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CN-121994402-A - Hardware temperature and pressure compensation sensing module based on LTCC embedded structure and preparation method

CN121994402ACN 121994402 ACN121994402 ACN 121994402ACN-121994402-A

Abstract

The invention discloses a hardware temperature and pressure compensation sensing module based on an LTCC embedded structure and a preparation method thereof, and relates to the technical field of sensors; the module comprises an LTCC substrate body, an embedded main control unit, a surface sensing unit and an embedded hardware temperature compensation network, wherein a closed embedded cavity is formed inside the LTCC substrate and is provided with a vertical interconnection conductor, the main control unit is embedded in the cavity, the surface sensing unit outputs differential signals containing temperature drift, an embedded thermistor and a voltage division filter form temperature reference signals, the compensation resistor is used for zero point calibration, a later signal conditioning circuit amplifies the differential signals, and the pressure signals and the temperature reference signals are overlapped and low-pass filtered according to a weighted proportion in an analog domain, so that temperature drift is counteracted and then output to a main control analog-digital conversion end.

Inventors

  • HUANG ZHAOLING
  • WANG RUYAN
  • WU ZHOUHUA
  • HUANG JIAWEI
  • Bai Jiaozhuang

Assignees

  • 桂林电子科技大学

Dates

Publication Date
20260508
Application Date
20260211

Claims (10)

  1. 1. Hardware temperature and pressure compensation pressure sensing module based on LTCC embedded structure, its characterized in that includes: The device comprises an LTCC substrate body (1), an embedded main control unit (3), a surface sensing unit (2) and an embedded hardware temperature compensation network; a sealed embedded cavity (10) is formed in a preset area inside the LTCC substrate body (1), and vertical interconnection conductors are arranged between ceramic layers inside the LTCC substrate body (1); the embedded main control unit (3) is arranged in the embedded cavity (10); The surface sensing unit (2) is attached to the surface of the LTCC substrate body (1), and the surface sensing unit (2) outputs an original differential signal containing a temperature drift component; The embedded hardware temperature compensation network comprises an embedded thermistor (41) and an embedded compensation resistor (42) which are printed on an inner ceramic layer of the LTCC substrate body (1), wherein the embedded thermistor (41) is connected with the partial pressure filter element to form a temperature sampling node and output a temperature reference signal, and the embedded compensation resistor (42) is connected with the zero calibration branch; The LTCC substrate body (1) integrates a pre-differential amplifying circuit (200) and an active filtering and secondary amplifying circuit (400), the pre-differential amplifying circuit (200) amplifies an original differential signal to obtain a pressure analog signal, the active filtering and secondary amplifying circuit (400) is configured as a hardware temperature compensation calculating unit, the input end of the hardware temperature compensation calculating unit comprises a weighted superposition node, the weighted superposition node receives the pressure analog signal through a first weighted resistor and receives a temperature reference signal through a second weighted resistor, the weighted superposition node receives a virtual reference voltage through a bias branch, the active filtering and secondary amplifying circuit (400) amplifies the weighted superposition node signal in an analog domain and performs active low-pass filtering, temperature drift cancellation is achieved through a ratio of resistance values of the first weighted resistor and the second weighted resistor, and the pressure sampling signal after temperature compensation is output to an analog-digital conversion input end of the embedded main control unit (3).
  2. 2. The hardware temperature and pressure compensation sensing module based on the LTCC embedded structure of claim 1 is characterized in that the vertical interconnection conductor comprises a signal transmission blind hole (61), an internal interconnection via hole (62), a heat dissipation via hole (63) and a grounding via hole (64), one end of the signal transmission blind hole (61) is connected with the surface sensing unit (2), the other end of the signal transmission blind hole (61) penetrates through the ceramic layer and is connected with the embedded main control unit (3) through the internal interconnection via hole (62), the heat dissipation via hole (63) is arranged below the embedded main control unit (3) and is communicated with the bottom of the LTCC substrate body (1), and the grounding via hole (64) penetrates through two sides of the LTCC substrate body (1) and is connected with the grounding shielding layer (8) inside the substrate to form the electromagnetic shielding structure.
  3. 3. The LTCC embedded structure-based hardware temperature and pressure sensing module as claimed in claim 1, wherein the embedded compensation resistor (42) is a laser trimming resistor, and the embedded compensation resistor (42) is used for eliminating the initial zero deviation of the wheatstone bridge through resistance trimming after preparation.
  4. 4. A hardware temperature-compensated pressure sensing module based on an LTCC embedded structure as claimed in any one of claims 1 to 3, wherein the LTCC substrate body (1) integrates a signal conditioning link, the signal conditioning link sequentially comprises a pre-differential amplifying circuit (200), an active filtering and secondary amplifying circuit (400) and an analog-to-digital conversion interface circuit (300), an input end of the pre-differential amplifying circuit (200) is connected with an output end of the sensing and temperature-compensated front-end circuit (100), the pre-differential amplifying circuit (200) comprises an instrumentation amplifier (U1), a reference end of the instrumentation amplifier (U1) is connected with a virtual reference voltage, the virtual reference voltage is generated by a voltage dividing network and is output through a buffer circuit, and the virtual reference voltage is used as a reference potential of the signal conditioning link and the analog-to-digital conversion interface circuit (300).
  5. 5. The hardware temperature-compensation pressure sensing module based on the LTCC embedded structure of claim 4, wherein the front differential amplification circuit (200) is provided with a gain calibration network, the gain calibration network comprises a fixed resistor and an adjustable resistor, the active filtering and secondary amplification circuit (400) comprises an operational amplifier (U2) and a resistor-capacitor network, the resistor-capacitor network and the operational amplifier (U2) form a second-order active low-pass filter, the analog-to-digital conversion interface circuit (300) comprises a pressure sampling output end and a temperature sampling output end, and the pressure sampling output end and the temperature sampling output end are respectively provided with an input filtering network formed by a series resistor and a parallel capacitor and are used for being connected into an analog-to-digital conversion input end of the embedded main control unit (3) after anti-aliasing filtering.
  6. 6. A method for manufacturing a hardware temperature and pressure compensation sensing module based on an LTCC embedded structure as claimed in any one of claims 1 to 5, comprising the steps of: Step S1, providing an LTCC green ceramic tape, forming interlayer through holes at preset positions, and forming a cavity contour structure for reserving a cavity in a region corresponding to the embedded cavity (10); s2, filling conductive paste into the interlayer through holes to form metal through holes, wherein the metal through holes comprise signal transmission blind holes (61), internal interconnection through holes (62), heat dissipation through holes (63) and grounding through holes (64); Step S3, printing conductive paste on the surface of the green ceramic tape to form an interlayer metal wire (7), printing resistor paste on the surface of the green ceramic tape, printing an internal ceramic layer to form an embedded thermistor (41) and an embedded compensation resistor (42), and electrically connecting the embedded thermistor (41) and the embedded compensation resistor (42) with the interlayer metal wire (7) and the metal via hole respectively; S4, aligning and laminating all layers of green ceramic tapes, and pressing under an isostatic pressing environment to form ceramic green blanks, wherein a space corresponding to the embedded cavity (10) is reserved in the lamination process; S5, performing low-temperature co-sintering on the ceramic green body to form an integrated LTCC substrate body (1), and forming an embedded cavity (10) and a vertical interconnection conductor; And S6, mounting a surface sensing unit (2) and a surface mounting passive device (5) on the surface of the LTCC substrate body (1), and mounting a buried main control unit (3) in the buried cavity (10) to complete electrical connection and encapsulation solidification.
  7. 7. The method for manufacturing a hardware temperature-compensated pressure sensor module based on an LTCC embedded structure as claimed in claim 6, wherein after the printing is completed in step S3, a laser trimming process is performed on the embedded compensation resistor (42), and the initial zero-point deviation of the wheatstone bridge is eliminated through the resistance trimming.
  8. 8. The method for manufacturing the hardware temperature-compensated pressure sensing module based on the LTCC embedded structure of claim 7, wherein the laser trimming process uses virtual reference voltage as a target reference to calibrate zero output of an output end of the Wheatstone bridge, so that the zero output falls into a preset tolerance range.
  9. 9. The method for manufacturing a hardware temperature-compensated pressure sensor module based on an LTCC embedded structure as claimed in claim 6, wherein in step S5, the peak temperature of the low-temperature co-sintering is controlled to be 850 ℃ to 900 ℃ and the holding time is 30 to 60 minutes.
  10. 10. The method for manufacturing the hardware temperature and pressure compensation sensing module based on the LTCC embedded structure of claim 6, wherein the step S6 is followed by performing an electrical calibration step, the electrical calibration step comprises adjusting a gain calibration network of the pre-differential amplifying circuit (200) under a constant pressure input condition so that the output amplitude of the pressure sampling output end meets the analog-to-digital conversion dynamic range requirement of the embedded main control unit (3).

Description

Hardware temperature and pressure compensation sensing module based on LTCC embedded structure and preparation method Technical Field The invention relates to the technical field of sensors, in particular to a hardware temperature and pressure compensation pressure sensing module based on an LTCC embedded structure and a preparation method thereof. Background The pressure sensing module is widely applied to industrial control, automobile electronics, environmental monitoring and other scenes, and is generally required to realize pressure signal acquisition, analog conditioning, analog-to-digital conversion and data processing in a limited volume, and keep stable output in a wider temperature range. Along with the increasing demands of applications on miniaturization, low power consumption and high reliability, sensor modules are gradually changed from discrete device stacking to multi-layer substrate and system-in-package integration, and the anti-interference capability and consistency of weak differential signals are improved by shortening interconnection paths and reducing parasitic parameters. Meanwhile, the continuous operation of the main control chip in the module can bring local heat sources, and the temperature change of the external environment can be conducted to the sensitive element along the packaging structure, so that the zero point and the sensitivity of the pressure sensor drift along with the temperature, therefore, how to cooperatively inhibit the temperature drift at the structural, thermal management and circuit layers and take account of mass production consistency and calibration efficiency becomes a key technical direction of the pressure sensing module design. In the prior art, a pressure sensing module adopts a conventional circuit board or a planar interconnection structure to distribute a pressure sensor, an amplifying filter circuit and a main control unit, temperature compensation often depends on a software algorithm or corrects at the rear end of an analog link, so that response delay exists in temperature drift cancellation and processing calculation force is occupied, meanwhile, parasitic parameters and electromagnetic coupling introduced by longer routing and multistage connection are easy to weaken the integrity of differential signals, the packaging volume and wiring space are limited, the heat dissipation path is insufficient, the thermal field is unevenly distributed, synchronous tracking compensation on internal heat sources and environmental heat transfer is difficult to realize, and a reproducible zero point trimming and gain calibration mechanism is lacked, so that the utilization ratio of the effective dynamic range of an analog to digital converter (ADC) is limited, and the comprehensive requirements of high stability, strong anti-interference and high consistency are difficult to be met under the miniaturized condition. In view of this, the present invention proposes a hardware temperature-compensated pressure sensor module based on an LTCC embedded structure and a method for manufacturing the same, so as to solve the above-mentioned problems. Disclosure of Invention Aiming at the defects of the prior art in the background technology, the invention aims to provide a hardware temperature and pressure compensation sensing module based on an LTCC embedded structure and a preparation method. The module utilizes a closed embedded cavity formed by LTCC multilayer cofiring and a vertical interconnection conductor to realize the three-dimensional interconnection of a surface sensing unit and a short path of an embedded main control unit, and integrates an embedded thermistor and a repairable compensation resistor in a substrate to form a hardware temperature compensation network, so that temperature drift offset is completed in real time at the front end of an analog domain, and simultaneously, the heat management and anti-interference capacity is improved through a vertical heat dissipation via hole and a grounding shielding structure, and the reproducible calibration of zero and measuring range is realized by matching with laser trimming and gain calibration, so that the output of the pressure sensing module with low temperature drift, high stability and high consistency is obtained under the miniaturized condition. In order to achieve the above object, the present invention provides the following technical solutions: The hardware temperature-compensation pressure sensing module based on the LTCC embedded structure comprises an LTCC substrate body, an embedded main control unit, a surface sensing unit and an embedded hardware temperature-compensation network, wherein the LTCC substrate body is of a multilayer ceramic medium structure, a closed embedded cavity is formed in a preset area inside the LTCC substrate body, vertical interconnection conductors are arranged among ceramic layers, the embedded main control unit is arranged in the embedded cavity, the surface se