg, a high level
  • the capacitance value of the second capacitor C2 is smaller than the capacitance value of the first capacitor C1.
  • the reference voltage Vref can be set smaller so that the second capacitor C2 completes the discharge process faster.
  • the storage sub-circuit 2022 is configured to buffer and output the detection signal S1.
  • the first capacitor C1 is charged by the first voltage V dd , and then the amount of charge stored on the first capacitor C1 is measured by the number of discharges of the second capacitor C2, thereby determining the first capacitor C1.
  • the size of the capacitance value Therefore, the capacitance detecting circuit 200 provided by the embodiment of the present disclosure can effectively improve the sensitivity and speed of the capacitance value detection.
  • the detecting sub-circuit 202 further includes: a first inverter B1 configured to invert the clock signal CLK input from the clock signal terminal and output to the gate of the first switch SW1.
  • the second inverter B2 is configured to invert the detection signal S1 and output to the control electrode of the third switch SW3 such that when the detection signal S1 is at the first level (eg, low level), the third switch SW3 is turned on.
  • the embodiment of the present disclosure controls the on or off of the first switch SW1 by the clock signal CLK, and controls the on or off of the third switch SW3 by the detection signal S1.
  • the detecting sub-circuit 202 further includes a fourth switch SW4 configured to be turned on when the detection signal S1 is at a second level (eg, a high level), so that the second capacitor C2 is discharged through the resistor R0. .
  • a fourth switch SW4 configured to be turned on when the detection signal S1 is at a second level (eg, a high level), so that the second capacitor C2 is discharged through the resistor R0.
  • the input end of the first inverter B1 is connected to the clock signal terminal to receive the clock signal CLK, and the output end of the first inverter B1 is connected to the control electrode of the first switch SW1; the second inverter The input end of the B2 is connected to the output end of the generating sub-circuit 2021, the output end of the second inverter B2 is connected to the control electrode of the third switch SW3; the first pole of the first switch SW1 is connected to the first power supply end to receive the input.
  • the first voltage V dd the second pole is connected to the first end of the first capacitor C1; the second end of the first capacitor C1 is grounded; the control pole of the second switch SW2 is connected to the clock signal end to receive the clock signal CLK
  • the first pole is connected to the first end of the first capacitor C1, the second pole is connected to the first end of the second capacitor C2, the first pole of the third switch SW3 is connected to the second end of the second capacitor C2, and the second The pole is connected to the second end of the first capacitor C1; and the control pole of the fourth switch SW4 is connected to the output end of the generating sub-circuit 2021, the first pole is connected to the first end of the resistor R0, and the second pole and the second capacitor C2 are connected The second end of the connection.
  • the generating sub-circuit 2021 may include a comparator; the non-inverting input terminals of the comparator are respectively connected to the first end of the second capacitor C2 and the second end of the resistor R0, and the inverting input terminal is connected to the reference voltage end. To receive the reference voltage Vref, the output terminal is connected to the input terminal of the second inverter B2.
  • the memory sub-circuit 2022 includes a latch whose input is coupled to the output of the generating sub-circuit 2021, the output of which acts as the output of the capacitance detecting circuit 200.
  • FIG. 9B is different from the detection sub-circuit 202 of FIG. 9A in that the first switch SW1 and the second switch SW2 are respectively controlled by two clock signals (ie, the first clock signal CLK1 and the second clock signal CLK2) in FIG. 9B.
  • the first inverter B1 shown in FIG. 9A can be omitted.
  • the control electrode of the first switch SW1 shown in FIG. 9B is connected to the first clock signal terminal to receive the input first clock signal CLK1
  • the control electrode of the second switch SW2 is connected to the second clock signal terminal to receive the input.
  • the generation sub-circuit 2021 of FIG. 9B may also include a comparator, and the connection manner of the comparator may refer to FIG. 9A.
  • the memory sub-circuit 2022 of FIG. 9B may also include a latch, and the specific connection of the latch may refer to FIG. 9A.
  • the other circuit elements of FIG. 9B are not described again, and the related content may refer to the content shown in FIG. 9B or refer to the above explanation for FIG. 9A.
  • the detection signal S1 generated and output by the capacitance detecting circuit 200 shown in FIGS. 9A and 9B includes a square wave signal, and the number of pulses of the square wave signal is linear with the acceleration of the acceleration sensor 100.
  • the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 of FIG. 9A are all transistors that are turned on at a high level (for example, an N-type transistor).
  • the embodiments of the present disclosure do not limit that the above four switch units must be turned on at a high level.
  • one or more of the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 may also employ a low-level conducting transistor (eg, a P-type transistor).
  • the clock signal CLK of FIG. 9A is set low, the corresponding first switch SW1 is turned on (closed), and the second switch SW2 is turned off (opened), and the first voltage V dd is quickly charged to the first capacitor C1. .
  • the clock signal CLK is set high.
  • the first switch SW1 is turned off and the second switch SW2 is turned on, and the charge on the first capacitor C1 is charged to the second capacitor C2.
  • the comparator outputs a high level pulse that is transferred to the latch for latching. Meanwhile, the comparator outputs a high level pulse is also the third switch SW3 is turned off, the fourth switch SW4 is turned on after the second capacitor C2 will discharge resistor R 0.
  • the above second step process is repeated until the charge of the first capacitor C1 is completely released.
  • the control poles of the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 are connected to the high level by the numeral "1".
  • the numeral "0" indicates that the control electrodes of the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 are connected to the low level.
  • the number "1" in the table of the second switch SW2 indicates that the clock signal CLK is at a high level
  • the number "0" indicates that the clock signal CLK is at a low level
  • the number "1" in the table of the fourth switch SW4 indicates detection.
  • the signal S1 is at a high level
  • the number "0" indicates that the detection signal S1 is at a low level.
  • N in the above formula 8 represents the number of times the second level (i.e., the high level) of the detection signal S1 is output, and also indicates the number of times of discharge of the second capacitor C2 (refer to the subsequent FIG. 10A or FIG. 10B); C indicates the first capacitor.
  • the capacitance value of C1, Cint represents the capacitance value of the second capacitor C2.
  • the relative magnitude of the capacitance value of the first capacitor C1 can be directly determined by statistically detecting the number of high levels N in the signal S1.
  • FIGS. 10A and 10B are diagrams showing a charge and discharge process of the second capacitor C2 corresponding to the above-described operation of FIG. 9A and a waveform diagram of the detection signal S1.
  • FIGS. 10A and 10B are waveform diagrams of the detection signal S1 output by the capacitance detecting circuit 200 and charging and discharging processes of the second capacitor C2 of the acceleration sensor 100 at different accelerations a.
  • 10A is a waveform diagram of the detection signal S1 in the case of a large acceleration and a charging and discharging process diagram of the second capacitor C2
  • FIG. 10B is a waveform diagram of the detection signal S1 in the case of a small acceleration and charging and discharging of the second capacitor C2. Process diagram.
  • the detection signal S1 when the second capacitor C2 is charged, the detection signal S1 outputs a low level signal; when the second capacitor C2 is discharged, the detection signal S1 outputs a high level signal. Therefore, the number of high levels occurring in the detection signal S1 is equal to the number of discharges of the second capacitor C2.
  • the voltage V2 of the second capacitor C2 when the voltage V2 of the second capacitor C2 is raised to the reference voltage Vref by charging, the second capacitor C2 starts the discharging process, and the corresponding detecting signal S1 outputs a high level during the discharging.
  • the larger the acceleration of the acceleration sensor 100 the smaller the number N of high levels of the latch output in the storage sub-circuit 2022. This is because the larger the acceleration a of the acceleration sensor 100 is, the larger the displacement of the mass 102 in the acceleration sensor 100 is, so that the capacitance value of the capacitor of the acceleration sensor 100 is smaller (the capacitance value C of the first capacitor C1 is also smaller). ).
  • the capacitance value of the capacitor of the acceleration sensor 100 is smaller, the charging speed of the second capacitor C2 is slower, and the frequency of the waveform of the detection signal S1 output by the latch in the corresponding storage sub-circuit 2022 is lower, that is, The number N of times of the high level of the latch output in the storage sub-circuit 2022 in the same period of time is also less.
  • the parameter K 1 in the above formula 9 is a constant, specifically:
  • the parameter K 2 in the above formula 9 is a constant, specifically
  • the relationship between the acceleration a sensed by the acceleration sensor 100 and the number N of high levels in the detection signal S1 of the latch output in the storage sub-circuit 2022 can be obtained as shown in FIG. 11A in combination with the above formula 9.
  • the acceleration a perceived by the acceleration sensor 100 and the number N of outputs of the high level in the detection signal S1 satisfy a linear relationship.
  • the acceleration a and the number of discharges of the second capacitor C2 satisfy a linear relationship.
  • a linear negative correlation between the acceleration a and the number of high-level outputs N included in the detection signal S1 can be utilized to monitor whether the vehicle has collided.
  • the embodiment of the present disclosure can solve the output of the detection signal S1 corresponding to the maximum acceleration threshold a max by using the above formula 9.
  • the number of high levels is Nmin. After that, when it is judged that the number N of high levels outputted by the detection signal S1 is less than or equal to Nmin, it can be directly found that the vehicle has collided.
  • the embodiment of the present disclosure can directly determine the magnitude of the capacitance value (or further determine the magnitude of the acceleration), and the calculation amount is reduced and improved.
  • the processing speed By analyzing the high-order number N included in the detection signal S1 outputted by the capacitance detecting circuit 200, the embodiment of the present disclosure can directly determine the magnitude of the capacitance value (or further determine the magnitude of the acceleration), and the calculation amount is reduced and improved. The processing speed.
  • FIG. 11C is a relationship diagram between the obtained acceleration a and the high-level output number N when the interdigital acceleration sensor is matched with the capacitance detecting circuit 200 of the embodiment of the present disclosure.
  • the nonlinearity (ie, curve) relationship is satisfied between the acceleration a and the high-level output number N. If the interdigital acceleration sensor and the capacitance detecting circuit 200 are used, it is also possible to determine the magnitude of the acceleration a by the number N of high levels in the statistical detection signal S1.
  • the capacitance detecting method 300 includes: step S301, charging the first capacitor C1; and step S302, repeating the charging and discharging operation until the discharging of the first capacitor C1 is completed, wherein the charging and discharging operation includes: The first capacitor C1 discharges to charge the second capacitor C2; and discharges the second capacitor C2; and in step S303, according to the voltage of the second capacitor C2 (for example, the voltage V2 shown in FIGS.
  • the voltage Vref generates a detection signal S1, wherein when the voltage of the second capacitor C2 is lower than the reference voltage Vref, the generated detection signal S1 is at a first level, and when the voltage of the second capacitor C2 is not lower than the reference voltage Vref, The generated detection signal S1 is at the second level; and in step S304, the detection signal S1 is buffered and output.
  • the first level is a low level of the square wave signal and the second level is a high level of the square wave signal.
  • At least one embodiment of the present disclosure also provides an acceleration processing circuit 400 that can be coupled to the acceleration sensor 100 described in the above embodiments.
  • an acceleration processing circuit 400 that can be coupled to the acceleration sensor 100 described in the above embodiments.
  • the acceleration sensor 100 reference may be made to the description of FIG. 1 to FIG. 7A, and details are not described herein.
  • the acceleration processing circuit 400 includes the above-described capacitance detecting circuit 200, acceleration calculating sub-circuit 401, and processing sub-circuit 402, wherein the capacitance detecting circuit 200 is configured to output a detection signal S1 to an acceleration calculating sub-circuit 401;
  • the calculation sub-401 circuit is configured to calculate an associated parameter value of the acceleration based on the detection signal S1; and the processing sub-circuit 402 is configured to perform an operation corresponding to the associated parameter value of the acceleration based on the associated parameter value of the acceleration (eg, a motor vehicle Security measures).
  • the acceleration processing circuit 400 may also include an acceleration sensor 100.
  • the associated parameter values are linear with the acceleration measured by the acceleration sensor.
  • the detection signal S1 includes a square wave signal
  • the associated parameter value includes the number of pulses of the square wave signal (for example, the number of high-level outputs N described above).
  • the detection signal S1 output by the capacitance detecting circuit 200 is a square wave signal
  • the processing sub-circuit 402 is configured to when the number of pulses of the square wave signal is less than a set threshold (for example, Nmin shown in FIG. 11B is When setting the threshold), perform security measures.
  • security measures include: turning on the airbag, making an alarm call, sending a reminder message, or generating a warning signal (eg, generating an alert signal may include activating a car double flash signal, etc.).
  • the capacitance detecting circuit 200 included in the acceleration processing circuit 400 may be specifically referred to the description of FIG. 8 to FIG. 9B, and details are not described herein.
  • the acceleration processing circuit 400 described above can be employed to determine if a collision has occurred in the vehicle.
  • the acceleration processing circuit 400 can quickly determine whether the acceleration exceeds the safety threshold according to the associated parameter value of the acceleration, thereby starting the safety protection measure in time, and effectively protecting the personal safety of the driver and the passenger.
  • At least one embodiment of the present disclosure also provides an acceleration processing method 500 that can be used in the acceleration processing circuit 400.
  • the acceleration processing method 500 may include: step S501, monitoring a capacitor in the acceleration sensor 100 and converting the monitoring result into a detection signal S1; step S502, calculating an associated parameter value of the acceleration according to the detection signal S1; S503: Perform corresponding security protection measures according to the associated parameter value of the acceleration.
  • the detection signal S1 is a square wave signal.
  • step S502 includes: counting the number of pulses of the square wave signal in a predetermined time period, and step S503 includes: determining whether the number of pulses is less than a set threshold; and executing when the number of pulses is less than a set threshold Security measures.
  • the set threshold may be Nmin as shown in FIG. 11B.
  • security measures include: turning on the airbag, making an alarm call, sending a reminder message, or generating an alert signal (eg, the alert signal can include a double flash signal, etc.).
  • the embodiment of the present disclosure further provides a structure of the package acceleration sensor 100 and the capacitance detecting circuit 200.
  • the acceleration sensor 100 may be a microelectromechanical system (MEMS) based acceleration sensor, that is, an embodiment of the present disclosure may be processed on the silicon wafer 1530 to form an inertial measurement element (ie, the acceleration sensor 100) by a micromachining process.
  • Embodiments of the present disclosure also construct a capacitance detection circuit 200 based on an application specific integrated circuit (ASIC). Since the micromachining process and an application specific integrated circuit (ASIC) employ a similar process, the acceleration sensor 100 and the capacitance detecting circuit 200 can be integrated on the package substrate 1510 and the printed circuit board 1500.
  • the acceleration sensor 100 can be fabricated using micromachining technology and the capacitance sensing circuit 200 can be fabricated using an application specific integrated circuit (ASIC) process technique, and then both are bonded within the same package 1503 (as shown in FIG. 15).
  • ASIC application specific integrated circuit
  • the cap 1520 can also be employed to protect the acceleration sensor 100.
  • a first wire 205 electrically connected to the fixed electrode 103 of the acceleration sensor 100 and a second wire 206 electrically connected to the conductive electrode 104 are also shown in FIG.
  • acceleration processing circuit 400 of the above embodiment of the present disclosure may also be configured based on an application specific integrated circuit (ASIC), and thus the capacitance detecting circuit 200 illustrated in FIG. 15 may be replaced with the acceleration processing circuit 400. Finally, the purpose of packaging the acceleration sensor 100 and the acceleration processing circuit 400 together is achieved.
  • ASIC application specific integrated circuit
  • the embodiment of the present disclosure encapsulates the acceleration sensor 100 and the capacitance detecting circuit 200 (or the acceleration processing circuit 400) with reference to FIG. 15, which can improve the stability of the entire device.
  • At least one embodiment of the present disclosure also provides a storage medium having computer instructions stored thereon, wherein the computer instructions are executed by the processor to perform one or more steps of the acceleration processing method 500.
  • a storage medium may comprise any combination of one or more computer program products, which may comprise various forms of computer readable memory, such as volatile memory and/or nonvolatile memory.
  • Volatile memory can include, for example, random access memory (RAM) and/or caches and the like.
  • the non-volatile memory may include, for example, a read only memory (ROM), a hard disk, an erasable programmable read only memory (EPROM), a portable compact disk read only memory (CD-ROM), a USB memory, a flash memory, and the like.
  • ROM read only memory
  • EPROM erasable programmable read only memory
  • CD-ROM portable compact disk read only memory
  • USB memory a flash memory
  • One or more computer program modules can be stored on the storage medium, and one or more steps in the acceleration processing method 500 can be implemented when the one or more computer program modules are executed.
  • Various applications and various data as well as various data used and/or generated by the application, and the like can also be stored in the storage medium.
  • At least one embodiment of the present disclosure also provides an electronic device including one or more processors configured to execute computer instructions to perform one or more steps in the acceleration processing method 500.
  • the processor can be a central processing unit (CPU), a digital signal processor (DSP), or other form of processing unit with data processing capabilities and/or program execution capabilities, such as a field programmable gate array (FPGA), etc.;
  • the central processing unit (CPU) can be an X86 or ARM architecture or the like.
  • the processor can be a general purpose processor or a special purpose processor that can execute computer instructions to perform one or more steps in the acceleration processing method 500.

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Abstract

一种加速度传感器（100），包括：底座（101）；固定于底座（101）之上的固定电极（103）；以及相对于固定电极（103）可移动的质量块（102）；其中，质量块（102）包括导电电极（104），导电电极（104）与固定电极（103）被配置为形成电容器，并且该电容器的电容可由于质量块（102）相对于底座（101）的移动而可变。还提供一种电容检测电路及方法、加速度处理电路及方法、存储介质和电子设备。

Description

加速度传感器、电容检测电路及方法、加速度处理电路及方法、存储介质和电子设备
本申请要求于2018年3月14日递交的中国专利申请第201810208512.5号的优先权，该中国专利申请的全文以引入的方式并入以作为本申请的一部分。
技术领域
本公开的实施例涉及一种加速度传感器、电容检测电路及方法、加速度处理电路及方法、存储介质和电子设备。
背景技术
加速度传感器具有体积小、质量轻且方便灵活等特点，因此在飞行器控制、汽车安全等领域有着广泛的应用。
加速度传感器的类型有压阻式、压电式、谐振式、隧道电流式和电容式等。电容式微加速度传感器具有结构简单、输出稳定、温度漂移小且易于测试集成等优点，有利于大规模生产。
发明内容
本公开的至少一个实施例提供一种加速度传感器，包括：底座；固定于所述底座之上的固定电极；以及相对于所述固定电极可移动的质量块；其中，所述质量块包括导电电极，所述导电电极与所述固定电极被配置为形成电容器，并且所述电容器的电容可由于所述质量块相对于所述底座的移动而可变。
在一些实施例中，所述加速度传感器还包括位于所述导电电极和所述固定电极之间的电介质层。
在一些实施例中，所述加速度传感器还包括位于所述底座上的悬臂梁，所述质量块连接在所述悬臂梁上。
在一些实施例中，所述悬臂梁的一端与所述底座连接，所述悬臂梁的另一端与所述质量块连接。
在一些实施例中，所述悬臂梁包括弹簧。
在一些实施例中，所述电容器的电容值与所述加速度传感器的加速度为线性关系。
在一些实施例中，所述固定电极为多个，多个所述固定电极在所述底座上间隙分布。
在一些实施例中，多个所述固定电极沿所述质量块相对于所述底座的移动方向平行排列。
本公开的至少一个实施例还提供一种电容检测电路，用于监测所述加速度传感器的电容器的电容值，包括：第一电容器和检测子电路；其中，所述第一电容器的两端分别与所述加速度传感器的固定电极和导电电极电气相连；以及所述检测子电路被配置为将所述第一电容器的电容值转换为检测信号，并输出所述检测信号。
在一些实施例中，所述检测子电路包括：第一开关、第二开关、第三开关、第二电容器、电阻、生成子电路以及存储子电路；其中，所述第一电容器被配置为：响应于所述第一开关导通进行充电；以及响应于所述第一开关截止、所述第二开关和所述第三开关均导通进行放电并对所述第二电容器进行充电；所述生成子电路被配置为根据所述第二电容器的电压和参考电压，生成所述检测信号，其中，当所述第二电容器的电压低于所述参考电压时，生成的所述检测信号处于第一电平，当所述第二电容器的电压不低于所述参考电压时，生成的所述检测信号处于第二电平；所述第二电容器被配置为响应于所述检测信号处于所述第二电平，通过所述电阻进行放电；以及所述存储子电路被配置为缓存并输出所述检测信号。
在一些实施例中，所述检测子电路还包括：第一反相器，被配置为将时钟信号端输入的时钟信号反相并输出至所述第一开关的控制极；以及第二反相器，被配置将所述检测信号反相并输出至所述第三开关的控制极，使得当所述检测信号处于所述第一电平时，所述第三开关导通。
在一些实施例中，所述检测子电路还包括：第四开关，被配置为响应于所述检测信号处于所述第二电平而导通，使得所述第二电容器通过所述电阻放电。
在一些实施例中，所述第一反相器的输入端与所述时钟信号端连接，所 述第一反相器的输出端与所述第一开关的控制极连接；所述第二反相器的输入端与所述生成子电路的输出端连接，所述第二反相器的输出端与所述第三开关的控制极连接；所述第一开关的第一极与第一电源端连接以接收输入的第一电压，所述第一开关的第二极与所述第一电容器的第一端连接；所述第一电容器的第二端接地；所述第二开关的控制极与所述时钟信号端连接以接收所述时钟信号，所述第二开关的第一极与所述第一电容器的第一端连接，所述第二开关的第二极与所述第二电容器的第一端连接；所述第三开关的第一极与所述第二电容器的第二端连接，所述第三开关的第二极与所述第一电容器的第二端连接；以及所述第四开关的控制极与所述生成子电路的输出端连接，所述第四开关的第一极与所述电阻的第一端连接，所述第四开关的第二极与所述第二电容器的第二端连接。
在一些实施例中，所述生成子电路包括比较器；所述比较器的正相输入端分别与所述第二电容器的第一端和所述电阻的第二端连接，所述比较器的反相输入端与参考电压端连接以接收所述参考电压，所述比较器的输出端与所述第二反相器的输入端连接。
在一些实施例中，所述存储子电路包括锁存器，所述锁存器的输入端与所述生成子电路的输出端连接。
在一些实施例中，所述检测信号包括方波信号，所述方波信号的脉冲个数与所述加速度传感器的加速度为线性关系。
本公开的至少一个实施例还提供一种用于所述电容检测电路的电容检测方法，包括：对所述第一电容器进行充电；重复充放电操作直至所述第一电容器的电荷释放完毕，其中，所述充放电操作包括：通过对所述第一电容器进行放电，实现对第二电容器进行充电；以及对所述第二电容器进行放电；根据所述第二电容器的电压和参考电压，生成所述检测信号，其中，当所述第二电容器的电压低于所述参考电压时，生成的所述检测信号处于第一电平，当所述第二电容器的电压不低于所述参考电压时，生成的所述检测信号处于第二电平；以及缓存并输出所述检测信号。
本公开的至少一个实施例还提供一种加速度处理电路，包括所述电容检测电路、加速度计算子电路和处理子电路；其中，所述电容检测电路被配置为输出所述检测信号至所述加速度计算子电路；所述加速度计算子电路被配 置为根据所述检测信号，计算加速度的关联参数值；以及所述处理子电路被配置为根据所述加速度的关联参数值，执行与所述关联参数值相应的操作。
在一些实施例中，所述关联参数值与所述加速度传感器测得的加速度为线性关系。
在一些实施例中，所述检测信号包括方波信号，所述关联参数值包括所述方波信号的脉冲个数。
在一些实施例中，所述处理子电路被配置为当所述方波信号的脉冲个数小于设定阈值时，执行所述操作。
在一些实施例中，所述操作包括：打开安全气囊、拨打报警电话、发出提示信息或者生成警示信号。
本公开的至少一个实施例还提供一种用于所述加速度处理电路的加速度处理方法，包括：监测所述加速度传感器中的电容器并将监测结果转换为所述检测信号；根据所述检测信号，计算所述加速度的关联参数值；以及根据所述加速度的关联参数值，执行与所述关联参数值相应的操作。
在一些实施例中，所述检测信号为方波信号；所述根据所述检测信号，计算所述加速度的关联参数值，包括：在预定时间段内，统计所述方波信号的脉冲个数；以及所述根据所述加速度的关联参数值，执行与所述加速度的关联参数值相应的操作，包括：判断所述脉冲个数是否小于设定阈值；以及当所述脉冲个数小于所述设定阈值时，执行所述操作。
本公开的至少一个实施例还提供一种存储介质，在其上存储有计算机指令，其中，所述计算机指令被处理器运行时执行上述加速度处理方法中的一个或多个步骤。
本公开的至少一个实施例还提供一种电子设备，包括一个或多个处理器，所述处理器被配置为运行计算机指令以执行上述加速度处理方法中的一个或多个步骤。
附图说明
为了更清楚地说明本公开实施例的技术方案，下面将对实施例的附图作简单地介绍，显而易见地，下面描述中的附图仅仅涉及本公开的一些实施例，而非对本公开的限制。
图1为本公开一些实施例提供的加速度传感器的俯视图之一；
图2为本公开一些实施例提供的加速度传感器沿图1的A-A面剖开的剖面图；
图3A为本公开一些实施例提供的加速度传感器的俯视图之二；
图3B为本公开一些实施例提供的加速度传感器沿图3A的B-B面剖开的剖面图；
图4为本公开一些实施例提供的加速度传感器在加速度作用下的位移形变示意图；
图5A、图5B、图5C以及图5D为本公开一些实施例提供的加速度传感器的工作过程示意图；
图6A为本公开一些实施例提供的加速度传感器的电容器在加速度为零时的结构图；
图6B为本公开一些实施例提供的加速度传感器的电容器在加速度大于零时的结构图；
图7A为本公开一些实施例提供的加速度传感器的加速度与电容器的电容值之间的关系图；
图7B为一种叉指式加速度传感器的加速度与电容器的电容值之间的关系图；
图8为本公开一些实施例提供的电容检测电路的组成框图；
图9A为本公开一些实施例提供的电容检测电路的电路图之一；
图9B为本公开一些实施例提供的电容检测电路的电路图之二；
图10A为本公开一些实施例提供的第二电容器的充放电过程与检测信号之间的对应关系图之一；
图10B为本公开一些实施例提供的第二电容器的充放电过程与检测信号之间的对应关系图之二；
图11A为本公开一些实施例提供的加速度传感器的加速度与检测信号输出的高电平的次数之间的关系图之一；
图11B为本公开一些实施例提供的加速度传感器的加速度与检测信号输出的高电平的次数之间的关系图之二；
图11C为一种叉指式加速度传感器的加速度与检测信号输出的高电平的 次数之间的关系图；
图12为本公开一些实施例提供的电容检测方法的流程图；
图13为本公开一些实施例提供的加速度处理电路的组成框图；
图14为本公开一些实施例提供的加速度处理方法的流程图；
图15为本公开一些实施例提供的封装电路的示意图。
具体实施方式
下面将结合附图，对本公开实施例中的技术方案进行清楚、完整地描述，参考在附图中示出并在以下描述中详述的非限制性示例实施例，更加全面地说明本公开的示例实施例和它们的多种特征及有利细节。应注意的是，图中示出的特征不是必须按照比例绘制。所给出的示例仅旨在有利于理解本公开实施例的实施，以及进一步使本领域技术人员能够实施示例实施例。因而，这些示例不应被理解为对本公开的实施例的范围的限制。
除非另外特别定义，本公开使用的技术术语或者科学术语应当为本公开所属领域内具有一般技能的人士所理解的通常意义。本公开中使用的“第一”、“第二”以及类似的词语并不表示任何顺序、数量或者重要性，而只是用来区分不同的元器件。此外，在本公开各个实施例中，相同或类似的参考标号表示相同或类似的构件。本公开示例中的相邻层之间不一定紧密接触，可能存在一定的间隙。
在相关技术中，叉指式电容传感器是一种常用的微电子机械系统(MEMS)加速度传感器，叉指式MEMS加速度传感器包括可移动的检测质量块，在该检测质量块上设置有多根相互交叉的指状结构，以提高加速度传感器的灵敏度。但是，该指状结构需要占据很大的空间，不利于器件尺寸的小型化和集成化。另外，叉指式MEMS加速度传感器中，由于电容和叉指的距离成反比，因此两者呈非线性关系，不便于数据的计算和处理。叉指式MEMS加速度传感器对叉指的距离比较敏感，在不同的温度环境下，由于电极不可避免的出现热胀冷缩现象，会导致计算结果具有一定的偏差，即不同的环境温度，如不同季节和不同地区，叉指式MEMS加速度传感器对相同的加速度大小的检测结果差异性较大，受温度影响较大。
本公开实施例提出了一种加速度传感器、电容检测电路及方法、加速度 处理电路及方法、存储介质和电子设备。本公开实施例的加速度传感器、电容检测电路以及加速度处理电路可以应用在需要进行加速度检测的场景中。
本公开的实施例通过加速度传感器来将感知的加速度转化为电容器的电容值，且采用本公开实施例的加速度传感器转化得到的电容器的电容值与感知的加速度之间满足线性关系，因此便于数据计算、处理和监测。并且，本公开实施例的加速度传感器的体积小，便于集成，由于没有叉指结构而不易受温度影响。本公开实施例还通过电容检测电路来将加速度传感器感知的电容器的电容值进一步转化为便于检测和统计的检测信号(例如，方波信号)，从而可以迅速且灵敏地监测到电容器的电容值。本公开实施例的加速度处理电路还可以根据电容检测电路所输出的检测信号来控制汽车等交通运输工具执行安全措施，进而实现对驾驶员和乘客的人身安全进行保护。
例如，可以将本公开实施例的加速度传感器、电容检测电路以及加速度处理电路应用在车辆高速碰撞时的加速度检测。例如，通过本公开实施例提供的加速度传感器将车辆的加速度转化成与该加速度满足线性关系的电容器的电容值，再由电容检测电路来监测电容器的电容值，并将监测结果转化成方便处理的检测信号(例如，方波信号)，最后由加速度处理电路根据检测信号来确定车辆是否发生了碰撞以及碰撞的严重程度。
在一些实施例中，当碰撞不严重时(例如，通过检测电容值判断得到的加速度a小于某个设定的阈值)则不启动安全保护措施(例如，安全保护措施包括安全气囊)。
在另一些实施例中，当碰撞严重时(例如，通过检测电容值判断得到的加速度大于某个设定的阈值)，则需要启动安全保护措施(例如，启动安全气囊)。例如，电容检测电路可以将检测信号(例如，方波信号)发送给加速度计算子电路和处理子电路，再由加速度计算子电路和处理子电路来根据检测信号迅速确定汽车是否发生了碰撞以及是否应该启动安全保护措施(例如，启动安全气囊)。当判断车辆发生了严重碰撞后，车载电子控制单元ECU会向点火器发送命令，点火器响应于该命令进行点火。随后气体发生器会产生大量的气体(例如，氮气(N 2))，并将N 2输出至安全气囊来保护乘客人身安全。下面结合图1-图7B介绍本公开实施例的加速度传感器100。
如图1所示，本公开实施例提供一种加速度传感器100，该加速度传感器 100可以包括：底座101，固定于底座101之上的固定电极103，以及相对于固定电极103可移动的质量块102。质量块102包括移动部件1021和位于移动部件1021之上的导电电极104。导电电极104和固定电极103被配置为形成电容器，并且该电容器的电容可由于质量块102相对于底座101的移动而可变。例如，导电电极104的正投影与固定电极103的正投影的重叠面积可变。例如，固定电极103的正投影为该固定电极103沿垂直于底座101的方向在底座101表面上的投影，导电电极104的正投影为该导电电极104沿垂直于底座101的方向在底座101表面上的投影。在一些示例中，固定电极103位于导电电极104的上方或者下方，固定电极103的正投影与导电电极104的正投影相互重叠，且随着加速度传感器100的运动，该重叠面积由于质量块102与底座101的相对移动而可以发生变化。参考图1可知，在与底座101的表面垂直的方向上，导电电极104和固定电极103重叠，并且重叠面积可变。导电电极104和固定电极103被配置为形成电容器。该加速度传感器100的体积小，便于集成，由于没有叉指结构而不易受温度影响。
在一些实施例中，底座101可以为一个水平放置的基板(例如，该基板水平地固定于机动车中)，相应地，加速度传感器100用于感知水平方向上的加速度。此时，导电电极104和固定电极103在竖直方向上存在重叠且形成了重叠面积。例如，重叠面积可以包括图1虚线框示出的导电电极104所在的矩形区域。
需要说明的是，本公开实施例并不限定底座101的放置方向。例如，可以根据需要检测的加速度的方向来确定底座101的放置方向。
如图1所示，在一些示例中，移动部件1021上包括有一个矩形区域，并在这个矩形区域中设置与导电电极104对应的导电层。例如，该矩形区域可以包括：在加速度为0时，固定电极103在移动部件1021的表面上所形成的正投影的一部分，并且该正投影的一部分与移动部件1021相重合。例如，移动部件1021可以由较厚的硅单晶基片部分构成。
需要说明的是，本公开实施例并不限定质量块102中的移动部件1021和导电电极104的具体设置方式。例如，在一些示例中，导电电极104为一个单独的导电部件，且固定在移动部件1021上，移动部件1021由绝缘材料制作。例如，在另一些示例中，导电电极104嵌入在移动部件1021上，也即， 导电电极104与移动部件1021一体形成或者为移动部件1021的一部分，该移动部件1021由导电材料制作。移动部件1021和导电电极104还可以采用其他适用的设置方式，本公开的实施例对此不作限制。
此外，本公开实施例还可以通过设置多个加速度传感器100来感知多个不同方向的加速度。
为了进一步提高加速度传感器100所感知的加速度的灵敏性，在一些实施例中，在加速度传感器100所包括的固定电极103和导电电极104之间设置电介质层109。例如，电介质层109的材料可以包括但不限于石蜡、云母、钻石和聚酯等。
下面以图2为范例示例性介绍包含电介质层109的加速度传感器100。
图2为加速度传感器100沿图1的A-A面剖开的剖面图，且图2示出的加速度传感器100包括底座101、质量块102、电介质层109以及固定电极103，质量块102包括移动部件1021和导电电极104。例如，底座101、移动部件1021、导电电极104、电介质层109以及固定电极103由下至上依次设置。需要注意的是，图2示出的质量块102(或移动部件1021)与底座101之间并不是紧密接触的，这是为了使质量块102相对于底座101可平行移动。例如，质量块102与底座101之间的距离可以为0.5mm。例如，导电电极104也可以嵌入移动部件1021中。
在另外一些示例中，在加速度传感器100中，也可以使底座101、固定电极103、电介质层109、导电电极104以及移动部件1021由下至上依次设置，本公开的实施例在此不作限定。
本公开的上述实施例中，由于在固定电极103和导电电极104之间增加了电介质层109，因此可以有效提高由固定电极103和导电电极104构成的具有重叠面积的平板电容器的电容值。由于电容器的电容值增加，因此提高了加速度传感器100感知加速度的灵敏性。
在本公开的至少一个实施例中，为了将质量块102(或移动部件1021)固定于底座101上，并使质量块102在与底座101平行的第一方向(即加速度a所在的方向)发生一定位移，加速度传感器100还可以包括设置于底座101上的悬臂梁105，且质量块102(或移动部件1021)连接在悬臂梁105上。
如图1所示，通过悬臂梁105可以将质量块102连接在底座101上。例 如，可以将悬臂梁105的一端通过第一固定部件106与底座101连接，该悬臂梁105的另一端通过第二固定部件107连接于质量块102上。例如，可以采用微加工工艺堆积得到第一固定部件106。例如，第二固定部件107包括螺钉。
在一些实施例中，悬臂梁105包括弹簧或其它能够发生形变的弹性部件(例如，刚性悬臂梁)。例如，图1示出的加速度传感器100包括四根可发生一定弹性形变的悬臂梁105。本公开的实施例对悬臂梁105的数目不作限定。在一些示例中，采用弹簧作为悬臂梁105，则质量块102移动的距离的大小与弹簧的弹力相关。另外，采用弹簧作为悬臂梁105的加速度传感器100的体积相对较大，而采用刚性悬臂梁作为悬臂梁105的加速度传感器100的体积相对较小。
在一些实施例中，还通过固定部件108来将固定电极103的两端固定在底座101上。例如，可以采用微加工工艺堆积得到固定部件108。
例如，图1中的加速度传感器100还包括与固定电极103电连接的第一导线205，以及与导电电极104电连接的第二导线206。需要说明的是，本公开实施例并不限定第二导线206在质量块102上的设置位置，也就是说，第二导线206也可以设置于不同于图1的其他位置，只要保证第二导线206可以与导电电极104电连接即可。本公开实施例可以通过第一导线205和第二导线206来输出加速度传感器100中的电容器的电容值，以便电容检测电路将这个电容值转化为检测信号。
本公开实施例并不限定质量块102上设置的导电电极104的数量，相应的本公开实施例也不限定在底座101上固定的固定电极103的数量。通过设置多个导电电极104和多个固定电极103可以得到多个并联的平板电容器，进而提高加速度传感器100在感知加速度时的灵敏性。
如图3A所示，在加速度传感器100的质量块102的移动部件1021上平行且间隙地设置了n个导电电极104a……104n，相应的在底座101上平行且间隙地设置了n个固定电极103a……103n，其中n为大于1的整数。例如，n个导电电极104a……104n沿质量块102相对于底座101的移动方向平行排列，n个固定电极103a……103n也沿质量块102相对于底座101的移动方向平行排列，n个导电电极104a……104n与n个固定电极103a……103n一一 对应。
为了把n个固定电极103a……103n固定在底座101上，图3A还示出了将这些固定电极固定在底座101上的多个固定部件108a……108n。
图3B为加速度传感器100沿图3A的B-B切开的剖面图。从图3B可知，在每个导电电极104a……104n和每个固定电极103a……103n的两极板之间还分别设置了电介质层109。
在另外一些示例中，可以调整图3B中加速度传感器100的各层之间的位置关系。例如，在加速度传感器100中，可以使底座101、多个平行且间隙设置的固定电极103a……103n、与多个固定电极103a……103n相应设置的电介质层109、多个平行且间隙设置的导电电极104a……104n以及移动部件1021由下至上依次设置。
本公开上述实施例的加速度传感器100可以使得电容器的电容值与加速度传感器100所感知的加速度之间满足线性关系，下面将结合图4-图7B来说明两者之间的线性关系。
图1为加速度为0时加速度传感器100的示意图，图4为本公开实施例的加速度传感器100在加速度为a时的形变示意图。
图4的加速度传感器100在加速度a的作用下，使质量块102与底座101之间发生了相对位移，并使得导电电极104和固定电极103之间的重叠面积发生了变化(例如，图4中的导电电极104有部分区域移出了图1示出的矩形重叠区)。相应的，悬臂梁105与质量块102相连的一端也发生了一定形变。
为了说明图4相对于图1的形变量可以进一步参考图5A-图5D。在图5A与图5D中仅以刚性悬臂梁作为示范，推导了相关的计算公式，但这并不构成对本公开实施例的限制。
图5A中的加速度传感器100的加速度为0，且对应的电容器的初始电容值C0如图6A所示。图5C中的加速度传感器100的加速度为a，质量块102在加速度a的作用下相对于图5A的初始位置发生的位移为w，且此时加速度传感器100的电容器的电容值C如图6B所示。
结合上述图5A-5D可知，在加速度a的作用下，质量块102向左移动的距离为w。由于4根悬臂梁105各有一端与质量块102连接在一起，其移动距离同样是w。
根据图5A-图5D得到如下惯性力公式①和悬臂梁105的位移公式②：
4F＝ma      ①
Figure PCTCN2018112178-appb-000001
上述公式①中F表示单个悬臂梁105对质量块102的作用力(如图5B所示)，m表示质量块102的质量，a表示加速度传感器100的加速度。
上述公式②中的EI表示的是悬臂梁105的抗弯刚度，其中E表示悬臂梁105的弹性模量(即产生单位应变时所需的应力)，I表示悬臂梁105的材料横截面对弯曲中性轴的惯性矩；L表示悬臂梁105的长度(如图5B所示)。
假设在图6A中，固定电极103与导电电极104之间的重叠面积为S 0。在加速度a的作用下，当质量块102向左移动距离w后(即如图6B所示的情形)固定电极103与导电电极104之间的重叠面积变为了S。例如，由下面的公式③和公式⑤可知，加速度传感器100所形成的电容器的电容值C(或，C 0)和固定电极103与导电电极104之间的重叠面积S(或，S 0)这两者为正相关的线性关系。即，重叠面积S越大，电容值C越大。
根据上述参量，得到计算图6A的电容值C 0以及计算图6B的电容值C的公式分别如下：
Figure PCTCN2018112178-appb-000002
S 0＝eb      ④
Figure PCTCN2018112178-appb-000003
S＝(e-w)b      ⑥
上述公式③和公式⑤中的ε r表示电介质层109的介电常数，π表示圆周率，k表示静电常数，d表示固定电极103和导电电极104之间的电介质层109的厚度(如图6A所示)。上述公式④和⑥中的b表示质量块102的宽度(如图5A所示)，e表示固定电极103的宽度(如图5A所示)，w表示在加速度a的作用下质量块102相对于底座101发生的位移(如图5C和图5D所示)。
为了得到本公开实施例的加速度传感器100的加速度a与电容器的电容 值C的关系，可以联合上述公式①～⑥求解得到加速度a与电容值C的计算关系式如下：
Figure PCTCN2018112178-appb-000004
上述公式⑦中的参数K 1为常数，其大小为
Figure PCTCN2018112178-appb-000005
通过上述公式⑦可以看出，加速度传感器100的加速度a与电容值C之间满足线性关系(例如，负相关的线性关系)。即，电容值C越大，加速度a越小。因此，本公开实施例只需要监测出加速度传感器100的电容器的电容值C，就可以确定加速度a的大小。
图7A还给出了公式⑦中得到的加速度传感器100的加速度a与电容值C之间的函数关系图。从图7A可以直观的观察出，加速度a与电容值C之间满足线性关系(例如，负相关的关系)。从图7A还可以看出，当固定电极103和导电电极104之间的电容值为0时加速度a的大小为：a＝K 1；而当固定电极103和导电电极104之间的电容值增大为C 0时(此时电容值达到最大)，则加速度a减小为0。
图7B还提供了一种叉指式加速度传感器的加速度a与电容值C之间的关系图。从图7B可以看出，叉指式加速度传感器的加速度a与电容值C之间满足非线性(即曲线)关系。
可以理解的是，与图7A的线性关系相比，图7B的曲线关系不便于数据收集、处理和计算。因此，本公开实施例提供的加速度传感器100具有便于数据收集、处理和计算的技术效果。
下面结合图8-图11B介绍本公开实施例提供的电容检测电路200。
需要说明的是，本公开实施例的电容检测电路200既可以用于监测上述图1-图7A提供的加速度传感器100包括的电容器的电容值，也可以监测其它的电容类加速度传感器得到的电容值。例如，本公开实施例提供的电容检测电路200也可以用于监测叉指式加速度传感器的电容器的电容值。
本公开实施例通过电容检测电路200来监测加速度传感器包括的电容器的电容值，并将监测结果转化成方便处理的检测信号(例如，方波信号)。通过分析检测信号来得到加速度的关联参数值，可以提高监测加速度的灵敏度。
如图8所示，电容检测电路200可以用于监测上述加速度传感器100的电容器的电容值。图8所示的电容检测电路200包括：第一电容器C1和检测子电路202，其中，第一电容器C1的两端分别与加速度传感器100的固定电极103和导电电极104电气相连(例如，第一电容器C1的两个极板可以分别与第一导线205以及第二导线206相连)；检测子电路202被配置为将第一电容器C1的电容值转换为检测信号S1，并输出检测信号S1。在一些示例中，第一电容器C1的电容值等于加速度传感器100的电容器的电容值。例如，加速度传感器100中的固定电极103和导电电极104可以作为第一电容器C1的两个极板。
在一些实施例中，如图9A和图9B所示，检测子电路202可以包括：第一开关SW1、第二开关SW2、第三开关SW3、第二电容器C2、电阻R0、生成子电路2021以及存储子电路2022。例如，第一开关SW1、第二开关SW2和第三开关SW3可以为开关晶体管。
第一电容器C1被配置为：当第一开关SW1导通时进行充电；以及当第一开关SW1截止、第二开关SW2和第三开关SW3均导通时，进行放电并对第二电容器C2进行充电。
生成子电路2021被配置为根据第二电容器C2的电压和参考电压Vref，生成检测信号S1，其中，当第二电容器C2的电压低于参考电压Vref时，生成的检测信号S1处于第一电平，当第二电容器C2的电压不低于参考电压Vref时，生成的检测信号S1处于第二电平。在一些示例中，第一电平是比第二电平低的电压信号。例如，第一电平为方波信号的低电平，第二电平为该方波信号的高电平。
第二电容器C2被配置为在检测信号S1处于第二电平(例如，高电平)时，通过电阻R0进行放电。例如，当检测信号S1处于高电平时通过开关单元来控制第二电容器C2放电。
需要说明的是，第二电容器C2的电容值小于第一电容器C1的电容值。参考电压Vref可以设置的较小，以使第二电容器C2较快的完成放电过程。
存储子电路2022被配置为缓存并输出检测信号S1。
本公开实施例在第一电压V dd的作用下使第一电容器C1充电，之后再通过第二电容器C2的放电次数来测量第一电容器C1上所存储的电荷量，进而 判断出第一电容器C1的电容值的大小。因此采用本公开实施例提供的电容检测电路200可以有效提高电容值检测的灵敏性以及速度。
如图9A所示，在一些实施例中，检测子电路202还包括：第一反相器B1，被配置为将时钟信号端输入的时钟信号CLK反相并输出至第一开关SW1的控制极；以及第二反相器B2，被配置将检测信号S1反相并输出至第三开关SW3的控制极，使得当检测信号S1处于第一电平(例如，低电平)时，第三开关SW3导通。
通过以上记载可知，本公开实施例通过时钟信号CLK来控制第一开关SW1的导通或截止，并通过检测信号S1来控制第三开关SW3的导通或截止。
如图9A所示，检测子电路202还包括：第四开关SW4，被配置为在检测信号S1处于第二电平(例如，高电平)时导通，使得第二电容器C2通过电阻R0放电。
如图9A所示，第一反相器B1的输入端与时钟信号端连接以接收时钟信号CLK，第一反相器B1的输出端与第一开关SW1的控制极连接；第二反相器B2的输入端与生成子电路2021的输出端连接，第二反相器B2的输出端与第三开关SW3的控制极连接；第一开关SW1的第一极与第一电源端连接以接收输入的第一电压V dd，第二极与第一电容器C1的第一端连接；第一电容器C1的第二端接地；第二开关SW2的控制极与所述时钟信号端连接以接收时钟信号CLK，第一极与第一电容器C1的第一端连接，第二极与第二电容器C2的第一端连接；第三开关SW3的第一极与第二电容器C2的第二端连接，第二极与第一电容器C1的第二端连接；以及第四开关SW4的控制极与生成子电路2021的输出端连接，第一极与电阻R0的第一端连接，第二极与第二电容器C2的第二端连接。
如图9A所示，生成子电路2021可以包括比较器；比较器的正相输入端分别与第二电容器C2的第一端和电阻R0的第二端连接，反相输入端与参考电压端连接以接收参考电压Vref，输出端与第二反相器B2的输入端连接。
如图9A所示，存储子电路2022包括锁存器，该锁存器的输入端与生成子电路2021的输出端连接，该锁存器的输出端作为电容检测电路200的输出端。
图9B与图9A的检测子电路202的区别为：在图9B中通过两路时钟信 号(即第一时钟信号CLK1和第二时钟信号CLK2)来分别控制第一开关SW1和第二开关SW2的导通和截止，进而可以省略图9A示出的第一反相器B1。例如，图9B所示的第一开关SW1的控制极与第一时钟信号端连接以接收输入的第一时钟信号CLK1，第二开关SW2的控制极与第二时钟信号端连接以接收输入的第二时钟信号CLK2。需要说明的是，第一时钟信号CLK1和第二时钟信号CLK2为反相信号。
图9B的生成子电路2021也可以包括比较器，且比较器的连接方式可以参考图9A。图9B的存储子电路2022也可以包括锁存器，且该锁存器的具体连接可以参考图9A。图9B的其他电路元件不再一一赘述，相关内容可参考图9B所示内容或者参考上述针对图9A的解释说明。
图9A和图9B示出的电容检测电路200生成和输出的检测信号S1包括方波信号，且方波信号的脉冲个数与加速度传感器100的加速度为线性关系。
下面结合图9A来说明电容检测电路200的工作过程，并结合工作过程来进一步阐述方波个数与加速度传感器100的加速度为线性关系的结论。在描述电容检测电路200的工作过程时，假设图9A的第一开关SW1、第二开关SW2、第三开关SW3以及第四开关SW4均为高电平导通的晶体管(例如，N型晶体管)。需要说明的是，本公开实施例并不限定上述四个开关单元必须为高电平导通。例如，第一开关SW1、第二开关SW2、第三开关SW3以及第四开关SW4中的一个或多个开关也可以采用低电平导通的晶体管(例如，P型晶体管)。
第一步，将图9A的时钟信号CLK置低，相应的第一开关SW1导通(闭合)，第二开关SW2截止(断开)，此时第一电压V dd对第一电容器C1快速充电。当第一电容器C1的充电电压达到第一电压V dd后，将时钟信号CLK置高。第二步，由于时钟信号CLK置高，则第一开关SW1断开且第二开关SW2闭合，第一电容器C1上的电荷向第二电容器C2充电。当第二电容器C2的电压达到参考电压V ref时，比较器输出高电平脉冲，该高电平脉冲传送至锁存器中进行锁存。同时，比较器输出高电平脉冲还使第三开关SW3截止，使第四开关SW4导通，之后第二电容器C2会对电阻R 0放电。重复以上第二步过程，直到第一电容器C1的电荷全部释放。
上述工作过程也可以用如下表格来表示，在下述表格中用数字“1”表示 第一开关SW1、第二开关SW2、第三开关SW3以及第四开关SW4的控制极与高电平相连，用数字“0”表示第一开关SW1、第二开关SW2、第三开关SW3以及第四开关SW4的控制极与低电平相连。例如，对于第二开关SW2表格中的数字“1”表示时钟信号CLK为高电平，数字“0”表示时钟信号CLK为低电平；对于第四开关SW4表格中的数字“1”表示检测信号S1处于高电平，数字“0”表示检测信号S1为低电平。
Figure PCTCN2018112178-appb-000006
结合上述工作过程，根据电荷守恒定律，可以得到如下公式：
CV dd＝NC intV ref
故有：
Figure PCTCN2018112178-appb-000007
上述公式⑧中的N表示检测信号S1输出的第二电平(即高电平)的次数，也表示第二电容器C2的放电次数(可以参考后续图10A或图10B)；C表示第一电容器C1的电容值，Cint表示第二电容器C2的电容值。
通过上述公式⑧可以看出存储子电路2022中的锁存器输出的检测信号S1中的高电平(即第二电平)的次数N与第一电容器C1的电容值C满足线性正相关关系。因此，在本公开实施例中，可以通过统计检测信号S1中的高电平次数N来直接确定第一电容器C1的电容值的相对大小。
图10A和图10B提供了与上述图9A的工作过程相应的第二电容器C2的充放电过程图以及检测信号S1的波形图。例如，图10A和图10B为加速度传感器100在不同加速度a下，电容检测电路200所输出的检测信号S1的波形图及第二电容器C2的充放电过程图。图10A为较大加速度情况下的 检测信号S1的波形示意图以及第二电容器C2的充放电过程图，而图10B为较小加速度情况下的检测信号S1的波形示意图以及第二电容器C2的充放电过程图。
从图10A和图10B可以看出，第二电容器C2充电时，检测信号S1输出低电平信号；第二电容器C2放电时，检测信号S1输出高电平信号。因此，检测信号S1中出现的高电平次数与第二电容器C2的放电次数相等。例如，在图10A和图10B中，当第二电容器C2的电压V2经充电升高至参考电压Vref时，第二电容器C2开始放电过程，在放电过程中相应的检测信号S1输出高电平。
另外，对比图10A和图10B还可以发现，加速度传感器100的加速度越大则存储子电路2022中的锁存器输出的高电平的次数N就越少。这是由于：加速度传感器100的加速度a越大，则加速度传感器100中的质量块102的位移越大，从而加速度传感器100的电容器的电容值越小(第一电容器C1的电容值C也越小)。如果加速度传感器100的电容器的电容值越小，则其对第二电容器C2的充电速度越慢，相应的存储子电路2022中的锁存器所输出的检测信号S1的波形的频率越低，即相同时间段内存储子电路2022中的锁存器输出的高电平的次数N也越少。
下面进一步阐述加速度传感器100所感知的加速度a与检测信号S1输出的高电平(即第二电平)的次数N之间的计算关系式：
根据上述公式⑦和⑧，有：
Figure PCTCN2018112178-appb-000008
上述公式⑨中的参数K 1为常数，具体为：
Figure PCTCN2018112178-appb-000009
上述公式⑨中的参数K 2为常数，具体为
Figure PCTCN2018112178-appb-000010
结合上述公式⑨可以得到加速度传感器100感知的加速度a和存储子电路2022中的锁存器输出的检测信号S1中的高电平的次数N之间关系如图11A所示。
从图11A可以看出，加速度传感器100所感知的加速度a与检测信号S1 中的高电平的输出次数N满足线性关系。或者说，加速度a与第二电容器C2的放电次数满足线性关系。
另外，从图11A还可以看出，当加速度a的值为K 1时，相应的高电平输出次数N为0；当加速度a减小到0时，则高电平输出次数N增大为参数K 2的值。也就是说，加速度传感器100所感知的加速度a与检测信号S1中的高电平的输出次数N满足线性负相关的关系。
例如，在至少一个实施例中，可以利用加速度a与检测信号S1所包含的高电平输出次数N之间的线性负相关的关系来监测汽车是否发生了碰撞。例如，参考图11B，如果已知汽车在发生碰撞时其加速度大于最大加速度阈值a max，本公开实施例可以利用上述公式⑨求解得出与该最大加速度阈值a max相对应的检测信号S1输出的高电平次数Nmin。之后，当判断得到检测信号S1输出的高电平次数N小于或等于Nmin时，就可以直接得出汽车发生了碰撞。
本公开实施例通过分析电容检测电路200所输出的检测信号S1中包含的高电平次数N，就可以直接判断电容值的大小(或者进一步判断出加速度的大小)，计算量得到减小并提高了处理速度。
需要说明的是，本公开实施例并不限定电容检测电路200只可以和本公开实施例的加速度传感器100来配合使用。例如，也可以将叉指式加速度传感器与本公开实施例的电容检测电路200来配合使用。例如，图11C为将叉指式加速度传感器与本公开实施例的电容检测电路200配合时，得到的加速度a与高电平输出次数N之间的关系图。从图11C可以看出，当采用叉指式加速度传感器时，加速度a与高电平输出次数N之间满足非线性(即曲线)关系。如果采用叉指式加速度传感器和电容检测电路200来配合，也可以实现通过统计检测信号S1中的高电平次数N来判断加速度a的大小。
下面结合图12来介绍本公开至少一个实施例提供的电容检测方法300，该电容检测方法300可以用于上述至少一个实施例中的电容检测电路200。
如图12所示，电容检测方法300包括：步骤S301，对第一电容器C1进行充电；步骤S302，重复充放电操作直至第一电容器C1的电荷释放完毕，其中，该充放电操作包括：通过对第一电容器C1进行放电，实现对第二电容器C2进行充电；以及对第二电容器C2进行放电；步骤S303，根据第二 电容器C2的电压(例如，图9A和9B所示的电压V2)和参考电压Vref，生成检测信号S1，其中，当第二电容器C2的电压低于参考电压Vref时，生成的检测信号S1处于第一电平，当第二电容器C2的电压不低于参考电压Vref时，生成的检测信号S1处于第二电平；以及步骤S304，缓存并输出检测信号S1。例如，第一电平为方波信号的低电平，第二电平为方波信号的高电平。
对于上述步骤S301、S302以及S303中所涉及的处理细节可以参考针对上述电容检测电路200的相关描述，在此不做赘述。
本公开至少一个实施例还提供一种加速度处理电路400，该加速度处理电路400可以与上述实施例记载的加速度传感器100相连。对于加速度传感器100的结构可以参考图1-图7A的描述，在此不做赘述。
如图13所示，加速度处理电路400包括上述的电容检测电路200、加速度计算子电路401和处理子电路402，其中，电容检测电路200被配置为输出检测信号S1至加速度计算子电路401；加速度计算子401电路被配置为根据检测信号S1，计算加速度的关联参数值；以及处理子电路402被配置为根据加速度的关联参数值，执行与所述加速度的关联参数值相应的操作(例如机动车的安全保护措施)。例如，加速度处理电路400还可以包括加速度传感器100。
在一些实施例中，上述关联参数值与加速度传感器测得的加速度为线性关系。例如，检测信号S1包括方波信号，关联参数值包括方波信号的脉冲个数(例如，上述高电平输出次数N)。
在一些实施例中，电容检测电路200输出的检测信号S1为方波信号，且处理子电路402被配置为当该方波信号的脉冲个数小于设定阈值(例如图11B所示的Nmin为设定阈值)时，执行安全保护措施。例如，安全保护措施包括：打开安全气囊、拨打报警电话、发出提示信息或者生成警示信号(例如，生成警示信号可以包括启动汽车双闪信号等)。
另外，上述加速度处理电路400所包含的电容检测电路200具体可以参考针对图8-图9B的描述，在此不做赘述。
在一些示例中，可以采用上述加速度处理电路400来判断汽车是否发生了碰撞。
在本公开的实施例中，加速度处理电路400可以根据加速度的关联参数值来快速判断加速度是否超过安全阈值，从而及时启动安全保护措施，有效保障了司机和乘客的人身安全。
本公开的至少一个实施例还提供一种加速度处理方法500，该加速度处理方法500可以用于加速度处理电路400。
如图14所示，加速度处理方法500可以包括：步骤S501，监测加速度传感器100中的电容器并将监测结果转换为检测信号S1；步骤S502，根据检测信号S1，计算加速度的关联参数值；以及步骤S503，根据加速度的关联参数值，执行相应的安全保护措施。
在一些实施例中，检测信号S1为方波信号。相应的，步骤S502包括：在预定时间段内，统计该方波信号的脉冲个数，且步骤S503包括：判断脉冲个数是否小于设定阈值；以及当脉冲个数小于设定阈值时，执行安全保护措施。例如，设定阈值可以为图11B所示的Nmin。
例如，安全保护措施包括：打开安全气囊、拨打报警电话、发出提示信息或者生成警示信号(例如，警示信号可以包括双闪信号等)。
如图15所示，本公开实施例还提供一种封装加速度传感器100和电容检测电路200的结构。
加速度传感器100可以为基于微电子机械系统(MEMS)的加速度传感器，也就是说，本公开实施例可以通过微加工工艺在硅片1530上加工形成惯性测量元件(即加速度传感器100)。本公开实施例还基于专用集成电路(ASIC)来构造电容检测电路200。由于微加工工艺和专用集成电路(ASIC)采用相似的工艺，因此可以将加速度传感器100和电容检测电路200集成在封装基板1510和印刷电路板1500之上。例如，可以采用微加工工艺技术制造加速度传感器100，并利用专用集成电路(ASIC)工艺技术制造电容检测电路200，然后再将两者粘在同一个封装盒1503内(如图15所示)。
在一些示例中，如图15所示，还可以采用盖帽1520来保护加速度传感器100。
为了使加速度传感器100和电容检测电路200互连，在图15中还示出了与加速度传感器100的固定电极103电连接的第一导线205以及与导电电极104电连接的第二导线206。
需要说明的是，本公开上述实施例的加速度处理电路400也可以基于专用集成电路(ASIC)来构造，因此也可以将图15中示出的电容检测电路200替换为加速度处理电路400。最终实现将加速度传感器100和加速度处理电路400封装在一起的目的。
本公开实施例将加速度传感器100和电容检测电路200(或加速度处理电路400)参照图15进行封装，可以提高整个设备的稳定性。
本公开的至少一个实施例还提供一种存储介质，在其上存储有计算机指令，其中，所述计算机指令被处理器运行时执行加速度处理方法500中的一个或多个步骤。
例如，存储介质可以包括一个或多个计算机程序产品的任意组合，计算机程序产品可以包括各种形式的计算机可读存储器，例如易失性存储器和/或非易失性存储器。易失性存储器例如可以包括随机存取存储器(RAM)和/或高速缓冲存储器(cache)等。非易失性存储器例如可以包括只读存储器(ROM)、硬盘、可擦除可编程只读存储器(EPROM)、便携式紧致盘只读存储器(CD-ROM)、USB存储器、闪存等。在存储介质上可以存储一个或多个计算机程序模块，当该一个或多个计算机程序模块被运行时，可以实现加速度处理方法500中的一个或多个步骤。在存储介质中还可以存储各种应用程序和各种数据以及应用程序使用和/或产生的各种数据等。
本公开的至少一个实施例还提供一种电子设备，包括一个或多个处理器，所述处理器被配置为运行计算机指令以执行加速度处理方法500中的一个或多个步骤。
例如，处理器可以是中央处理单元(CPU)、数字信号处理器(DSP)或者具有数据处理能力和/或程序执行能力的其它形式的处理单元，例如现场可编程门阵列(FPGA)等；例如，中央处理单元(CPU)可以为X86或ARM架构等。处理器可以为通用处理器或专用处理器，可以运行计算机指令以执行加速度处理方法500中的一个或多个步骤。
以上所述，仅为本公开的具体实施方式，但本公开的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本公开揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本公开的保护范围之内。因此，本公开的保护范围应以所述权利要求的保护范围为准。

Claims (26)

  1. 一种加速度传感器，包括：
    底座；
    固定于所述底座之上的固定电极；以及
    相对于所述固定电极可移动的质量块；
    其中，所述质量块包括导电电极，所述导电电极与所述固定电极被配置为形成电容器，并且所述电容器的电容可由于所述质量块相对于所述底座的移动而可变。
  2. 如权利要求1所述的加速度传感器，还包括位于所述导电电极和所述固定电极之间的电介质层。
  3. 如权利要求1或2所述的加速度传感器，还包括位于所述底座上的悬臂梁，所述质量块连接在所述悬臂梁上。
  4. 如权利要求3所述的加速度传感器，其中，所述悬臂梁的一端与所述底座连接，所述悬臂梁的另一端与所述质量块连接。
  5. 如权利要求4所述的加速度传感器，其中，所述悬臂梁包括弹簧。
  6. 如权利要求1-5任一项所述的加速度传感器，其中，所述电容器的电容值与所述加速度传感器测得的加速度为线性关系。
  7. 如权利要求1-5任一项所述的加速度传感器，其中，所述固定电极为多个，多个所述固定电极在所述底座上间隙分布。
  8. 如权利要求7所述的加速度传感器，其中，多个所述固定电极沿所述质量块相对于所述底座的移动方向平行排列。
  9. 一种电容检测电路，用于监测如权利要求1-8任一项所述的加速度传感器的电容器的电容值，包括：第一电容器和检测子电路；其中，
    所述第一电容器的两端分别与所述加速度传感器的固定电极和导电电极电气相连；以及
    所述检测子电路被配置为将所述第一电容器的电容值转换为检测信号，并输出所述检测信号。
  10. 如权利要求9所述的电容检测电路，其中，所述检测子电路包括：第一开关、第二开关、第三开关、第二电容器、电阻、生成子电路以及存储 子电路；其中，
    所述第一电容器被配置为：
    响应于所述第一开关导通时进行充电；以及
    响应于所述第一开关截止、所述第二开关和所述第三开关均导通进行放电并对所述第二电容器进行充电；
    所述生成子电路被配置为根据所述第二电容器的电压和参考电压，生成所述检测信号，其中，当所述第二电容器的电压低于所述参考电压时，生成的所述检测信号处于第一电平，当所述第二电容器的电压不低于所述参考电压时，生成的所述检测信号处于第二电平；
    所述第二电容器被配置为响应于所述检测信号处于所述第二电平，通过所述电阻进行放电；以及
    所述存储子电路被配置为缓存并输出所述检测信号。
  11. 如权利要求10所述的电容检测电路，其中，所述检测子电路还包括：
    第一反相器，被配置为将时钟信号端输入的时钟信号反相并输出至所述第一开关的控制极；以及
    第二反相器，被配置为将所述检测信号反相并输出至所述第三开关的控制极，使得当所述检测信号处于所述第一电平时，所述第三开关导通。
  12. 如权利要求11所述的电容检测电路，其中，所述检测子电路还包括：
    第四开关，被配置为响应于所述检测信号处于所述第二电平而导通，使得所述第二电容器通过所述电阻放电。
  13. 如权利要求12所述的电容检测电路，其中，
    所述第一反相器的输入端与所述时钟信号端连接，所述第一反相器的输出端与所述第一开关的控制极连接；
    所述第二反相器的输入端与所述生成子电路的输出端连接，所述第二反相器的输出端与所述第三开关的控制极连接；
    所述第一开关的第一极与第一电源端连接以接收输入的第一电压，所述第一开关的第二极与所述第一电容器的第一端连接；
    所述第一电容器的第二端接地；
    所述第二开关的控制极与所述时钟信号端连接以接收所述时钟信号，所 述第二开关的第一极与所述第一电容器的第一端连接，所述第二开关的第二极与所述第二电容器的第一端连接；
    所述第三开关的第一极与所述第二电容器的第二端连接，所述第三开关的第二极与所述第一电容器的第二端连接；以及
    所述第四开关的控制极与所述生成子电路的输出端连接，所述第四开关的第一极与所述电阻的第一端连接，所述第四开关的第二极与所述第二电容器的第二端连接。
  14. 如权利要求13所述的电容检测电路，其中，
    所述生成子电路包括比较器；
    所述比较器的正相输入端分别与所述第二电容器的第一端和所述电阻的第二端连接，所述比较器的反相输入端与参考电压端连接以接收所述参考电压，所述比较器的输出端与所述第二反相器的输入端连接。
  15. 如权利要求10-14任一项所述的电容检测电路，其中，所述存储子电路包括锁存器，所述锁存器的输入端与所述生成子电路的输出端连接。
  16. 如权利要求9-14任一项所述的电容检测电路，其中，所述检测信号包括方波信号，所述方波信号的脉冲个数与所述加速度传感器的加速度为线性关系。
  17. 一种用于权利要求9-16任一项所述的电容检测电路的电容检测方法，包括：
    对所述第一电容器进行充电；
    重复充放电操作直至所述第一电容器的电荷释放完毕，其中，所述充放电操作包括：通过对所述第一电容器进行放电，实现对第二电容器进行充电；以及对所述第二电容器进行放电；
    根据所述第二电容器的电压和参考电压，生成所述检测信号，其中，当所述第二电容器的电压低于所述参考电压时，生成的所述检测信号处于第一电平，当所述第二电容器的电压不低于所述参考电压时，生成的所述检测信号处于第二电平；以及
    缓存并输出所述检测信号。
  18. 一种加速度处理电路，包括如权利要求9-16任一项所述的电容检测电路、加速度计算子电路和处理子电路；其中，
    所述电容检测电路被配置为输出所述检测信号至所述加速度计算子电路；
    所述加速度计算子电路被配置为根据所述检测信号，计算加速度的关联参数值；以及
    所述处理子电路被配置为根据所述加速度的关联参数值，执行与所述加速度的关联参数值相应的操作。
  19. 如权利要求18所述的加速度处理电路，其中，所述关联参数值与所述加速度传感器测得的加速度为线性关系。
  20. 如权利要求19所述的加速度处理电路，其中，所述检测信号包括方波信号，所述关联参数值包括所述方波信号的脉冲个数。
  21. 如权利要求20所述的加速度处理电路，其中，所述处理子电路被配置为当所述方波信号的脉冲个数小于设定阈值时，执行所述操作。
  22. 如权利要求18-21任一项所述的加速度处理电路，其中，所述操作包括：打开安全气囊、拨打报警电话、发出提示信息或者生成警示信号。
  23. 一种用于权利要求18-22任一项所述的加速度处理电路的加速度处理方法，包括：
    监测所述加速度传感器中的电容器并将监测结果转换为所述检测信号；
    根据所述检测信号，计算所述加速度的关联参数值；以及
    根据所述加速度的关联参数值，执行与所述加速度的关联参数值相应的操作。
  24. 如权利要求23所述的加速度处理方法，其中，
    所述检测信号为方波信号；
    所述根据所述检测信号，计算所述加速度的关联参数值，包括：在预定时间段内，统计所述方波信号的脉冲个数；以及
    所述根据所述加速度的关联参数值，执行与所述加速度的关联参数值相应的操作，包括：
    判断所述脉冲个数是否小于设定阈值；以及
    当所述脉冲个数小于所述设定阈值时，执行所述操作。
  25. 一种存储介质，在其上存储有计算机指令，其中，所述计算机指令被处理器运行时执行权利要求23或24所述的加速度处理方法的一个或多个 步骤。
  26. 一种电子设备，包括一个或多个处理器，所述处理器被配置为运行计算机指令以执行权利要求23或24所述的加速度处理方法的一个或多个步骤。
PCT/CN2018/112178 2018-03-14 2018-10-26 加速度传感器、电容检测电路及方法、加速度处理电路及方法、存储介质和电子设备 WO2019174243A1 (zh)

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