Airflow sensor chip for welding anomaly detection and detection method thereof

Abstract

The invention relates to the technical field of airflow sensors, in particular to an airflow sensor chip for welding anomaly detection and a detection method thereof, and the airflow sensor chip comprises a basic global circuit which provides reference voltage, bias current and clock signals for each module of the chip; the input end of the capacitance frequency conversion circuit is connected with the SE end, the output end is connected with the core logic circuit and the selector, and the capacitance change is converted into a frequency signal; the core logic circuit is used for comparing the frequency with a threshold value and outputting a control signal to drive control; the cold solder joint judgment circuit is embedded into the core logic circuit, periodically records and compares the initial frequency with the real-time frequency, and accumulates the number of abnormal times to trigger an LED to give an alarm; and the mode judgment logic circuit responds to the specific waveform input by the LED end and controls the selector to directly connect the frequency signal to the LED end. The method has the beneficial effects that the welding abnormity can be more easily detected under the conditions that the cost is not increased and the pin distribution of the existing chip and the layout of the microphone circuit board are not changed.

Description

Technical Field

[0001] The present invention relates to the technical field of airflow sensors, and particularly to an airflow sensor chip for detecting welding abnormalities and a detection method thereof. Background Art

[0002] Airflow sensor chips are usually used by being embedded in microphone heads. After assembly, the signal input pins of the chips are wrapped inside the microphone heads, and it is difficult to easily determine welding abnormalities through simple tests, which may cause the microphone heads to malfunction accidentally, and the occurrence time is uncertain, bringing great difficulties to troubleshooting abnormalities.

[0003] In the prior art, functional problems caused by welding abnormalities cannot be determined and detected through simple tests. The occurrence time of accidental activation of the microphone head caused by welding abnormalities is uncertain, and the test time of the finished microphone head is limited, which brings considerable difficulties to troubleshooting abnormalities. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present application proposes an airflow sensor chip for detecting welding abnormalities and a detection method thereof, which can more easily detect welding abnormalities without increasing costs, changing the existing chip pin distribution, and the microphone head circuit board layout.

[0005] The following is the technical solution of the present invention. An airflow sensor chip for detecting welding abnormalities includes: ‌Basic global circuit‌, which provides a reference voltage, a bias current, and a clock signal for each module of the chip; ‌Capacitance-frequency conversion circuit‌, with its input terminal connected to the SE terminal and its output terminal connected to the core logic circuit and the selector, which converts capacitance changes into frequency signals; ‌Core logic circuit‌, which is used to compare the frequency with a threshold value and output a control signal to the drive control; ‌Dry joint determination circuit‌, which is embedded in the core logic circuit, periodically records and compares the initial frequency with the real-time frequency, and accumulates the number of abnormal times to trigger an LED alarm; ‌Mode determination logic circuit‌, which responds to a specific waveform input at the LED terminal and controls the selector to directly pass the frequency signal to the LED terminal.

[0006] As a preferred solution of the present invention, it further includes: a ‌LORA module‌, which is used to transmit the frequency value and the number of abnormal times to a remote terminal.

[0007] As a preferred solution of the present invention, the dry joint determination circuit records the number of frequency abnormalities through an accumulator. When the accumulated number exceeds the set threshold, it triggers a flashing alarm at the LED terminal and distinguishes between types of pin breakage or poor contact.

[0008] As a preferred solution of the present invention, the LED driving module works in coordination with the mode determination logic circuit, and when there is leakage at the SE end, the frequency deviation anomaly is screened according to a preset empirical threshold.

[0009] As a preferred solution of the present invention, the protection circuit integrates over-current, over-temperature and short-circuit detection functions, and monitors abnormal conditions in real time through the power sampling feedback module and the output sampling feedback module.

[0010] As a preferred solution of the present invention, the square wave signal output by the capacitor frequency conversion circuit is output to the LED end after frequency division processing.

[0011] As a preferred solution of the present invention, the charging management module starts battery charging when the voltage at the VCC terminal is higher than a set threshold, and controls the charging state in conjunction with the core logic circuit.

[0012] A method for detecting an airflow sensor chip for welding abnormality detection comprises the following steps: S1. Complete the microphone assembly and solder the chip to the circuit board, or embed the circuit board into the microphone structure; S2, power on self-test, verify the connection status of VDD, OUT and LED, and switch to input mode after the LED flashes; S3, input a continuous square wave signal with a period of 10μS through the LED end to test the abnormal connection of the SE end; S4, the cold soldering judgment circuit periodically compares the initial frequency with the real-time frequency, and the accumulated number of times exceeding the threshold triggers the LED alarm.

[0013] As a preferred solution of the present invention, in S2, multimodal detection is performed: During the power-on self-test phase, input 1kHz high and low level waveforms to the LED end to verify the integrity of the output waveform; ‌During the static monitoring phase, the LED flashes quickly n Flash or slow flash n -1 time to distinguish the type of cold solder joint.

[0014] As a preferred solution of the present invention, in S3, a mutual information feature construction algorithm is used to extract the time series correlation characteristics of the sensor signal, and a dynamic frequency threshold model is constructed. When the frequency deviation exceeds ±10% and lasts for several update cycles, it is determined to be abnormal.

[0015] The beneficial effects of the present invention are: In the present invention, the chip is placed in the microphone head, and the frequency square wave signal converted by the chip input terminal capacitor is directly output from the LED port through the chip pin multiplexing technology; In the present invention, a circuit for determining a dry joint of an internal input pin of a chip records an initial value of the frequency converted by the input pin after power-on, and periodically compares the existing frequency value with the initial value; when the change in the frequency value exceeds a set threshold and lasts for the initial value update duration, the number of abnormal occurrences is recorded, and an alarm is triggered when the cumulative number of abnormal occurrences exceeds the set threshold. In the present invention, it is possible to more easily detect soldering abnormalities without changing the existing chip pin distribution and the layout of the microphone circuit board, thereby well eliminating microphone factory abnormalities without increasing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of the chip and the peripheral application circuit structure of the present invention; Figure 2 is a schematic diagram of the chip of the present invention; Figure 3 is a state diagram of the dry joint detection function in the chip of the present invention; Figure 4 is a flowchart of the chip detection method of the present invention; Figure 5 is a state diagram of the chip detection method of the present invention; In the figure: 100, chip; 101, airflow sensor; 102, light-emitting diode; 103, capacitor; 104, VDD terminal; 105, VCC terminal; 106, GND terminal; 201, basic global circuit; 202, capacitor frequency conversion circuit; 203, charging management module; 204, core logic circuit; 205, dry joint determination circuit; 206, protection circuit; 207, power sampling feedback module; 208, drive control; 209, output sampling feedback module; 210, LED drive module; 211, selector; 212, mode determination logic circuit; 213, switching transistor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] To make the technical problems solved, the technical solutions adopted, and the technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present invention. Embodiment

[0018] As Figures 1 to 3 shown, an airflow sensor 101 chip for detecting soldering abnormalities includes: a VCC terminal 105, a VDD terminal 104, an SE terminal, an OUT terminal, an LED terminal, and a GND terminal 106.

[0019] The VCC terminal 105 is connected to a charging interface; The VDD terminal 104 is connected to a power supply; The OUT terminal is used to connect a load resistor; A capacitor 103 is connected between the VDD terminal 104 and the GND terminal 106 to reduce the fluctuation of the battery voltage during operation; A light-emitting diode is connected between the LED terminal and the GND terminal 106 to display the working state of the chip 100; An airflow sensor 101 is connected between the SE terminal and the GND terminal 106, which converts the airflow change into a capacitance value change of the capacitor 103 and inputs it into the chip 100.

[0020] In this embodiment, on the chip 100 of the airflow sensor 101, there are a VCC terminal 105, a VDD terminal 104, an SE terminal, an OUT terminal, an LED terminal, and a GND terminal 106. The VCC terminal 105 is used to connect a charging interface. An airflow sensor 101 is connected across the SE terminal and the GND terminal 106, and the LED terminal is connected to the positive terminal of the light-emitting diode. The GND terminal 106 is connected to the negative terminal of the LED terminal.

[0021] In this embodiment, the chip 100 is placed in a microphone. The metal diaphragm in the microphone is equivalent to the capacitor 103 sensor. The change in capacitance 103 caused by air pressure also causes a corresponding change in the frequency of the oscillator at the SE terminal. If the connection of the SE terminal is abnormal, then the frequency of the SE terminal will also deviate from the normal range, and even the deviation amplitude is very large. The SE port is wrapped and the frequency at this place cannot be measured by an instrument. Even if the SE port is exposed outside the microphone, when the probe of the test instrument touches the solder joint of the SE terminal, it will cause a change in frequency due to the introduction of an additional capacitor 103. The signal at this place is amplified into a square wave signal by the internal circuit of the chip 100, either directly passed or processed through frequency division, and then output to the LED terminal. Testing the square wave signal at the LED terminal can measure the frequency of the SE port.

[0022] The core modules of the airflow sensor 101 chip 100 include: a basic global circuit 201, a core logic circuit 204, a charging management module 203, a capacitance-frequency conversion circuit 202, a drive control 208, an MOS switch, a power sampling feedback module 207, an output sampling feedback module 209, a protection circuit 206, an LED drive module 210, a selector 211, a mode determination logic circuit 212, and a dry joint determination circuit 205.

[0023] The basic global circuit 201 is connected to each module in the chip 100, and provides a reference voltage, a bias current, an enable signal, and a clock signal for each module of the chip 100.

[0024] The capacitance frequency conversion circuit 202 is used to convert the electrical characteristics of the airflow sensor 101 into a frequency. Its input terminal is connected to the SEN terminal of the chip 100, and its output terminal is connected to the core logic circuit 204 and the selector 211.

[0025] The core logic circuit 204 is connected to the capacitance frequency conversion circuit 202, the charging management module 203, the protection circuit 206, the drive control 208, and the selector 211. The main functions of the core logic circuit 204 include: Comparing the frequency change with the threshold frequency to determine whether to turn on the switching transistor 213; Comprehensively judging the signals input by each unit circuit and outputting a control signal to the drive control 208.

[0026] The drive control 208 is connected to the input terminal of the MOS switch and the output terminal of the core logic circuit 204. The source and drain of the MOS switch are respectively connected to the VDD terminal 104 and the OUT terminal. The processing result of the core logic circuit 204 is output to the drive control 208, and the output terminal of the drive control 208 is connected to the gate of the switching transistor 213, that is, the input terminal of the switching transistor 213, so as to realize the control of the switching transistor 213.

[0027] The charging management module 203 is used to detect and judge that when the voltage of the VCC terminal 105 is higher than the set threshold, it realizes the charging of the battery, and is connected to the VCC terminal 105 and the core logic circuit 204.

[0028] The protection circuit 206 is used to output the detected overcurrent signal, overtemperature signal, and short - circuit state to the core logic circuit 204. Its input terminal is connected to the power sampling feedback module 207 and the output sampling feedback module 209, and its output terminal is connected to the core logic circuit 204.

[0029] The LED drive module 210 is used to control the on - off and brightness state of the LED terminal, and is connected to the LED terminal, the selector 211, and the mode determination logic circuit 212.

[0030] The mode determination logic circuit 212 is used to control the selector 211 to directly connect the waveform of the capacitance frequency conversion circuit 202 to the LED driving module 210 and drive the LED terminal when a specific waveform is input at the LED terminal, and is connected to the selector 211, the LED terminal and the LED driving module 210. If the connection of the SE terminal of the chip 100 is abnormal, such as open circuit or short circuit, the output frequency will deviate far from the normal value, and the problem source can be clearly located at the SE port; if there is leakage at the SE terminal of the chip 100 due to excessive use of solder paste, the frequency output from the LED terminal will also deviate from the normal value to a certain extent, and a threshold can be set by experience to screen such abnormalities; if the chip 100 and the microphone do not show abnormalities in a short time after assembly, but experience abnormal SE terminals after transfer transportation or use. Such abnormalities are identified by the dry joint determination circuit 205 for their abnormal behavior, and the LED terminal is triggered to flash and alarm.

[0031] The dry joint determination circuit 205 is embedded in the core logic circuit 204 and is connected to the selector 211. After power-on, the initial value of the frequency is recorded, and the real-time frequency is compared with the initial value periodically. When the frequency change is greater than the set threshold and exceeds the initial value update duration, it is recorded that the disconnection action caused by dry joint has occurred once. The accumulator records the number of times this event occurs. When it is greater than the set number of times, it is considered that the microphone has abnormal disconnection and connection caused by dry joint, and the LED terminal is triggered to alarm. Embodiment

[0032] Such as Figure 4 And Figure 5 As shown in the figure, a detection method for a gas flow sensor 101 chip for detecting welding abnormalities includes the following steps: S1. Microphone assembly and chip 100 welding; S2. Port self-check and function verification; S3. Detect the connection status of the SE terminal; S4. Dry joint dynamic determination and alarm.

[0033] In step S1, the microphone is assembled and the chip 100 is welded. Specifically, the microphone is assembled and the chip 100 is welded to the circuit board, or the circuit board is embedded in the microphone structure. In step S2, port self-check and function verification are performed. Specifically, after power-on, the chip 100 automatically performs voltage detection. If it is normal, the LED terminal is triggered to flash once; the connection status of the VDD terminal 104, the OUT terminal and the LED terminal can be verified through the load plug and unplug test. After the LED terminal finishes flashing, its driving MOS transistor is turned off, and at this time, the LED port can be switched to the input mode. In step S3, the connection status of the SE terminal is detected. Specifically, a specific square wave signal is input through the LED terminal, for example, 10 consecutive waveforms with a period of 10 μS, to trigger the frequency direct-through mode, that is, the internal mode determination logic circuit 212 of the chip 100, so that the output of the capacitance frequency conversion circuit 202 is directly connected to the LED terminal. The frequency output from the LED terminal is tested. If the SE terminal is open or short-circuited, the frequency significantly deviates from the normal range, and it is determined that the problem originates from the SE terminal; if there is leakage, such as flux residue, the frequency shifts slightly, and it is determined whether it is abnormal through a preset threshold. If the SE terminal of the chip 100 is abnormally connected, such as open or open circuit, the output frequency will deviate far from the normal value, and the problem can be clearly located as originating from the SE port; if the SE terminal of the chip 100 has leakage due to excessive use of flux, the frequency output from the LED terminal will also deviate from the normal value to a certain extent, and a threshold can be set through experience to screen such abnormalities.

[0034] In step S4, dynamic determination and alarm of solder joint voids. Specifically, after the microphone is powered on and static, the solder joint void determination circuit 205 periodically compares the real-time frequency with the initial recorded value, and triggers the LED terminal to flash and alarm when the cumulative number of times exceeds the threshold. The solder joint void determination circuit 205 is embedded in the core logic module, and realizes dynamic monitoring by accumulating the number of abnormal events, effectively identifying intermittent solder joint void problems that occur after transportation or use. The initial value of the frequency is recorded immediately after power-on, and the real-time frequency is periodically compared with the initial value. When the frequency change is greater than the set threshold and exceeds the initial value update duration, it is recorded that the disconnection action caused by solder joint voids has occurred once. The number of times of this event is recorded by an accumulator. When it is greater than the set number of times, it is considered that the microphone has abnormal disconnection and connection caused by solder joint voids, and the LED terminal is triggered to alarm.

[0035] In a possible embodiment, dynamic frequency threshold determination is performed. The mutual information feature construction algorithm is used to extract the temporal correlation features of the sensor output signal, construct a dynamic frequency threshold model, and improve the solder joint void detection accuracy; the real-time frequency is periodically compared with the initial frequency value. When the deviation exceeds the threshold of ±10% and lasts for 3 update cycles, an abnormal record is triggered.

[0036] In a possible embodiment, a multi-modal detection mechanism is executed. In the power-on self-check stage, high and low level waveforms (frequency 1 kHz) are input through the LED terminal to test the integrity of the output waveform and determine the welding state of the SE terminal; in the static monitoring stage, after the microphone is powered on and static for 30 seconds, the solder joint void type, pin breakage or poor contact, is distinguished through the LED terminal flashing mode, such as flashing quickly 3 times or slowly 2 times.

[0037] In a possible embodiment, a LORA module is integrated to transmit the detection data to a remote terminal, supporting real-time monitoring of the welding state. The detection data includes frequency values and the number of abnormalities. In the present invention, the chip 100 is placed in the microphone. Through the pin multiplexing technology of the chip 100, the frequency square wave signal converted by the input capacitor 103 of the chip 100 is directly output from the LED port. The chip 100 is internally provided with an input pin dry soldering determination circuit 205, which records the initial value of the frequency converted by the input pin after power-on and periodically compares the existing frequency value with the initial value; when the change in the frequency value exceeds the set threshold and lasts for the initial value update duration, the number of abnormal occurrences is recorded, and an alarm is triggered when the cumulative number of abnormal occurrences exceeds the set threshold.

[0038] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concepts. Obviously, those skilled in the art can make various changes and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the equivalent technology of the present invention, the present invention is also intended to include these modifications and variations.

Claims

1. An airflow sensor chip for detecting welding anomalies, characterized in that, include: ‌Basic global circuit‌, providing reference voltage, bias current and clock signal for each module of the chip; Capacitance frequency conversion circuit, the input end is connected to the SE end, and the output end is connected to the core logic circuit and the selector, which converts the capacitance change into a frequency signal; ‌Core logic circuit‌, used to compare frequency with threshold and output control signal to drive control; ‌Flawed soldering determination circuit‌, embedded in the core logic circuit, periodically records and compares the initial frequency with the real-time frequency, and the accumulated number of abnormalities triggers the LED alarm; The mode determination logic circuit responds to the specific waveform input to the LED end and controls the selector to pass the frequency signal directly to the LED end.

2. The airflow sensor chip for detecting welding anomalies according to claim 1, characterized in that, Also includes: ‌LORA module‌ is used to transmit the frequency value and the number of abnormalities to the remote terminal.

3. The airflow sensor chip for detecting welding abnormalities according to claim 1, characterized in that, The cold soldering judgment circuit records the number of frequency abnormalities through an accumulator. When the accumulated number exceeds the set threshold, the LED end is triggered to flash an alarm and distinguish the type of pin breakage or poor contact.

4. The airflow sensor chip for detecting welding abnormalities according to claim 1, characterized in that, The LED driver module works in conjunction with the mode determination logic circuit to screen out frequency deviation anomalies based on a preset empirical threshold when leakage occurs at the SE end.

5. The airflow sensor chip for detecting welding abnormalities according to claim 1, characterized in that The protection circuit integrates over-current, over-temperature and short-circuit detection functions, and monitors abnormal conditions in real time through the power sampling feedback module and the output sampling feedback module.

6. The airflow sensor chip for detecting welding abnormalities according to claim 1, characterized in that, The square wave signal output by the capacitor frequency conversion circuit is output to the LED end after frequency division processing.

7. The airflow sensor chip for detecting welding abnormalities according to claim 1, characterized in that, The charging management module starts battery charging when the VCC terminal voltage is higher than the set threshold, and works in conjunction with the core logic circuit to control the charging status.

8. A detection method for an airflow sensor chip for detecting welding abnormalities, applicable to the airflow sensor chip for detecting welding abnormalities described in any one of claims 1-7, characterized in that, The following steps are involved: S1. Complete the microphone assembly and solder the chip to the circuit board, or embed the circuit board into the microphone structure; S2, power on self-test, verify the connection status of VDD, OUT and LED, and switch to input mode after the LED flashes; S3, input a continuous square wave signal with a period of 10μS through the LED end to test the abnormal connection of the SE end; S4, the cold soldering judgment circuit periodically compares the initial frequency with the real-time frequency, and the accumulated number of times exceeding the threshold triggers the LED alarm.

9. The detection method of an airflow sensor chip for detecting welding abnormalities according to claim 8, characterized in that, In S2, multimodal detection is performed: During the power-on self-test phase, input 1kHz high and low level waveforms to the LED end to verify the integrity of the output waveform; During the static monitoring phase, distinguish the types of solder joints by the LED flashing n quickly for n n times or slowly for n - 1 times.

10. The detection method of an airflow sensor chip for detecting welding abnormalities according to claim 8, characterized in that, In S3, the mutual information feature construction algorithm is used to extract the time series correlation characteristics of the sensor signal, and a dynamic frequency threshold model is constructed. When the frequency deviation exceeds ±10% and lasts for several update cycles, it is judged to be abnormal.

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