CN-122016094-A - Temperature compensation type crosstalk-proof capacitive sensing array acquisition circuit and control method

CN122016094ACN 122016094 ACN122016094 ACN 122016094ACN-122016094-A

Abstract

The invention belongs to the field of flexible microelectronic circuits, and provides a temperature compensation type crosstalk-proof capacitive sensing array acquisition circuit and a control method thereof, wherein the temperature compensation type crosstalk-proof capacitive sensing array acquisition circuit comprises an excitation signal driving source and a signal detection module; the excitation signal driving source comprises a main control unit, wherein the main control unit generates a row strobe signal and a column strobe signal, the capacitive sensing array performs temperature compensation based on the row strobe signal to obtain a temperature compensation voltage signal, the signal detection module obtains a modulated capacitance voltage signal from capacitance sensing units of columns in the capacitive sensing array, the temperature signal modulation module converts the temperature compensation voltage signal of corresponding columns into a modulated temperature voltage signal according to the column strobe signal of the main control unit, the modulated capacitance voltage signal and the modulated temperature voltage signal are combined into a multiplexing signal through an analog adder, the multiplexing signal is transmitted to an upper computer through the main control unit to be demodulated to obtain a compensated pressure signal, and accurate temperature compensation and signal crosstalk suppression can be realized.

Inventors

XU ZHENJIN
XU TONGMING
Sheng tianyu
ZHANG XU
WEI CHENGLONG
LIN YONGWEN
LI BOZHAO
JING KUN

Assignees

浪潮通用软件有限公司

Dates

Publication Date: 20260512
Application Date: 20260104

Claims (10)

1. The temperature compensation type crosstalk-proof capacitive sensing array acquisition circuit is characterized by comprising an excitation signal driving source and a signal detection module, wherein the excitation signal driving source is respectively connected with a column gating module and a temperature signal modulation module; the excitation signal driving source comprises a main control unit, and the main control unit generates a row strobe signal and a column strobe signal to realize the activation of specific rows and specific columns in the capacitive sensor array; the capacitive sensing array converts temperature signals of capacitive sensing units of corresponding rows into temperature compensation voltage signals based on row strobe signals; The signal detection module is respectively connected with the capacitive sensing array and the column gating module, and converts capacitance signals of the capacitive sensing units of the corresponding columns into modulated capacitance voltage signals based on column gating signals transmitted by the column gating module; the temperature signal modulation module converts the temperature compensation voltage signal of the corresponding column into a modulation temperature voltage signal according to the column gating signal of the main control unit; And combining the modulated capacitor voltage signal and the modulated temperature voltage signal into a multiplexing signal through an analog adder, and transmitting the multiplexing signal to an upper computer through a main control unit for demodulation to obtain a compensated pressure signal.
2. The temperature-compensated crosstalk-prevention capacitive sensing array acquisition circuit of claim 1, wherein the excitation signal driving source further comprises a first direct digital frequency synthesizer and a row strobe bus; The main control unit controls the first direct digital frequency synthesizer to generate an excitation signal to excite the capacitive sensing array through the row strobe bus.
3. The temperature-compensated crosstalk-prevention capacitive sensing array acquisition circuit of claim 1, wherein the row strobe bus determines corresponding row strobe signal lines based on row strobe signals, the rear end of each row strobe signal line is connected in series with a voltage dividing resistor, and one end of the voltage dividing resistor is connected with a corresponding row line in the capacitive sensing array; all the row strobe signal lines are connected with a pull-down resistor, and one end of the pull-down resistor is connected with the system ground potential.
4. The temperature compensation type crosstalk-prevention capacitive sensing array acquisition circuit of claim 1, wherein the capacitive sensing array comprises m multiplied by n capacitive sensing units, and any 2 multiplied by 2 capacitive sensing units and a temperature compensation module are assembled into one capacitive sensing array element; The temperature compensation module performs temperature compensation on the temperature signal of the capacitance sensing unit in the capacitance sensing array element to obtain a temperature compensation voltage signal, and the temperature compensation voltage signal is sent to the temperature signal modulation module through a temperature compensation circuit.
5. The temperature-compensated crosstalk-prevention capacitive sensing array acquisition circuit of claim 4, wherein the temperature compensation module employs a Wheatstone bridge circuit structure comprising a reference arm and a fixed resistance arm in parallel, The reference arm comprises a temperature sensor and a precision adjustable resistor which are connected in series, and the temperature sensor and the precision adjustable resistor are also connected with a direct current power supply module; The fixed resistor arm comprises a first fixed resistor and a second fixed resistor which are connected in series, and the first fixed resistor and the second fixed resistor are grounded; two output ends of the Wheatstone bridge circuit structure are respectively connected with a non-inverting input end and an inverting input end of the first operational amplifier.
6. The temperature-compensated crosstalk-prevention capacitive sensing array acquisition circuit of claim 1, wherein the signal detection module comprises a plurality of signal detection units, each signal detection unit comprising a second operational amplifier, a feedback capacitor, and a feedback resistor; The inverting input end of the second operational amplifier is connected with each column of the capacitive sensing array, the non-inverting input end of the second operational amplifier is grounded, and the output end of the second operational amplifier is connected with the column gating module; The feedback capacitor is connected in parallel with the feedback resistor and then is connected between the inverting input end and the output end of the second operational amplifier.
7. The temperature-compensated crosstalk-prevention capacitive sensing array acquisition circuit of claim 1, wherein the column gating module comprises a column gating bus, the column gating bus being connected with a signal detection module; The column selection bus acquires column selection signals generated by the main control unit and activates corresponding columns in the capacitive sensing array; The column gating bus is also connected with the analog adder, and sends the modulated capacitor voltage signal generated by the signal detection module to the analog adder.
8. The temperature-compensated crosstalk-resistant capacitive sensing array acquisition circuit of claim 1, wherein the temperature signal modulation module comprises a temperature gated bus, a second direct digital frequency synthesizer, and an analog multiplier; The temperature gating bus acquires a column gating signal generated by the main control unit, selects a temperature compensation voltage signal of a corresponding column in the capacitive sensing array, and sends the temperature compensation voltage signal to the analog multiplier; The second direct digital frequency synthesizer generates an auxiliary carrier according to the control signal of the main control unit and sends the auxiliary carrier to the analog multiplier; and multiplying the temperature compensation voltage signal and the auxiliary carrier wave through an analog multiplier to obtain a modulated temperature voltage signal, and sending the modulated temperature voltage signal to an analog adder.
9. A control method based on the temperature compensation type crosstalk-proof capacitive sensing array acquisition circuit according to any one of claims 1 to 8, characterized by comprising: generating a column gating signal and a row gating signal according to a main control unit in the excitation signal driving source, and respectively transmitting the column gating signals to a column gating module and a temperature signal modulation module; The drive source of the excitation signal activates the corresponding row in the capacitive sensing array according to the column gating signal; The temperature compensation module acquires temperature signals of the capacitance sensing units in the activated rows and the activated columns, performs temperature compensation on the temperature signals to obtain temperature compensation voltage signals of the activated rows, and sends the temperature compensation voltage signals of the activated rows to the temperature signal modulation module through a temperature compensation circuit; The signal detection module acquires a capacitance signal of a capacitance sensing unit in an activated column to perform modulation conversion to obtain a modulated capacitance voltage signal, and sends the modulated capacitance voltage signal to a column selection communication line of the activated column in the row gating module; the temperature signal modulation module multiplies the temperature compensation voltage signal of the activated row with the second direct digital frequency generation auxiliary carrier wave to obtain a modulated temperature voltage signal; The analog adder receives the modulated capacitor voltage signal of the column gating module and the modulated temperature voltage signal of the temperature signal modulation module and combines the signals into a multiplexing signal; and transmitting the multiplexing signal to an upper computer through a main control unit for demodulation to obtain a compensated pressure signal.
10. The method for controlling the temperature-compensated anti-crosstalk capacitive sensing array acquisition circuit according to claim 9, wherein the transmitting the multiplexed signal to the host computer through the main control unit for demodulation to obtain the compensated pressure signal comprises: the main control unit converts the multiplexing signal through an ADC and sends the multiplexing signal to a digital quadrature demodulation module in the upper computer; the digital orthogonal demodulation module is used for preprocessing the multiplexing signal to obtain a preprocessed multiplexing signal; multiplying the preprocessed multiplexing signal with a pressure reference signal, and then filtering to obtain a pressure amplitude; multiplying the preprocessed multiplexing signal with a temperature reference signal, and then filtering to obtain a temperature amplitude; And carrying out linear correction on the pressure amplitude to obtain an actual pressure value, mapping the temperature amplitude by a look-up table to determine an actual temperature value, and obtaining a compensated pressure signal according to the temperature compensation coefficient, the actual temperature value and the actual pressure value.

Description

Temperature compensation type crosstalk-proof capacitive sensing array acquisition circuit and control method Technical Field The invention belongs to the technical field of flexible microelectronic circuits, and particularly relates to a temperature compensation type crosstalk-proof capacitive sensing array acquisition circuit and a control method. Background The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. The capacitive pressure sensing array has wide prospect in the fields of high-precision pressure mapping such as robot touch perception, flexible electronic skin, biomedical monitoring and the like by virtue of high sensitivity, low power consumption and excellent dynamic response characteristics. However, with the continuous improvement of the requirements of the application scene on measurement precision, reliability and system integration, the prior art faces a plurality of key technical bottlenecks in actual deployment, and particularly has serious challenges in measurement consistency under a non-uniform temperature field, signal crosstalk suppression in high-density integration, multi-parameter high-integrity synchronous acquisition and the like. Firstly, under complex temperature field conditions, spatial non-uniformity of the temperature field poses a significant threat to the consistency of capacitance measurement, so that the consistency and stability of capacitance measurement are significantly affected. Although the sensitivity of the capacitance sensing unit to temperature is generally lower than that of the piezoresistive unit, key parameters such as dielectric constant, electrode spacing and the like of the dielectric layer material still drift along with the change of the ambient temperature, so that measurement errors of capacitance values are caused. In practical application, the surface of the sensing array often has obvious temperature gradient distribution, for example, caused by local heat source contact or uneven power consumption of the array, so that sensing units in different areas are in different temperature working conditions. The traditional global temperature compensation strategy only depends on the temperature information of a single reference point, and is difficult to effectively sense and respond to the slight temperature space distribution difference in the array, so that accurate differential correction aiming at units in different temperature intervals cannot be realized, and the overall measurement accuracy is reduced. Secondly, under the background that the array integration level is continuously improved, the detection precision and reliability are severely restricted by the signal crosstalk problem. In order to meet the requirement of high-density integration, a line-column scanning architecture is generally adopted in a capacitive sensing array, however, a parasitic capacitance path is formed between an ungated unit and a tested (gated) unit in the architecture through a shared line-column wiring, so that obvious charge shunt and electric field coupling effects are caused, signal crosstalk is generated, and accurate extraction of a target unit signal is seriously interfered. Along with the expansion of the array scale and the reduction of the cell spacing, the parasitic capacitance effect increases in a nonlinear manner, so that signal distortion is further aggravated, and the detection precision and reliability are severely restricted. In the existing anti-crosstalk technology, such as a method of switch isolation and the like, although crosstalk can be restrained to a certain extent, additional parasitic parameters are often introduced, or a sensor is limited by technology and reliability in flexible substrate application, so that effective balance between performance and integration level is difficult to realize. Furthermore, existing systems have architectural limitations in terms of multi-parameter simultaneous acquisition and anti-interference capabilities. In order to realize synchronous monitoring of pressure and temperature parameters, the traditional scheme generally adopts mutually independent analog signal acquisition channels to respectively perform signal conditioning and analog-to-digital conversion. The parallel architecture not only increases the number of components of the system, the area of a circuit board and the overall cost, but also introduces additional channel mismatch errors due to incomplete matching of analog front-end elements among different channels in the aspects of gain, bias, temperature drift characteristics and the like, damages the synchronism and the associated accuracy of multi-parameter data in time and space, and limits the compensation effect based on multi-parameter fusion. In addition, in the aspect of signal excitation and acquisition mechanism, the traditional direct current or single frequency alternating current e