CN109668675A

CN109668675A - A kind of MEMS integrates the device of baroceptor doubleway output

Info

Publication number: CN109668675A
Application number: CN201910030831.6A
Authority: CN
Inventors: 郝秀春; 陈忠位; 李宇翔; 蒋纬涵
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2019-01-14
Filing date: 2019-01-14
Publication date: 2019-04-23

Abstract

The invention discloses a dual output device of a MEMS integrated air pressure sensor. A capacitance-to-digital conversion module is connected with a MEMS sensitive element, and the capacitance signal is directly converted into a digital signal and transmitted to a main control module. The main control module is based on the capacitance of the sensitive element. The relationship with the air pressure converts the capacitance value into the air pressure value, which is packaged into a frame and output through the serial port module. The DA conversion module communicates with the main control module, and the calibrated air pressure value is linearly converted into a voltage output through the MCU. Compared with the prior art, the advantages and beneficial effects are as follows: it can measure three micro-capacitors at one time; after being processed by the MCU, both the analog output and the digital output are directly related to the air pressure, and there is no need for secondary processing; there are two types of analog and digital The output is more applicable and can be applied to a variety of occasions.

Description

A kind of MEMS integrates the device of baroceptor doubleway output

Technical field

The invention belongs to the technical fields of integrated silicon capacitance MEMS pressure sensor output capacitance measurement, more particularly to A kind of device of the integrated analog- and digital- doubleway output of silicon capacitance MEMS pressure sensor, this method are applied to integrated pressure Measurement of the sensor to pressure environment.

Background technique

MEMS integrates baroceptor and is integrated with the absolute pressure formula and a kind of totally three kinds of changes of differential pressure type of two kinds of different measurement ranges Pole span formula pressure sensor.Due to silicon capacitance MEMS pressure sensor volume very little, the capacitance change of output is very small, And there are biggish parasitic capacitances.Therefore it needs to detect extremely small capacitor in the case where parasitic capacitance is relatively large and become Change amount, this special detection demand propose very high requirement to the design of high accuracy capacitive readout circuit.

Small capacitance detection method common at present has resonance circuit, oscillating circuit, AC bridge circuit, switching capacity inspection The dedicated capacitance detecting integrated circuit such as slowdown monitoring circuit and charge and discharge power detection circuit, the Common advantages of above-mentioned detection method are flexible designs Property high, the circuit that selection can be required applicable according to sensor measurement；The disadvantage is that circuit design is relative complex, parasitic capacitance it is larger and Single channel capacitor can only be measured.General capacitance detecting integrated circuit is also widely used, such as PCAP02, AD7746 capacitor number turn The convert of capacitor to voltage chip such as chip and CAV444, CAV424 is changed, relative to dedicated capacitance detecting integrated circuit, universal collection Simple at circuit peripheral circuit, volume is smaller, and stray capacitance is relatively small.

Summary of the invention

Based on the above deficiency, the present invention discloses a kind of device of integrated baroceptor doubleway output of MEMS, is capable of providing Analog- and digital- two kinds of way of outputs, improve the applicability of sensor；Circuit design is simple, and parasitic capacitance is small.It can be simultaneously Three-way sensor is measured, the volume of measuring circuit is reduced down to a certain degree and reduces the influence of stray capacitance.Practical work In Cheng Yingyong, need to select the output type of sensor according to project demands.Sensor with numeral output and simulation output With more widely applicability.It include multiple sensors since MEMS integrates baroceptor, and baroceptor needs to demarcate The measured value and atmospheric pressure value that capacitor can just be made correspond.In the case where guaranteeing the accurate situation of multiple sensor measurement result by its turn Corresponding atmospheric pressure value is turned to, additionally needs to provide analog- and digital- output.In view of MEMS integrates the applied field of baroceptor It closes, it is necessary to which the volume for reducing sensor to the greatest extent realizes that above-mentioned function is very difficult.

The specific technical solution that the present invention uses is as follows:

A kind of MEMS integrates the device of baroceptor doubleway output, including MEMS sensing element, capacitor number modulus of conversion Block, D/A conversion module, serial port module and main control module；MEMS sensing element is connect with capacitor data-converting block, master control mould Block is connect with D/A conversion module, capacitor data-converting block and serial port module respectively；

The capacitor data-converting block is connect with MEMS sensing element, and capacitance signal is converted into digital signal Send main control module to, capacitance is converted to air pressure according to the relationship of sensing element capacitor and air pressure by the main control module Value is exported by serial port module after encapsulating framing, communicates between the D/A conversion module and main control module, will be marked by MCU Atmospheric pressure value after fixed is linearly converted to voltage output.

Further, the capacitor data-converting block selects PCAP02 chip, and chip is connect with MEMS sensing element, with Pass through IIC protocol communication between main control module.

Further, the main control module selects STM32.

Further, the serial port module selects MAX232 electrical level transferring chip, and the TTL signal of main control module output is turned Turn to the RS232 signal output of standard.

Further, the D/A conversion module selects 12 high speed serialization DA chip TLV5618 of two-way, has two-way DA defeated Out, absolute pressure formula and the intermediate fixed DA all the way that shares are exported, and another way DA output is used for differential pressure type.

A kind of MEMS of the present invention integrates the device of the analog- and digital- doubleway output of baroceptor, with the prior art Be compared to advantage and beneficial effect: biggest advantage is that circuit parasitic capacitance is small, being capable of three road small capacitance of one-shot measurement；Through After MCU processing, simulation output and numeral output are all directly related to air pressure, no longer need to carry out secondary treatment；Have analog- and digital- Two kinds of output has more applicability, can be applied to a variety of occasions.

Include multiple sensors since MEMS integrates baroceptor in the present invention, and baroceptor needs to demarcate ability The measured value and atmospheric pressure value for making capacitor correspond.It is translated into the case where guaranteeing the accurate situation of multiple sensor measurement result Corresponding atmospheric pressure value additionally needs to provide analog- and digital- output.It, must in view of MEMS integrates the application of baroceptor The volume of sensor must be reduced to the greatest extent, apparatus of the present invention are simple, versatile, and detection accuracy is high, be just able to solve it is above-mentioned go out Existing problem.

Detailed description of the invention

Above-mentioned and/or additional aspect of the invention and advantage will become from the description of the embodiment in conjunction with the following figures Obviously and it is readily appreciated that, in which:

Fig. 1 is the apparatus system block diagram that a kind of MEMS provided in an embodiment of the present invention integrates baroceptor doubleway output.

Fig. 2 is the schematic diagram of device that a kind of MEMS provided in an embodiment of the present invention integrates baroceptor doubleway output.

Fig. 3 is the program of device process that a kind of MEMS provided in an embodiment of the present invention integrates baroceptor doubleway output Figure.

Specific embodiment

The embodiment of the present invention is described below in detail, examples of the embodiments are shown in the accompanying drawings, wherein from beginning to end Same or similar label indicates same or similar element or element with the same or similar functions.Below with reference to attached The embodiment of figure description is exemplary, and for explaining only the invention, and is not considered as limiting the invention.

Referring to FIG. 1, a kind of MEMS of the present invention integrates the device of baroceptor doubleway output by MEMS sensitivity Element, capacitor data-converting block, D/A conversion module, serial port module and main control module are constituted.The capacitor number modulus of conversion The signal of MEMS sensing element is sent into main control module by block, and then main control module passes through D/A conversion module respectively and serial port module is defeated Analog and digital signal out.

Preferably, the capacitor digital module uses PCAP02, and it is at low cost, multichannel capacitance signal, sampling speed can be read Rate and resolution ratio all meet system requirements.

Referring to FIG. 2, a kind of MEMS of the present invention integrates the device of baroceptor doubleway output, PCAP02's 29,30,31,32 and 3,4 pins reserve the interface of MEMS sensing element, and IIC communicates 11 and 13 pins of pin 19 and 21 and MCU Connection；The SPI communication port 1,2,3 of TLV5618 is connected with 18,19,20 pins of MCU respectively；11 and 12 pins of MAX232 It is connect respectively with the port UART of MCU 8,9.

With reference to Fig. 3, a kind of device of the integrated baroceptor doubleway output of MEMS of the present invention, specific detection process Be: when air pressure changes, PCAP02 acquires the capacitance of No. three sensing elements and transfers data to MCU by IIC. There is the calibration value of sensing element capacitor Yu air pressure corresponding relationship in MCU.After data processing, MCU is by each sensor Capacitance is converted to corresponding atmospheric pressure value, and data-signal encapsulation framing becomes standard after the level conversion of serial port module RS232 signal；In addition, MCU can be communicated by SPI with TLV5618, DA measures air pressure correspondence for exporting differential pressure pick-up all the way Voltage value, another way DA output then need to judge that air pressure at this time belong to the survey of absolute pressure formula or intermediate fixed sensor by MCU Range is measured, and exports corresponding voltage value.

Embodiments of the present invention are explained in detail above in conjunction with attached drawing, but the present invention is not limited to above-mentioned implementations Mode within the knowledge of a person skilled in the art can also be without departing from the purpose of the present invention It makes a variety of changes.

In the description of this specification, reference term " one embodiment ", " some embodiments ", " illustrative examples ", The description of " example ", " specific example " or " some examples " etc. means specific features described in conjunction with this embodiment or example, knot Structure, material or feature are included at least one embodiment or example of the invention.In the present specification, to above-mentioned term Schematic representation may not refer to the same embodiment or example.Moreover, specific features, structure, material or the spy of description Point can be combined in any suitable manner in any one or more of the embodiments or examples.

Although an embodiment of the present invention has been shown and described, it will be understood by those skilled in the art that: not A variety of change, modification, replacement and modification can be carried out to these embodiments in the case where being detached from the principle of the present invention and objective, this The range of invention is defined by the claims and their equivalents.

Claims

1. a device of MEMS integrated air pressure sensor dual output, it is characterized in that, comprise MEMS sensitive element, capacitance-to-digital conversion module, DA conversion module, serial port module and main control module; MEMS sensitive element is connected with capacitance-to-digital conversion module, main The control module is respectively connected with the DA conversion module, the capacitance-to-digital conversion module and the serial port module;

The capacitance-to-digital conversion module is connected with the MEMS sensitive element, and directly converts the capacitance signal into a digital signal and transmits it to the main control module. The main control module converts the capacitance value into the air pressure value according to the relationship between the capacitance of the sensitive element and the air pressure. After framing, it is output through the serial port module, the DA conversion module communicates with the main control module, and the calibrated air pressure value is linearly converted into a voltage output through the MCU.

2. the device of a kind of MEMS integrated air pressure sensor dual output according to claim 1, it is characterized in that, described capacitance-to-digital conversion module selects PCAP02 chip for use, and chip is connected with MEMS sensitive element, and passes between main control module IIC protocol communication.

3 . The device for dual output of a MEMS integrated air pressure sensor according to claim 1 , wherein the main control module selects STM32. 4 .

4. the device of a kind of MEMS integrated air pressure sensor dual output according to claim 1, is characterized in that, described serial port module selects MAX232 level conversion chip for use, and the TTL signal output by main control module is converted into standard RS232 signal output.

5. the device of a kind of MEMS integrated air pressure sensor dual output according to claim 1, it is characterized in that, described DA conversion module selects dual 12-bit high-speed serial DA chip TLV5618, has two DA outputs, absolutely The pressure type and the middle fixed type share one DA output, and the other DA output is used for the differential pressure type.