ESD monitor, ESD monitoring system and ESD monitoring method

Abstract

The invention provides an ESD monitor, an ESD monitoring system and an ESD monitoring method.A detection circuit of the ESD monitor is connected with an ESD monitoring interface and a main control chip, the ESD monitoring interface is connected with an external ESD protection link, and the detection circuit is used for converting a square wave excitation signal sent by the main control chip into a sawtooth wave voltage signal and applying the sawtooth wave voltage signal to a monitoring point of the external ESD protection link; the main control chip is used for sending a square wave excitation signal to the detection circuit and collecting response voltage change generated when the sawtooth wave voltage signal is applied to the monitoring point; and obtaining an ESD monitoring result of the ESD protection link according to the response voltage change. The response voltage change can reflect the time domain change characteristics of the monitoring point, the interference of the ground potential difference can be avoided, and the ESD monitoring result of the ESD protection link is obtained based on the interference. Therefore, simulation comparison can be replaced by data analysis, and the reliability of ESD detection is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ESD monitor, in particular to an ESD monitor, an ESD monitoring system and an ESD monitoring method. BACKGROUND

[0002] Electro-static discharge (ESD) is extremely destructive to high-precision electronic components, which can lead to potential damage to products, yield reduction and a sharp increase in after-sales failure rate. Therefore, in the manufacturing fields of electronics, semiconductors, medical devices and aerospace, ESD protection is a core link to ensure product reliability, production safety and supply chain efficiency. In order to monitor the grounding state of the ESD protection link (wrist strap / tablet cushion / equipment shell) in the production station in real time, an ESD monitor is usually deployed for continuous monitoring.

[0003] The traditional ESD monitor compares the collected voltage of the external ESD protection link monitoring point with the reference voltage by using a hardware comparator to determine the state of the external ESD protection link. Due to the influence of the comparison accuracy of the hardware comparator, the detection reliability of the traditional ESD monitor is low. SUMMARY

[0004] To solve the existing technical problems, the present application provides an ESD monitor with improved reliability, an ESD monitoring system and an ESD monitoring method.

[0005] In a first aspect, an ESD monitor is provided, comprising: a master control chip, an ESD monitoring interface and a detection circuit;

[0006] The ESD monitoring interface is used to access the external ESD protection link.

[0007] The detection circuit is connected to the ESD monitoring interface and the master control chip, and is used to convert the square wave excitation signal sent by the master control chip into a sawtooth wave voltage signal and apply it to the monitoring point of the external ESD protection link.

[0008] The master control chip is used to send a square wave excitation signal to the detection circuit, collect the response voltage change generated by the sawtooth wave voltage signal applied to the monitoring point, and obtain the ESD monitoring result of the ESD protection link according to the response voltage change.

[0009] In a second aspect, an ESD monitoring system is provided, comprising a plurality of ESD monitors according to the above embodiments, deployed at each station on the production line, and used to connect the ESD protection link at the station through the ESD monitoring interface of the ESD monitor.

[0010] Each ESD monitor is interconnected based on a preset protocol.

[0011] In a third aspect, an ESD monitoring method is provided, which is applied to an ESD monitor, and the method comprises:

[0012] sending a square wave excitation signal to a detection circuit, which converts the square wave excitation signal into a sawtooth voltage signal and applies the sawtooth voltage signal to a monitoring point of an external ESD protection link;

[0013] collecting a response voltage change generated by the sawtooth voltage signal applied to the monitoring point;

[0014] obtaining an ESD monitoring result of the ESD protection link according to the response voltage change.

[0015] The ESD monitor, the ESD monitoring system and the ESD monitoring method provided by the above embodiments have the following advantages. The detection circuit of the ESD monitor is connected to the ESD monitoring interface and the master control chip. The ESD monitoring interface is connected to the ESD protection link. The detection circuit is used to convert the square wave excitation signal sent by the master control chip into a sawtooth voltage signal and apply the sawtooth voltage signal to the monitoring point of the external ESD protection link. The master control chip is used to collect the response voltage change generated by the sawtooth voltage signal applied to the monitoring point. According to the response voltage change, the ESD monitoring result of the ESD protection link is obtained. The response voltage change can reflect the time domain change characteristics of the monitoring point, can avoid the interference of the ground potential difference, and can obtain the ESD monitoring result of the ESD protection link based on this. Therefore, the intuitive data analysis can replace the analog comparison, and the reliability of the ESD detection is improved. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 FIG. 1 is a structural schematic diagram of an ESD monitor according to an embodiment.

[0017] Figure 2 FIG. 2 is an exploded structural schematic diagram of the ESD monitor according to the embodiment.

[0018] Figure 3 FIG. 3 is a structural schematic diagram of an ESD monitor according to an embodiment.

[0019] Figure 4 FIG. 4 is a circuit structural schematic diagram of the structure of the ESD monitor according to the embodiment.

[0020] Figure 5 FIG. 5 is a circuit structural schematic diagram of the detection circuit according to an embodiment.

[0021] Figure 6 FIG. 6 is a circuit structural schematic diagram of the detection circuit according to an embodiment.

[0022] Figure 7 FIG. 7 is a circuit structural schematic diagram of the structure of the ESD monitor according to the embodiment.

[0023] Figure 8 The schematic diagram of the architecture of the ESD monitoring system in an embodiment.

[0024] Figure 9 The schematic diagram of the flow of the ESD monitoring method in an embodiment.

[0025] In the figure: 10, monitor; 101, shell; 1012, first part; 10121, first end plate; 10122, second end plate; 10123, top plate; 1011, second part; 10111, first side plate; 10112, second side plate; 10113, bottom plate; 1013, mounting part; 102, main control chip; 103, detection circuit; 104, ESD monitoring interface; 1041, first ESD monitoring interface; 1042, second ESD monitoring interface; 105, human body proximity sensor; 1051, induction window; 106, differential signal communication module; 1061, RS485 communication chip; 1062, Type-C interface; 107, single-ended signal communication module; 1071, serial communication chip; 1072, Type-B interface; 108, wireless communication module; 109, drive chip; 110, multiplexing interface; 111, sound alarm; 1110, multi-hole matrix; 112, status indicator light; 113, mechanical switch; 114, power management module; 115, power input interface 115; 116, fixing hole; 20, external ESD protection link; 117, PCB. DETAILED DESCRIPTION

[0026] The technical solutions of the present application will be further described in detail below in combination with the accompanying drawings and specific embodiments.

[0027] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in combination with the accompanying drawings. The described embodiments should not be regarded as limiting the present application. All other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present application.

[0028] In the following description, the expression "some embodiments" describes a subset of all possible embodiments, and it should be noted that "some embodiments" can be the same subset or different subsets, and can be combined with each other without conflict.

[0029] It is to be understood that where an element such as a layer, region or substrate is described as being "on" another element, it can be directly on the other element or intervening elements can also be present. Where an element such as a layer, region or substrate is described as being "connected" to another element, it can be directly connected to the other element or intervening elements can also be present. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0030] An ESD monitor 10, as shown, includes a master control chip 102, an ESD monitoring interface 104 and a detection circuit 103. Figures 1 to 4 The master control chip 102 is connected to the detection circuit 103, and is configured to send a square wave excitation signal to the detection circuit 103, collect a response voltage change generated by the application of the sawtooth wave voltage signal at the monitoring point, and obtain an ESD monitoring result of the ESD protection link according to the response voltage change.

[0031] The ESD monitoring interface 104 is configured to access an external ESD protection link 20.

[0032] The detection circuit 103 is connected to the ESD monitoring interface 104 and the master control chip 102, and is configured to convert the square wave excitation signal sent by the master control chip into a sawtooth wave voltage signal and apply the sawtooth wave voltage signal to a monitoring point of the external ESD protection link.

[0033] The master control chip 102 is connected to the detection circuit 103, and is configured to send a square wave excitation signal to the detection circuit 103, collect a response voltage change generated by the application of the sawtooth wave voltage signal at the monitoring point, and obtain an ESD monitoring result of the ESD protection link according to the response voltage change.

[0034] In a specific embodiment, the ESD monitor 10 includes a PCB board 117 arranged in the housing 101. The PCB board 117 integrates the master control chip 102 and the detection circuit 103, and provides electrical connections for the electronic components of the ESD monitoring interface 104 and the detection circuit 103. The ESD monitoring interface 104 is arranged on the housing 101 and connected to the PCB board through a connector or a wire.

[0035] Specifically, the monitor 10 includes a housing 101, and the master control chip 102 and the detection circuit 103 are arranged in the housing 101. The ESD monitoring interface 104 is arranged on the housing 101, which facilitates the staff to plug in the external ESD protection link 20.

[0036] A plurality of ESD protection links are usually arranged on a production station to meet the needs of anti-static production. Common ESD protection links include a wrist strap discharge link corresponding to an anti-static wrist strap, a table pad grounding link corresponding to a production equipment table pad, and a device grounding link corresponding to a device shell.

[0037] The wrist strap discharge link includes, in sequence, an operator's skin, a wrist strap, a cable and the ground.

[0038] The desk mat grounding link comprises a desk mat surface, a conductive layer, a grounding buckle and the ground in sequence.

[0039] The equipment grounding link comprises an equipment shell, a grounding wire, a grounding point and the ground in sequence.

[0040] The anti-static wristband is connected in series with the ground through a built-in resistor with a small resistance value (such as a 1MΩ resistor). When in use, the metal buckle is tightly attached to the skin, thereby discharging the static electricity of the human body and limiting the current flowing through the human body to prevent the risk of electric shock.

[0041] The anti-static wristband is connected in series with the ground through a built-in resistor with a small resistance value (such as a 1MΩ resistor). When in use, the metal buckle is tightly attached to the skin, thereby discharging the static electricity of the human body and limiting the current flowing through the human body to prevent the risk of electric shock.

[0042] Specifically, the monitoring point of the ESD protection link 20 is connected to the ESD monitor through the ESD monitoring interface 104, so as to realize the connection of the ESD protection link 20 to the ESD monitor. The monitoring point of the ESD protection link refers to a specific test node on the grounding path of the ESD protection link. For example, the anti-static wristband is provided with a connector which can be inserted into the ESD monitoring interface. The edge of the anti-static desk mat is provided with a grounding buckle which can be connected to the ESD monitoring interface through a wire and a plug. The ESD monitoring interface can also be connected to the grounding bolt of the equipment shell through a wire and a plug.

[0043] The detection circuit 103 is connected to the master control chip 102 and the ESD monitoring interface 104, and is used to convert the square wave excitation signal sent by the master control chip into a sawtooth wave voltage signal and apply it to the monitoring point of the external ESD protection link, such as the anti-static wristband interface or the grounding buckle of the desk mat.

[0044] The ADC sampling pin of the master control chip 102 collects the response voltage change generated by the application of the sawtooth wave voltage signal to the monitoring point at a fixed delay time, and obtains the ESD monitoring result of the ESD protection link according to the response voltage change. The response voltage change can reflect the time domain variation characteristics of the monitoring point.

[0045] In one embodiment, the voltage difference between the start time and the delay time of a signal period is inversely proportional to the equivalent impedance, and the equivalent impedance of the protection link is inversely deduced through a calibration curve or formula. According to the equivalent impedance, it can be judged whether the ESD protection link is abnormally grounded. In one embodiment, in the case of electric leakage, the leakage voltage is superimposed on the detection circuit, causing the response voltage at the start time of different signal periods to deviate. By detecting the response voltage difference at the start time of different signal periods, it can be judged whether the ESD protection link has a charge leakage abnormality.

[0046] The ESD monitoring result can include whether the anti-static wristband is normally worn, whether the anti-static wristband is grounded, whether the human body leakage voltage (human body static potential) is normal, whether the equipment shell is grounded, whether the equipment leakage voltage is normal, whether the platform pad is grounded, and whether the platform pad leakage voltage is normal.

[0047] In an embodiment, the master control chip can adopt an STM32 controller. The master control chip provides a hardware basis for processing algorithms. Through an ADC (Analog to Digital Converter) and software processing, continuous analog signals can be converted into digital quantities, and accurate quantitative value calculation can be performed. According to different threshold values, more detailed classification of states can be performed, so that the ESD monitoring result with rich information can be obtained, and rich and effective information can be provided for workers, thereby improving the reliability of ESD protection management.

[0048] The ESD monitoring instrument of the present application, the detection circuit is connected with the ESD monitoring interface and the master control chip, the ESD monitoring interface is connected with the external ESD protection link, the detection circuit is used for converting the square wave excitation signal sent by the master control chip into a sawtooth wave voltage signal and applying the sawtooth wave voltage signal to the monitoring point of the external ESD protection link; the master control chip is used for collecting the response voltage change generated by the sawtooth wave voltage signal applied to the monitoring point, and obtaining the ESD monitoring result of the ESD protection link according to the response voltage change. The response voltage change can reflect the time domain change characteristics of the monitoring point, the interference of the ground potential difference can be avoided, and the ESD monitoring result of the ESD protection link can be obtained based on this. Thus, the intuitive data analysis can replace the analog comparison, and the reliability of ESD detection is improved.

[0049] The inventor of the present application also found that in the actual production process, some employees have weak static electricity protection consciousness and do not start the ESD monitoring instrument actively, which brings hidden dangers to production.

[0050] In view of this problem, as shown in Figures 1 to 4 The ESD monitoring instrument further comprises a human body proximity sensor 105 connected with the master control chip 102, which is used for detecting the human body target in the sensing area.

[0051] The master control chip 102 is used for responding to the human body existence signal output by the human body proximity sensor 105 and controlling the ESD monitoring instrument to be in a standby state.

[0052] The human body proximity sensor 105 is arranged in the shell 101, and the output end thereof can be connected with one pin of the master control chip 102. In an embodiment, the human body proximity sensor 105 can adopt an infrared sensor, a radar sensor or the like. When the human body target is detected in the sensing area, the human body existence signal is sent to the master control chip 102 through the pin.

[0053] The main control chip 102 is configured to enable the detection circuit 103 in response to the human body presence signal output by the human body proximity sensor 105, and control the ESD monitor to be in a standby state.

[0054] In an embodiment, one pin of the main control chip 102 is connected with the enable end or circuit switch of the detection circuit 103. The main control chip 102 is configured to send an enable signal to the enable end or circuit switch of the detection circuit 103 through the pin in response to the human body presence signal output by the human body proximity sensor 105, so as to enable the detection circuit 103 to enter the standby state.

[0055] With the ESD monitor, when the human body target is detected by the human body proximity sensor 105 in the sensing area during the production process, the human body presence signal is sent to the main control chip 102 through the pin, and the main control chip 102 enables the detection circuit 103 to continuously detect the external ESD protection link 20 through the ESD monitoring interface 104.

[0056] The ESD monitor detects the human body presence signal through the human body proximity sensor 105, and then enables the detection circuit 103 to enter the standby state, so as to realize the automatic start of the ESD monitor through the human body proximity sensor 105. The ESD monitor is free from the dependence on manual start operation by personnel, effectively reduces or eliminates the operation omission caused by intentional non-start or forgotten start of the monitor by personnel, ensures that the start rate of the ESD monitor reaches 100%, and ensures that the ESD monitor can effectively play a role in the production process.

[0057] In an embodiment, the shell 101 is provided with a sensing window 1051 for the human body proximity sensor 105 to detect externally. The position of the sensing window 1051 is configured according to the installation height and orientation of the ESD monitor, so that the ESD monitor can detect the human body target. For example, if the installation height of the ESD monitor is low, the sensing window can be provided on the top or front surface of the shell. If the installation height of the ESD monitor is high, the sensing window can be provided on the bottom or front surface of the shell. The front surface refers to the surface of the shell facing the normal partition area of the measured human body (for example, when the user stands or sits in front of the ESD monitor, the orientation of the ESD monitor).

[0058] In this way, the setting position of the sensing window 1051 of the human body proximity sensor 105 can meet the actual demand and accurately capture the human body target.

[0059] In an embodiment, the aperture size of the induction window 1051 is larger than the maximum outer diameter size of the probe head of the human body proximity sensor 105. In this way, mechanical obstruction can be reduced or eliminated, and the effective detection angle of the human body proximity sensor can be expanded, so that the induction field of the human body proximity sensor 105 can completely pass through the induction window 1051.

[0060] In an embodiment, as shown in FIG. 1, the main control chip 102 includes a PWM output pin and an ADC sampling pin. Figure 5

[0061] The detection circuit 103 includes an RC charging and discharging circuit 1031, a resistor voltage dividing network 1032, and a filter circuit 1033. One end of the RC charging and discharging circuit 1031 is connected to the PWM output pin of the main control chip 102, and the other end is connected to the input end of the resistor voltage dividing network 1032. The output end of the resistor voltage dividing network 1032 is connected to the ESD monitoring interface 104, and the voltage dividing node of the resistor voltage dividing network 1032 is connected to the input end of the filter circuit 1033. The output end of the filter circuit 1033 is connected to the ADC sampling pin of the main control chip 102.

[0062] Based on the above detection circuit 103, the main control chip 102 outputs a PWM square wave excitation signal to the RC charging and discharging circuit 1031 through the PWM output pin. The RC charging and discharging circuit 1031 converts the PWM signal into a charging and discharging voltage signal, which is input to the resistor voltage dividing network 1032 for voltage division. The output end of the resistor voltage dividing network 1032 is connected to the ESD monitoring interface 104, and a test current is applied to the ESD monitoring interface through the resistor voltage dividing network 1032. The response voltage of the external ESD protection link 104 can be detected through the voltage dividing node. The response voltage is filtered by the filter circuit 1033 to remove noise, and then sent to the ADC pin of the main control chip 102.

[0063] As shown in FIG. 1, the RC charging and discharging circuit 1031 includes a third capacitor C3 and a fourth resistor R4. One end of the third capacitor C3 is connected to the PWM pin of the main control chip 102, and the other end of the third capacitor C3 is connected to one end of the fourth resistor R4 and also connected to the input end of the resistor voltage dividing network 1032. The other end of the fourth resistor R4 is grounded. Figure 6

[0064] The resistor voltage dividing network 1032 includes a fifth resistor R5 and a sixth resistor R6 connected in series, and the voltage dividing node is between the two resistors. The other end of the sixth resistor R6 is connected to the ESD monitoring interface 104, which is used to connect the external ESD protection link, so that the equivalent impedance Rx of the external ESD protection link is included as part of the equivalent resistance of the charging and discharging circuit.

[0065] ​​The time constant τ of the RC charging and discharging circuit = equivalent resistance (Req) * C3.

[0066] Since the equivalent resistance Req of the RC charging and discharging loop includes the equivalent impedance Rx of the protection link, the change of the equivalent impedance Rx of the protection link will directly cause the change of the equivalent resistance Req of the RC charging and discharging loop, and further change the charging and discharging time constant τ.

[0067] The change of τ will significantly affect the sawtooth waveform output by the RC circuit:

[0068] The increase of the equivalent impedance Rx of the protection link causes the increase of the equivalent resistance Req of the RC charging and discharging loop, and further the increase of the time constant τ. This results in the decrease of the charging and discharging speed, and the decrease of the situation that the capacitor is not charged to the saturation voltage before discharging or not discharged to 0V before charging under the same frequency PWM, and the higher sawtooth amplitude and the more gentle rising / falling edge.

[0069] The decrease of the equivalent impedance Rx of the protection link causes the decrease of the equivalent resistance Req of the RC charging and discharging loop, and further the decrease of the time constant τ. This results in the increase of the charging and discharging speed, and the easier charging of the capacitor to the saturation voltage or discharging to 0V, and the lower sawtooth amplitude and the more steep rising / falling edge.

[0070] Therefore, the equivalent impedance Rx of the external ESD protection link is included in part of the equivalent resistance of the RC charging and discharging loop, and the change of the equivalent impedance Rx of the protection link is used to change the RC charging and discharging time constant τ, so as to change the waveform characteristics of the excitation signal (sawtooth wave). Thus, by detecting the characteristics of the ADC sampling point voltage (caused by the change of the waveform), the resistance value of the equivalent impedance Rx of the external ESD protection link is indirectly measured to judge the reliability of the ESD protection link ground.

[0071] When the PWM square wave excitation signal is high, the current charges the third capacitor C3 through the fourth resistance R4, and when the input square wave is low, the third capacitor C3 discharges through the fourth resistance R4. Under the continuous square wave input, the RC charging and discharging circuit outputs the sawtooth wave voltage, which is then applied to the external ESD protection link connected with the ESD monitoring interface 104 through the resistance dividing network 1032. The response voltage of the external ESD protection link 104 can be detected through the dividing node, and the response voltage is filtered by the filtering circuit 1033 to remove noise and sent to the ADC pin of the main control chip 102 for sampling.

[0072] In an embodiment, the main control chip collects the response voltage generated by the sawtooth voltage signal applied to the monitoring point at the beginning and the delayed time of each signal period to obtain the response voltage change.

[0073] Thus, the fixed delay differential sampling under square wave excitation can be used to detect the equivalent impedance and voltage of the ESD protection link according to the change of the response voltage.

[0074] Specifically, according to the capacitor charging formula V(t) = Vcc·(1-e -t / (RC) )

[0075] wherein R is the equivalent resistance of the RC charging and discharging circuit (including the equivalent impedance of the protection link), and C is the charging and discharging capacitor.

[0076] Further, the equivalent resistance of the RC charging and discharging circuit is decomposed according to the formula, and the equivalent impedance of the ESD protection link is calculated.

[0077] In an embodiment, the response change includes a first voltage difference of the start time and the delay time of the same signal period.

[0078] The host chip calculates the equivalent impedance of the ESD protection link according to the first voltage difference, compares the equivalent impedance with a threshold value, and obtains the ground state of the ESD protection link.

[0079] After the square wave is triggered, the ADC pin of the host chip 102 collects the first voltage difference of the excitation signal at T0 (initial) and T1 (delay) time. Because the voltage difference is inversely proportional to the equivalent resistance, the equivalent impedance of the ESD protection link can be deduced by calibration curve or formula, and the static ring impedance and device resistance can be monitored.

[0080] In an embodiment, the response change includes a second voltage difference of the start time of different signal periods; the host chip compares the second voltage difference with a no-leakage voltage reference value; and when the second voltage difference is greater than the no-leakage voltage reference value, it is determined that the ESD protection link has a charge leakage abnormality.

[0081] The leakage voltage (such as AC voltage of device leakage) will be superimposed on the charging and discharging circuit, causing the reference voltage to deviate at T0 time. By detecting the second voltage difference of the excitation signal at T0 time in different periods, comparing the second voltage difference with the no-leakage voltage reference value, judging the size of the leakage voltage, and further judging whether the protection link has a charge leakage abnormality.

[0082] In an embodiment, according to the actual situation of the factory, the measured no-leakage voltage reference value is 8V, and in the case of no leakage, the electrical difference value of the excitation signal at the T0 moment of the first signal period and at the T0 moment of the second signal period should be the same or very close. When leakage occurs, the leakage voltage (such as the AC voltage of the device leakage) will be superimposed on the charge-discharge circuit, causing the reference voltage at the T0 moment of the next signal period to deviate, and causing the voltage at the T0 moment of the second signal period to be much larger than the voltage at the T0 moment of the first signal period. The second voltage difference between the two is greater than the no-leakage voltage reference value (8V), and it is determined that the corresponding ESD protection link of the interface has a leakage, i.e., a charge leakage abnormality.

[0083] The excitation signal can adopt a square wave signal, which is stable in triggering and avoids direct current drift interference, a small-capacitance capacitor accelerates the charge-discharge speed, and is suitable for high-frequency scenes such as ESD pulse monitoring.

[0084] The detection circuit 103 has simple circuit and low cost, and can realize monitoring of key ESD data.

[0085] As shown in Figure 6 The filter circuit 1033 includes a first resistor R1, a first capacitor C1, a second capacitor C2, a second resistor R2, and a third resistor R3.

[0086] The first end of the first resistor R1 is connected to the voltage division node, and the second end is connected to the first end of the first capacitor C1; the second end of the first capacitor C1 is connected to the first end of the second capacitor C2, and the second end of the second capacitor C2 is grounded; the first end of the second capacitor C2 is also connected to the first end of the second resistor R2, the first end of the third resistor R3, and the ADC sampling pin; the second end of the second resistor R2 is connected to the power supply; and the second end of the third resistor R3 is grounded.

[0087] Among them, the first resistor R1 and the first capacitor C1 and the second capacitor C2 form a low-pass filter, the second resistor R2 and the third resistor R3 form a resistor voltage divider, a direct current bias voltage is established on the ADC sampling pin, and it is ensured that the response voltage signal to be measured falls within the ADC range. The second capacitor C2 is connected in parallel between the ADC input end and the ground, and can effectively filter out high-frequency noise. The use of the filter circuit can improve the sampling quality of the response voltage.

[0088] In an embodiment, as shown in Figures 1 to 3 The ESD monitoring interface includes at least one of the following:

[0089] The first type is at least one first ESD monitoring interface 1041 for connecting an anti-static wrist strap, so that the first ESD monitoring interface 1041 can be connected to the wrist strap discharge link. The wrist strap discharge link includes, in sequence, the skin of an operator, a wrist strap, a cable, and the ground.

[0090] Secondly, at least one second ESD monitoring interface 1042 for connecting a workbench mat or a device. Thus, the second ESD monitoring interface 1041 can be connected to a workbench mat ground link. The workbench mat ground link in turn includes a workbench mat surface, a conductive layer, a ground buckle and the ground. And / or, the second ESD monitoring interface 1041 can be connected to a device ground link. The device ground link in turn includes a device shell, a ground wire, a grounding point and the ground.

[0091] Wherein, the front surface refers to the surface of the shell facing the normal partition area of the measured human body (such as when the user stands or sits in front of the ESD monitor, the surface facing the user). The back surface refers to the surface opposite to the front surface.

[0092] In terms of operation, workers are more likely to plug and unplug the connector of the anti-static wristband from the first ESD monitoring interface 1041, while the plug of the workbench mat or the device shell is usually less required to be plugged and unplugged from the ESD monitoring interface 1042. Therefore, in order to facilitate the operation of workers, the first ESD monitoring interface 1041 is arranged on the front surface of the shell, and the second ESD monitoring interface 1042 is arranged on the back surface of the shell. This layout allows workers to directly view and quickly plug and unplug the wristband connector, while hiding the low-frequency operation ground wire, taking into account the operation efficiency and the neatness of the site.

[0093] In this embodiment, the ESD monitoring interface 104 can include at least one first ESD monitoring interface 1041 for connecting an anti-static wristband, and at least one second ESD monitoring interface 1042 for connecting a workbench mat or a device shell.

[0094] In this way, the wearing of the anti-static wristband, the grounding of the workbench mat and the grounding of the device shell can be monitored. Moreover, the ESD monitor supports the use of a general anti-static wristband, without the need to configure special accessories, further reducing the investment cost of the factory in the direction of ESD protection.

[0095] In an embodiment, as shown in Figure 1 、 Figure 2 、 Figure 3 and Figure 7 The ESD monitor further includes at least one of a differential signal communication module 106, a single-ended signal communication module 107 and a wireless communication module 108, all of which are connected to the main control chip 102. Thus, the ESD monitor is provided with multiple communication modes.

[0096] The differential signal communication module 106 refers to a communication module based on the principle of differential transmission. The signals with opposite phases are transmitted on two cables through complementary voltage signals, and the data transmission is realized by detecting the voltage difference at the receiving end. The differential signal communication module 106 can be an RS485 communication module or a CAN bus communication module.

[0097] The single-ended signal communication module 107 refers to a communication module that transmits signals through a single cable, which is suitable for short-distance and high-efficiency transmission. The single-ended signal communication module 107 can include an RS-232 module and a UART module.

[0098] Specifically, the differential signal communication module 106 includes an RS485 communication chip 1061 arranged in the shell 101, and at least one Type-C interface 1062 arranged on the shell 101 and connected with the RS485 communication chip 1061. The Type-C interface 1062 is arranged on the rear surface of the shell.

[0099] In a specific embodiment, an RS485 communication chip can be used to connect two Type-C interfaces. Based on the RS485 industrial bus standard, combined with the double Type-C interface, long-distance and multi-device networking communication between multiple ESD monitors can be realized. Multiple monitors are connected in series through the RS485 module for communication, so that the data of multiple monitors can be aggregated and transmitted, or remote device control instructions can be received, which meets the large-scale networking needs of factories. The RS485 communication chip uses a differential signal transmission method (anti-interference voltage up to ±12V), and combines with a CHECKSUM verification mechanism (error rate ≤0.001%), to ensure the reliability of long-distance data transmission.

[0100] The single-ended signal communication module 107 includes a serial communication chip 1071 arranged in the shell 101, and at least one Type-B interface 1072 arranged on the shell 101 and connected with the serial communication chip 1071. The Type-B interface 1072 is arranged on the rear surface of the shell.

[0101] Through the Type-B interface 1072 of the serial communication mode, the ESD monitor can be locally connected with a computer or other terminal, which is used for parameter configuration, monitoring data reading and analysis in the development and debugging stage, and facilitates engineers to optimize device performance.

[0102] Taking a network of 20 ESD monitors as an example, 20 sub-machines are connected in series through Type-C interfaces, the host address is set to 0000, and the slave address is allocated as 0001-0020. The host is connected with a local terminal such as a computer through a Type-B interface, sends a networking command to the slave, and allocates the slave address. The slave sends a response to the host through the networking link, and the networking is successful.

[0103] The wireless communication module 108 can be a WIFI communication module, a 4G module, a 5G module, etc. Data is transmitted through a wireless network, and ESD monitoring data can be uploaded to a server / cloud in real time, helping managers remotely and in real time master the protection situation of the production site. Remote server configuration instructions can also be received to promote intelligent and networked management and break free from wired connection restrictions.

[0104] The server can connect the networking of the ESD monitor, for example, the factory networks the ESD monitors on each production line respectively. The server is in communication connection with each networked host, and the server can inquire the grounding state of the production line from the host, and the host reports the grounding state of each machine in the network to the server.

[0105] Based on the above three communication modules, a three-level communication link can be constructed to realize the full-process digital closed loop of ESD protection from configuration to monitoring and then to management. The Type-B interface 1072 and the Type-C interface 1062 with low operation frequency are arranged on the rear surface of the shell, which can optimize cable management, reduce interface loosening caused by user touching, and improve reliability.

[0106] Among them, the local configuration link based on the single-ended signal communication module adopts the combination of USB-to-serial and A55A header protocol, which can quickly complete device parameter configuration. The on-site networking link based on the RS485 communication module is based on the RS485 communication standard and A0 / A1 frame structure protocol, and supports N devices in host-free series networking. The remote transmission link based on the wireless communication module uses ESP8266 WIFI module and AT instruction set protocol to realize cloud synchronization of monitoring data and seamless connection with the MES system.

[0107] In an embodiment, as shown in Figure 1 、 Figure 2 、 Figure 3 and Figure 7 The ESD monitor further comprises:

[0108] a drive chip 109 arranged in the shell 101 and connected with the master control chip 102; and

[0109] at least one multiplexing interface 110 arranged on the shell 101 and connected with the output pin of the drive chip 109; the multiplexing interface 110 is configured as a grounding interface or an external indicator light driving interface, and the multiplexing interface 110 is arranged on the rear surface of the shell.

[0110] Among them, the drive chip is used to drive the related load. In an embodiment, the drive chip adopts A4950T drive chip.

[0111] The multiplexing interface 110 can be used as a grounding interface of the ESD monitor or a driving interface of an external indicator lamp for connecting the external indicator lamp. The external indicator lamp can be installed in a more conspicuous position to facilitate personnel in a remote place or different area to view the status of the external ESD protection link. In an embodiment, the external indicator lamp can be a double-color lamp that displays green in a normal state and red in an abnormal state, thereby being able to quickly indicate the abnormality of ESD protection in the area.

[0112] In the embodiment, the driving chip is used to drive the related load, and the grounding and the double-color lamp interface are matched to enhance the remote visual management effect and protect the stability of the grounding function and the external indicator lamp. The multiplexing interface 110 with low operation frequency is arranged on the rear surface of the shell to optimize the cable management, reduce the interface loosening caused by user touch, and improve the reliability.

[0113] In an embodiment, as shown in FIG. 1, the ESD monitor further includes a sound alarm 111 arranged in the shell 101 and connected with the main control chip 102. When the main control chip 102 detects the ESD protection abnormality of the external ESD protection link, the sound alarm 111 can be driven to issue a sound alarm. Figure 1 、 Figure 2 、 Figure 3 and Figure 7 In an embodiment, the sound alarm 111 uses a buzzer as a sound emitting unit. In the shell, the buzzer corresponds to a specific area outside the shell, and a plurality of holes 1110 are arranged in the specific area to ensure the effective transmission of the sound of the alarm.

[0114] The sound alarm can be configured to prompt different alarm sounds according to different types of abnormalities, so that the type of abnormality can be distinguished from the sound. For example, when the static ring is detected to be worn improperly, the equipment is abnormal, or the voltage is leaked, different alarm prompts such as intermittent sound and continuous sound are issued to strengthen the abnormality warning from the auditory dimension.

[0115] In an embodiment, the ESD monitor further includes a plurality of state indicator lamps 112 arranged on the shell 101 and connected with the main control chip 102. Each state indicator lamp 112 corresponds to one ESD monitoring interface 104 and is used to indicate the state of the external ESD protection link connected with the ESD monitoring interface 104. The state indicator lamps 112 are arranged on the front surface of the shell.

[0116] As shown in FIG. 1, the ESD monitor further includes a plurality of state indicator lamps 112 arranged on the shell 101 and connected with the main control chip 102. Each state indicator lamp 112 corresponds to one ESD monitoring interface 104 and is used to indicate the state of the external ESD protection link connected with the ESD monitoring interface 104. The state indicator lamps 112 are arranged on the front surface of the shell.

[0117] As shown in FIG. 1, the ESD monitor further includes a plurality of state indicator lamps 112 arranged on the shell 101 and connected with the main control chip 102. Each state indicator lamp 112 corresponds to one ESD monitoring interface 104 and is used to indicate the state of the external ESD protection link connected with the ESD monitoring interface 104. The state indicator lamps 112 are arranged on the front surface of the shell. Figures 1 to 3As shown, in the case of two first ESD monitoring interfaces 1041 for connecting anti-static wristbands and two second ESD monitoring interfaces 1042 for connecting a table pad or a device shell, the ESD monitor is configured with four status indicator lights 112, each corresponding to an ESD monitoring interface, for indicating the status of the connected external ESD protection link. To facilitate the production site staff to view, the information of the indicated external ESD protection link can also be marked around the indicator light.

[0118] In an embodiment, the status indication can use a two-color light, which has three display states, namely green, red and off. When the ESD monitor is not turned on, it is off, when the external ESD protection link is not connected or the ESD protection state of the connected external ESD protection link is abnormal, it displays red, and when the ESD protection state of the connected external ESD protection link is normal, it displays green. Thus, the staff can distinguish the state of the ESD protection link of the workstation through the color of the status indicator light.

[0119] In an embodiment, as shown in Figure 1 , Figure 2 , Figure 3 and Figure 7 , the ESD monitor can also include a mechanical switch 113 provided on the front surface of the housing 101 and connected to the main control chip 102, which is used as a control switch of the monitor. The mechanical switch 113 can be a toggle switch. The mechanical switch 113 is provided on the front surface of the housing 101, which is convenient for the user to operate. Through the mechanical switch 113, a hardware level operation mode is provided, which supports manual setting of device operating mode and parameters, such as turning on / off specific monitoring functions, switching monitoring threshold, etc., to flexibly adapt to different production scene requirements.

[0120] In an embodiment, as shown in Figure 1 , Figure 2 , Figure 3 and Figure 7 , the ESD monitor further includes a power management module 114 connected to the main control chip 102, and a power input interface 115 connected to the power management module 114.

[0121] The power input interface 115, as an external power inlet of the device, can use a 12V DC interface for connecting a 12V DC power supply to provide basic power support for the operation of the device.

[0122] The power management module 114 is responsible for device power allocation, conversion and voltage stabilization. It receives 12V DC input power and converts it into 3.3V and 5V voltages required by internal modules such as the main control chip, human proximity sensor and communication chip, to ensure stable power supply to each module.

[0123] AsFigures 1 to 3 As shown, for the convenience of user viewing, the interfaces and switches that need to be frequently operated and used can be arranged on the front surface of the ESD monitor, and the interfaces that are less frequently operated can be arranged on the rear surface opposite to the front surface. In use, the front surface of the ESD monitor faces the worker for operation.

[0124] Specifically, the first ESD monitoring interface 1041 for connecting the anti-static wrist strap, the status indicator light 112, and the mechanical switch 113, which are frequently operated, are arranged on the front surface. The power input interface 115, the Type-C interface 1062, the Type-B interface 1072, the multiplexing interface 110, and the second ESD monitoring interface 1042 for connecting the table mat or equipment, which are less frequently operated, are arranged on the rear surface.

[0125] Specifically, the mechanical switch 113, the plurality of status indicator lights 112, and the first ESD monitoring interface 1041 are arranged in sequence along the length direction of the front surface of the shell. The second ESD monitoring interface 1042, the multiplexing interface 110, the Type-B interface 1072, and the Type-C interface 1062 are arranged in sequence along the length direction of the rear surface of the shell. Thus, the thickness redundancy of the traditional side-by-side layout is eliminated, and the thickness size of the ESD monitor is reduced.

[0126] In an embodiment, the shell 101 includes a first part 1012 and a second part 1011 which are butted along the height direction, the first part includes a top plate 10123, a first end plate 10121 and a second end plate 10122, the first end plate 10121 and the second end plate 10122 are arranged in sequence along the length direction of the shell on one side of the top plate 10123 facing the second part 1011, the second part 1011 includes a bottom plate 10113, a first side plate 10111 and a second side plate 10112, the first side plate 10111 and the second side plate 10112 are arranged in sequence along the width direction of the shell on one side of the bottom plate 10112 facing the first part 1012.

[0127] In this way, the first part 1012 of the shell 101 is a left-right opening U-shaped structure including the top plate 10123, the first end plate 10121 and the second end plate 10122, and the second part 1011 of the shell 101 is a front-rear opening U-shaped structure including the bottom plate 10113, the first side plate 10111 and the second side plate 10112. The first part 1012 and the second part 1011 can be embedded to form a closed structure of the shell, which facilitates the assembly of the shell and improves the assembly efficiency.

[0128] The first part 1012 extends from the docking end to the length direction to form a mounting portion 1013, and the mounting portion is provided with a mounting hole 116, so that the ESD monitor can be fixed through the mounting hole 116 of the mounting portion 1013.

[0129] The ESD monitor of the application combines the detection function of the ESD monitor with the forced function of the human body proximity sensor 105, so as to ensure that the alarm opening rate reaches 100%. By monitoring the ESD protection link of the production station, the ESD failure events caused by non-standard personnel operation and equipment grounding problems are greatly reduced, and the ESD protection level of personnel and equipment is significantly improved. By configuring multiple communication modules, the ESD monitor can provide multiple communication modes and realize multiple communication functions. By setting the sound alarm and the status indicator light, multiple forms of alarm mode are provided through vision and hearing.

[0130] The application also provides an ESD monitoring system, which comprises the ESD monitor 10. Figure 1 More specifically, the ESD monitoring system comprises multiple ESD monitors 10 as shown in the above embodiments, the ESD monitors 10 are arranged at each station on the production line, and are used to connect the ESD protection link at the station through the ESD monitoring interface of the ESD monitor 10; and the ESD monitors are connected in a network based on a preset protocol.

[0131] By connecting the multiple ESD monitors in a network based on the preset protocol, the centralized monitoring and management of the data of the ESD monitor can be realized. In a specific application, the ESD monitors at each station on a production line can be connected in a network, the ESD monitors report the detected ESD data to a host computer, the host computer can be connected to a display device, and then a worker can remotely check the ESD data of each station through the display device.

[0132] In an embodiment, the ESD monitors are connected in a network based on an RS485 bus, and one of the ESD monitors is configured as a host computer, and the other ESD monitors are configured as slave computers.

[0133] Specifically, based on the RS485 communication standard and the A0 / A1 frame structure protocol, multiple devices are connected in a network without a host computer. The independent host computer design can effectively reduce the cost of the device.

[0134] In an embodiment, the ESD monitoring system further comprises a server 30 connected to the host computer. In an embodiment, the host computer uploads the ESD monitoring results of the ESD monitors in the network to the server 30 through a wireless communication module, so as to help the manager to remotely and real-timely master the protection situation of the production site.

[0135] In some embodiments, the host of the ESD monitoring system is also connected with a display device, the server refreshes the real-time grounding state of the external ESD protection link connected by each monitoring instrument in each group network in time and sends it to the host, which is displayed through the display device of the host. Through the display device, the staff can check the real-time state of the external ESD protection link connected by each ESD monitoring instrument on the production line.

[0136] In an embodiment, the ESD monitoring system further comprises a server 30 connected with each ESD monitoring instrument. The monitoring results of each ESD monitoring instrument are uploaded to the server 30, which helps the management personnel to remotely and timely grasp the protection situation of the production site.

[0137] When the traditional monitoring instrument detects the abnormality of the external ESD facility, such as not wearing an anti-static wristband, it usually issues an alarm through the sound alarm or status indicator light of the ESD monitoring instrument. If the monitoring instrument itself is not grounded well, or the sound alarm or status indicator light is abnormal, it cannot trigger an alarm in time, and the leakage voltage of the direct current power supply may damage the production equipment, such as PCBA, through the static ring.

[0138] To solve this problem, in an embodiment, when the server detects that the ESD monitoring result of any monitoring instrument in the network is abnormal, it triggers an alarm of the MES (Manufacturing Execution System) system.

[0139] In simple terms, MES is a set of information systems that connect the management layer (ERP system, etc.) and the operation control layer (PLC, SCADA, equipment) of the production site. In this embodiment, the ESD monitoring instruments form an ESD monitoring system through networking. Each slave ESD monitoring instrument reports the ESD monitoring result to the master ESD monitoring instrument. For example, when the leakage voltage is greater than the threshold value, it sends an abnormal frame (such as A1 0E 00 01 010F 27FF 26 25, where the 3rd byte FF indicates that the voltage exceeds the standard) to the host through the RS485 link, and the host reports the ESD monitoring result to the server. When the server detects that the ESD monitoring result of any monitoring instrument in the network is abnormal, it triggers an alarm of the MES system. Thus, the problem that the traditional ESD monitoring instrument cannot effectively alarm due to poor grounding is effectively solved. Thus, the damage of production equipment caused by grounding problems is effectively avoided, and the damage rate of equipment leakage voltage is reduced.

[0140] The ESD monitor system of the present application successfully breaks through the bottleneck problems of high cost, low efficiency and insufficient intelligence of traditional ESD monitoring through the deep cooperation of multiple modules and the organic integration of innovative detection and communication technology, realizes intelligent management and control of the whole process of production site static protection, and provides a reliable and efficient ESD protection solution for electronic product manufacturing and other industries.

[0141] The present application also provides an ESD monitoring method, which is applied to an ESD monitor and realized through a main control chip of the ESD monitor, as shown in Figure 2 The method comprises the following steps:

[0142] In step 802, a square wave excitation signal is sent to a detection circuit, and the detection circuit converts the square wave excitation signal into a sawtooth wave voltage signal and applies it to a monitoring point of an external ESD protection link.

[0143] Specifically, multiple ESD protection links are usually arranged on the production station to meet the needs of anti-static production. Common ESD protection links include wrist strap discharge links corresponding to anti-static wrist straps, table pad grounding links corresponding to production equipment table pads, and equipment grounding links corresponding to equipment shells.

[0144] The wrist strap discharge link includes, in sequence, an operator's skin, a wrist strap, a cable and the ground.

[0145] The table pad grounding link includes, in sequence, a table pad surface, a conductive layer, a grounding buckle and the ground.

[0146] The equipment grounding link includes, in sequence, an equipment shell, a grounding wire, a grounding point and the ground.

[0147] Personnel grounding facilities and equipment facilities. The personnel grounding facilities include anti-static wrist straps. The anti-static wrist strap is connected in series with the ground through a built-in small resistance value resistor (such as a 1MΩ resistor), and the metal buckle is tightly attached to the skin during use, discharging the static electricity of the human body while limiting the current flowing through the human body to prevent the risk of electric shock.

[0148] The anti-static table pad is grounded through a grounding wire with resistance, used to discharge static electricity around the table top. The equipment shell grounding refers to connecting the equipment shell with the ground through a conductive path, playing a role in preventing electric shock and static electricity.

[0149] Specifically, as shown in Figure 3As shown, the monitoring point of the ESD protection link 20 is connected to the ESD monitor through the ESD monitoring interface 104, so as to connect the ESD protection link 20 to the ESD monitor. The monitoring point of the ESD protection link refers to a specific test node on the grounding path of the ESD protection link. For example, the anti-static wristband is provided with a connector which can be inserted into the ESD monitoring interface. The edge of the anti-static platform pad is provided with a grounding buckle which can be connected to the ESD monitoring interface through a wire and a plug. The ESD monitoring interface can also be connected to the grounding bolt of the equipment shell through a wire and a plug.

[0150] The detection circuit 103 is connected to the master control chip 102 and the ESD monitoring interface 104, and is used to convert the square wave excitation signal sent by the master control chip into a sawtooth wave voltage signal and apply it to the monitoring point of the external ESD protection link, such as the anti-static wristband interface or the grounding buckle of the platform pad.

[0151] In step 804, the response voltage change generated by the application of the sawtooth wave voltage signal to the monitoring point is collected.

[0152] The ADC sampling pin of the master control chip 102 collects the response voltage change generated by the application of the sawtooth wave voltage signal to the monitoring point at a fixed delay, and obtains the ESD monitoring result of the ESD protection link according to the response voltage change. The response voltage change can reflect the time domain variation characteristics of the monitoring point.

[0153] In step 806, the ESD monitoring result of the ESD protection link is obtained according to the response voltage change.

[0154] In an embodiment, the voltage difference between the start time of a signal period and the delay time is inversely proportional to the equivalent resistance, and the equivalent impedance of the protection link is inversely deduced through a calibration curve or formula. In an embodiment, in the case of leakage, the leakage voltage is superimposed on the detection circuit, causing the response voltage at the start time of different signal periods to deviate. By detecting the response voltage difference at the start time of different signal periods, it can be judged whether the ESD protection link has abnormal charge leakage.

[0155] The ESD monitoring result can include whether the anti-static wristband is worn normally, whether the anti-static wristband is grounded, whether the personnel charge (human body static potential to ground) is discharged normally, whether the equipment shell is grounded, whether the equipment charge is discharged normally, whether the platform pad is grounded, and whether the platform pad charge is discharged.

[0156] In an embodiment, the master control chip can use an STM32 controller. The master control chip provides a hardware basis for processing algorithms, and can convert continuous analog signals into digital quantities through an ADC (Analog to Digital Converter) and software processing, and then perform accurate quantitative value calculation, so as to achieve more detailed classification according to different threshold state classification, thereby obtaining an ESD monitoring result with rich information, providing rich and effective information for staff, and improving the reliability of ESD protection management.

[0157] The ESD monitoring method of the application, a detection circuit is connected to an ESD monitoring interface and a master control chip, the ESD monitoring interface is connected to an external ESD protection link, the detection circuit converts a square wave excitation signal sent by the master control chip into a sawtooth wave voltage signal and applies the sawtooth wave voltage signal to a monitoring point of the external ESD protection link; the master control chip collects a response voltage change generated by the sawtooth wave voltage signal applied to the monitoring point; and the ESD monitoring result of the ESD protection link is obtained according to the response voltage change. The response voltage change can reflect the time domain change characteristics of the monitoring point, can avoid the interference of the ground potential difference, and can obtain the ESD monitoring result of the ESD protection link based on this. Thus, data analysis can be used to replace analog comparison, and the reliability of ESD detection is improved.

[0158] In an embodiment, collecting the response voltage change generated by the sawtooth wave voltage signal applied to the monitoring point includes: collecting the response voltage generated by the sawtooth wave voltage signal applied to the monitoring point at a starting moment and a delay moment of each signal period to obtain the response voltage change.

[0159] As shown in Figure 7 The detection circuit 103 converts the square wave excitation signal into a sawtooth wave voltage signal through an RC charging and discharging circuit.

[0160] Specifically, when the PWM square wave excitation signal is at a high level, the current charges the third capacitor C3 through the fourth resistor R4, and when the input square wave is at a low level, the third capacitor C3 discharges through the fourth resistor R4. Under the continuous square wave input, the RC charging and discharging circuit outputs a voltage in the form of a sawtooth wave, and then applies the voltage to the external ESD protection link connected to the ESD monitoring interface 104 through a resistor voltage dividing network 1032. The response voltage of the external ESD protection link 104 can be detected through the voltage dividing node, the response voltage is filtered and processed by a filtering circuit 1033 to remove noise, and is sent to the ADC pin of the master control chip 102 for sampling.

[0161] The master control chip collects the response voltage generated by the sawtooth wave voltage signal applied to the monitoring point at a starting moment and a delay moment of each signal period to obtain the response voltage change.

[0162] Therefore, the equivalent impedance and voltage of the external ESD protection link can be detected according to the change of the response voltage by using the fixed delay differential sampling mode under the square wave excitation.

[0163] Specifically, according to the capacitor charging formula V(t)=Vcc·(1-e -t / (RC) )

[0164] Wherein, R is the equivalent resistance of the RC charging and discharging circuit (including the equivalent impedance of the protection link), and C is the charging and discharging capacitor.

[0165] Further, the equivalent resistance of the RC charging and discharging circuit is decomposed according to the formula, and the equivalent impedance of the ESD protection link is calculated.

[0166] In one embodiment, the response change includes a first voltage difference between a start time and a delay time of the same signal period.

[0167] The ESD monitoring result of the ESD protection link is obtained according to the change of the response voltage, including: calculating the equivalent impedance of the ESD protection link according to the first voltage difference; comparing the equivalent impedance with a threshold to obtain the grounding state of the ESD protection link.

[0168] Specifically, after the square wave is triggered, the ADC pin of the master control chip 102 collects the first voltage difference of the excitation signal at T0 (initial) and T1 (delay) time. Because the voltage difference is inversely proportional to the equivalent resistance (the greater the resistance, the smaller the first voltage difference), the equivalent impedance of the ESD protection link can be monitored by backstepping the ESD protection link through the calibration curve or formula, such as the static ring impedance and the device resistance.

[0169] In one embodiment, the ESD protection link includes at least one of the anti-static wristband discharge link, the table pad grounding link and the device grounding link.

[0170] The grounding state of the ESD protection link is obtained by comparing the equivalent impedance with a threshold, including at least one of:

[0171] If the equivalent impedance of the anti-static wristband discharge link is greater than the calibration value under the no-load condition, it is determined that the anti-static wristband is not worn.

[0172] If the equivalent impedance of the anti-static wristband discharge link is greater than the threshold, or the change rate of the equivalent impedance of the anti-static wristband discharge link is greater than the threshold, it is determined that the anti-static wristband is abnormally grounded.

[0173] If the equivalent impedance of the anti-static wristband discharge link is less than or equal to the threshold, it is determined that the anti-static wristband is normally worn.

[0174] If the equivalent impedance of the workstation ground link is less than or equal to a corresponding threshold value, it is determined that the workstation ground is normal;

[0175] If the equivalent impedance of the workstation ground link is greater than a threshold value, or the rate of change of the equivalent impedance of the equivalent impedance is greater than a threshold value, it is determined that the workstation ground is abnormal;

[0176] If the equivalent impedance of the device ground link is less than or equal to a threshold value, it is determined that the device ground is normal;

[0177] If the equivalent impedance of the device ground link is greater than a corresponding threshold value, or the rate of change of the equivalent impedance of the device ground link is greater than a corresponding threshold value, it is determined that the device ground is abnormal.

[0178] In an embodiment, different threshold values can be set for different types of external ESD protection links, and the equivalent impedance of different ESD protection links is compared with the threshold value corresponding to the type to accurately determine the ESD grounding condition.

[0179] In an embodiment, the smallest value of the threshold value for triggering an alarm for the equivalent impedance of different types of external ESD protection links can be set as the threshold value for triggering an alarm for the ESD monitor to detect ground abnormalities. For example, among the equivalent impedance of the device ground link, the equivalent impedance of the workstation ground link, and the equivalent impedance of the anti-static wristband discharge link, the threshold value (e.g., 10Ω) for triggering an alarm for the equivalent impedance of the device ground link is the smallest, and it is set as the threshold value for triggering an alarm for the ESD monitor to detect ground abnormalities. When any one of the equivalent impedance of the device ground link, the equivalent impedance of the workstation ground link, and the equivalent impedance of the anti-static wristband discharge link is greater than the threshold value for triggering an alarm for the ground abnormality, the ESD monitor triggers an alarm for the ground abnormality, and the specific abnormal type is checked by the staff.

[0180] In the present embodiment, the ground abnormality of the external ESD protection link can be determined by the measured equivalent impedance of the ESD protection link, and can also be determined by the rate of change of the equivalent impedance of the ESD protection link. For example, when the rate of change of the equivalent impedance of the ESD protection link is greater than a threshold value (e.g., 20%), it is determined that the ESD protection link is grounded abnormally. For example, when the equivalent impedance of the ESD protection link suddenly increases from 10MΩ to 15MΩ, it is determined that the ground is abnormal, the master chip controls the status indicator light of the ESD monitor to be red, and the sound alarm is started to continuously alarm.

[0181] The inventors of the present application have also found that the device ground is prone to poor contact due to vibration, and the traditional point inspection method is time-consuming and labor-intensive, relies on manual work, and cannot be monitored in real time. Changes in the state of the device during the inspection are difficult to detect in a timely manner. The static grounding bus and the device grounding bus are limited by the traditional three-point grounding resistance test method, which is complex to operate and difficult to execute. The market devices are also difficult to detect bus abnormalities, which leads to the inability to timely detect the occurrence of leakage voltage.

[0182] In an embodiment, the response change includes a second voltage difference of start times of different signal periods.

[0183] The ESD monitoring result of the ESD protection link is obtained according to the response voltage change, including: comparing the second voltage difference with a no-leakage voltage reference value; and determining that the ESD protection link has a charge leakage abnormality when the second voltage difference is greater than the no-leakage voltage reference value.

[0184] Specifically, a leakage voltage (such as an AC voltage leaked by a device) is superimposed on the charge-discharge loop, causing the reference voltage at T0 to deviate. By detecting the second voltage difference of the excitation signal at T0 in different periods, the second voltage difference is compared with the no-leakage voltage reference value to determine the size of the leakage voltage, and then determine whether the protection link has a charge leakage abnormality.

[0185] In an embodiment, according to the actual situation of the factory, the no-leakage voltage reference value is measured to be 8V. In the case of no leakage, the voltage difference at T0 in the first signal period and at T0 in the second signal period of the excitation signal should be the same or very close. When leakage occurs, a leakage voltage (such as an AC voltage leaked by a device) is superimposed on the charge-discharge loop, causing the reference voltage at T0 to deviate, resulting in a voltage at T0 in the second signal period much larger than a voltage at T0 in the first signal period. The second voltage difference between the two is greater than the no-leakage voltage reference value (8V), and it is determined that the corresponding ESD protection link of the interface has a leakage, i.e., a charge leakage abnormality.

[0186] The excitation signal can be a square wave signal. The square wave signal is stable and avoids direct current drift interference. A small-capacitance capacitor accelerates the charge-discharge speed and adapts to high-frequency scenarios such as ESD pulse monitoring.

[0187] In an embodiment, the ESD protection link includes at least one of a static wrist strap discharge link, a table mat grounding link, and a device grounding link.

[0188] When the second voltage difference is greater than the no-leakage voltage reference value, it is determined that the ESD protection link has a charge leakage abnormality, including at least one of:

[0189] If the second voltage value of the static wrist strap discharge link is greater than the no-leakage voltage reference value, it is determined that the personnel charge leakage is abnormal.

[0190] If the second voltage value of the table mat grounding link is greater than the no-leakage voltage reference value, it is determined that the table mat charge leakage is abnormal.

[0191] If the second voltage value of the device grounding link is greater than the no-leakage voltage reference value, it is determined that the device charge leakage is abnormal.

[0192] In one embodiment, different leakage-free voltage reference values ​​can be set for different types of external ESD protection links. The second voltage difference of different ESD protection links is compared with the leakage-free voltage reference value corresponding to that type to accurately determine whether there is an abnormal charge discharge in the ESD protection link.

[0193] In one embodiment, the threshold for triggering abnormal charge discharge of different types of external ESD protection links can also be used as the threshold for triggering a leakage current alarm on the ESD monitor. For example, among the equipment grounding link, the table mat grounding link, and the anti-static wrist strap discharge link, the threshold for triggering abnormal charge discharge of the anti-static wrist strap discharge link (e.g., 8V) is the smallest. This threshold can be set as the threshold for triggering a leakage current alarm on the ESD monitor. When any one of the second voltage difference of the equipment grounding link, the second voltage difference of the table mat grounding link, and the second voltage difference of the anti-static wrist strap discharge link is greater than the threshold for triggering a leakage current alarm, the leakage current alarm of the ESD monitor is triggered, and the staff can then investigate the specific abnormality type.

[0194] In this embodiment, a hybrid detection technology combining single-wire contact impedance (range 1MΩ-100MΩ) and AC voltage (0-220V) is employed to scan the equipment grounding circuit every 50ms. When the equivalent impedance of any detected ESD protection link exceeds the configured upper threshold (default value 10), the equipment grounding is deemed to have failed. When the human body leakage voltage exceeds the software-configured upper threshold (default value 8V), the electrostatic discharge bus grounding is deemed to have failed, indicating an abnormal discharge of human charge. At this time, the system immediately triggers a continuous audible and visual alarm (red light illuminates and a long beep). The grounding status of the ESD monitor is reported to the server via a USB-to-serial protocol or a WIFI module. Voltage sensitivity parameters can be uploaded in real time using request commands of communication protocols (such as RS485 0x83), overcoming the limitations of traditional inspection methods in monitoring equipment operating status.

[0195] The inventors of this application also discovered that in actual production processes, some employees have a weak awareness of electrostatic protection and do not actively turn on the ESD monitoring device, which poses a potential risk to production.

[0196] Regarding this issue, such as Figures 1 to 3 Figure 1 Figure 2 Figure 3 Figure 7 Figures 1 to 3 Figure 1 Figure 2 Figure 3 Figure 7 Figures 1 to 3 Figure 8 Figure 9 Figures 1 to 4 Figure 6 Figures 1 to 3 As shown, the ESD monitor also includes a human proximity sensor 105 connected to the main control chip 102, used to detect human targets in the sensing area.

[0197] The main control chip 102 is used to respond to the human presence signal output by the human proximity sensor 105 and control the ESD monitor to be in standby mode.

[0198] The human body proximity sensor 105 is arranged in the shell 101, and an output end of the human body proximity sensor 105 can be connected with one pin of the main control chip 102. The shell 101 is provided with an induction window 1051 for the human body proximity sensor 105 to detect outward. In an embodiment, the human body proximity sensor 105 can be an infrared sensor, a radar sensor or the like. When a human body target is detected in the sensing area, a human body existing signal is sent to the main control chip 102 through the pin.

[0199] The ESD monitoring method further comprises: in response to the human body existing signal output by the human body proximity sensor, controlling the ESD monitor to be in a standby state.

[0200] Specifically, the main control chip 102 is configured to enable the detection circuit 103 in response to the human body existing signal output by the human body proximity sensor 105, and control the ESD monitor to be in a standby state.

[0201] In an embodiment, one pin of the main control chip 102 is connected with an enable end or a circuit switch of the detection circuit 103, and the main control chip 102 is configured to send an enable signal to the enable end or the circuit switch of the detection circuit 103 through the pin in response to the human body existing signal output by the human body proximity sensor 105, so as to enable the detection circuit 103 to enter the standby state.

[0202] With the ESD monitor, when a human body target is detected in the sensing area of the human body proximity sensor 105 in the production process, a human body existing signal is sent to the main control chip 102 through the pin, and the main control chip 102 enables the detection circuit 103 to continuously detect the external ESD protection link 20 through the ESD monitoring interface 104.

[0203] The ESD monitor detects the human body existing signal through the human body proximity sensor 105, and then enables the detection circuit 103 to enter the standby state, so as to realize automatic starting of the ESD monitor through the human body proximity sensor 105. The ESD monitor is free from the dependence on manual starting operation of personnel, effectively reduces or eliminates the operation omission caused by intentional non-starting or forgetting to start the monitor by personnel, ensures that the starting rate of the ESD monitor reaches 100%, and ensures that the ESD monitor can effectively play a role in the production process.

[0204] The ESD monitoring method of the present application has the following technical effects:

[0205] 1. Strengthening personnel and equipment.

[0206] Through the organic combination of human body infrared induction and the opening function of the monitoring instrument, the opening rate of the monitoring instrument is ensured to reach 100%. The response time of poor grounding detection is less than 100ms, effectively avoiding the damage of equipment leakage voltage caused by grounding problems, and reducing the leakage voltage damage rate of the equipment to 0%. At the same time, through real-time and accurate monitoring of the static ring and the grounding state of the equipment, the grounding abnormal identification rate reaches 100%, greatly reducing the ESD failure events caused by non-standard personnel operation and equipment grounding problems, and significantly improving the ESD protection level of personnel and equipment.

[0207] 2. Optimized detection efficiency and cost.

[0208] The device has an automatic detection function, and the detection time of a single device is less than 1 second, which greatly improves the detection efficiency. The device uses a design without independent host, which effectively reduces the cost of the device. In addition, the device supports the use of a general anti-static wristband, without the need to equip special accessories, further reducing the investment cost of the factory in ESD protection equipment.

[0209] 3. Intelligent and networked management.

[0210] The multi-protocol cooperative work realizes the "configuration-monitoring-management" digital closed-loop management mode of ESD protection in the production field. Management personnel can remotely configure resistance, voltage and other sensitivity parameters through the MES system with WIFI, reducing on-site debugging time. When the system detects an abnormal state, it can push a work order in real time, making it convenient for management personnel to remotely and efficiently control the ESD protection work in the production field.

[0211] 4. Anti-interference and reliability improvement.

[0212] RS485 differential signal transmission, host and server communication mechanisms, etc. make the data transmission success rate in industrial environment not less than 99.9%, effectively ensuring the accuracy of monitoring data and the stability of system operation, improving the anti-interference ability and reliability of the device in complex industrial environment.

[0213] The present application successfully breaks through the bottleneck problems of high cost, low efficiency and insufficient intelligence of traditional ESD monitoring through the organic integration of multi-module deep cooperation and innovative detection and communication technology, realizes the intelligent management and control of the whole process of electrostatic protection in the production field, provides a reliable and efficient ESD protection solution for electronic product manufacturing and other industries, and has broad market application prospect and significant economic benefits.

[0214] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical scope disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An ESD monitor, characterized by, The ESD monitor further comprises a human body proximity sensor connected with the master control chip, and the human body proximity sensor is used for detecting a human body target in a sensing area. The master control chip is used for responding to a human body existence signal output by the human body proximity sensor, and controlling the ESD monitor to be in a standby state. The master control chip comprises a PWM output pin and an ADC sampling pin. The detection circuit comprises an RC charging and discharging module, a resistance voltage dividing network and a filter circuit; one end of the RC charging and discharging module is connected with the PWM output pin of the master control chip, the other end is connected with an input end of the resistance voltage dividing network, an output end of the resistance voltage dividing network is connected with the ESD monitoring interface, and a voltage dividing node of the resistance voltage dividing network is connected with an input end of the filter circuit; and an output end of the filter circuit is connected with the ADC sampling pin of the master control chip. The master control chip collects a response voltage generated by the sawtooth wave voltage signal applied to the monitoring point at a starting moment and a delay moment of each signal period, and obtains the response voltage change.

2. The ESD monitor of claim 1, wherein, The response change comprises a first voltage difference of the starting moment and the delay moment of the same signal period, and the ESD monitoring result comprises a grounding state. The master control chip calculates an equivalent impedance of the ESD protection link according to the first voltage difference, compares the equivalent impedance with a threshold value, and obtains the grounding state of the ESD protection link.

3. The ESD monitor of claim 1, wherein, The ESD monitoring result comprises whether a charge leakage is abnormal, the response change comprises a second voltage difference of the starting moment of different signal periods, the master control chip compares the second voltage difference with a no-leakage voltage reference value, and determines that the ESD protection link has the charge leakage abnormality when the second voltage difference is greater than the no-leakage voltage reference value. The ESD monitoring system comprises a plurality of ESD monitors as claimed in any one of claims 1 to 6, which are arranged at workstations on a production line and are used for connecting ESD protection links at the workstations through ESD monitoring interfaces of the ESD monitors.

4. The ESD monitor of any one of claims 1 to 3, wherein, The ESD monitors are interconnected based on a preset protocol.

5. The ESD monitor of claim 4, wherein, The ESD monitoring system further comprises a server connected with the ESD monitors; the ESD monitors report the ESD monitoring results to the server; and the server triggers an MES system alarm when detecting that the ESD monitoring result of any one of the ESD monitors in the network is abnormal. The method is applied to an ESD monitor, and the method comprises:

6. The ESD monitor of claim 4, wherein, ​ 7. An ESD monitoring system, characterized by ​ ​ 8. The ESD monitoring system of claim 7, wherein, ​ 9. An ESD monitoring method, characterized by, ​ The square wave excitation signal is sent to a detection circuit, which converts the square wave excitation signal into a sawtooth voltage signal and applies it to a monitoring point of an external ESD protection link; The response voltage change generated by the sawtooth voltage signal applied to the monitoring point is collected; According to the response voltage change, the ESD monitoring result of the ESD protection link is obtained.

10. The ESD monitoring method of claim 9, wherein, The method further comprises: In response to the human presence signal output by the human body proximity sensor, the ESD monitor is controlled to be in a standby state.

11. The ESD monitoring method of claim 9, wherein, Collecting the response voltage change generated by the sawtooth voltage signal applied to the monitoring point comprises: At the beginning time and the delay time of each signal period, the response voltage generated by the sawtooth voltage signal applied to the monitoring point is collected to obtain the response voltage change.

12. The ESD monitoring method of claim 11, wherein, The response change includes a first voltage difference between the beginning time and the delay time of the same signal period; The ESD monitoring result includes a ground state; According to the response voltage change, the ESD monitoring result of the ESD protection link is obtained, comprising: According to the first voltage difference, the equivalent impedance of the ESD protection link is calculated; The equivalent impedance is compared with a threshold value to obtain the ground state of the ESD protection link.

13. The ESD monitoring method of claim 11, wherein, The response change includes a second voltage difference between the beginning times of different signal periods; the ESD monitoring result includes whether there is a charge leakage abnormality; According to the response voltage change, the ESD monitoring result of the ESD protection link is obtained, comprising: The second voltage difference is compared with a no-leakage voltage reference value; When the second voltage difference is greater than the no-leakage voltage reference value, it is determined that the ESD protection link has a charge leakage abnormality.

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