Weak current acquisition circuit and electronic equipment

Abstract

The invention provides a weak current acquisition circuit and electronic equipment, which are applied to the field of control or regulation systems, and the circuit converts an input current signal to be processed into a corresponding first voltage signal through a first analog switch, a second analog switch and sampling resistors corresponding to different gear control signals; the operation integration unit is used for amplifying the first voltage signal and generating an integration voltage signal, and then the analog-to-digital conversion unit is used for converting the integration voltage signal into a digital voltage signal; a control unit collects the digital voltage signal and calculates a target current value corresponding to the current signal to be processed according to the digital voltage signal. The circuit provided by the embodiment of the invention can be used for amplifying the current signal to be processed, carrying out analog-to-digital conversion on the integral voltage signal and acquiring the corresponding digital voltage signal according to the preset digital filtering algorithm, and can effectively reduce the influence of noise on the acquisition precision in the weak current acquisition process.

Description

Technical Field

[0001] The present application relates to the field of control or regulation systems, and in particular to a weak current acquisition circuit and electronic equipment. Background Art

[0002] In the semiconductor manufacturing process, the ion implanter is one of the key process equipment, which changes the physical properties of semiconductor materials by injecting ion beams into them. In order to accurately determine the dose of ion beam implantation, the industry often uses a dose measurement system to measure the ion beam, especially the Faraday cup in the dose measurement system to measure the current intensity of the ion beam, which makes the accuracy of dose measurement directly affect the quality of the wafer and the product quality rate.

[0003] However, the current signal collected by the Faraday cup is often relatively weak, and existing collection solutions for the current signal collected by the Faraday cup usually have the problem of low accuracy. Summary of the invention

[0004] In view of this, the embodiments of the present application provide a weak current acquisition circuit and an electronic device to achieve accurate acquisition of the current signal collected by the Faraday cup of the ion implanter dose measurement system, thereby further improving the measurement accuracy of the ion implanter dose measurement system.

[0005] In a first aspect, an embodiment of the present application provides a weak current acquisition circuit, the circuit comprising: a first analog switch, a second analog switch, a plurality of sampling resistors, a control unit, an operation integration unit, and an analog-to-digital conversion unit; wherein: The first analog switch and the second analog switch are respectively operated under the action of the gear control signal sent by the control unit, and the connected current signal to be processed is converted into a corresponding first voltage signal through the sampling resistors corresponding to the different gear control signals, and the first voltage signal is input into the operation integration unit; The operational integration unit is used to amplify the input first voltage signal and generate an integrated voltage signal under the discharge action of the constant current source module, and input the integrated voltage signal into the analog-to-digital conversion unit, so that the analog-to-digital conversion unit converts the integrated voltage signal into a digital voltage signal; The control unit is used to collect the digital voltage signal according to a preset digital filtering algorithm, and calculate the target current value corresponding to the current signal to be processed according to the collected digital voltage signal.

[0006] Optionally, in some embodiments, the control unit is further used to: The target current value is compared with a preset current threshold value to determine whether the current measurement range is appropriate. If not, a new gear control signal is sent to the first analog switch and the second analog switch respectively.

[0007] Optionally, in some embodiments, the first analog switch and the second analog switch are intelligent single-pole double-throw switches, the input end of the first analog switch is connected to the current signal to be processed, the first output end of the first analog switch is connected to the first input end of the second analog switch, the second output end of the first analog switch is connected to the second input end of the second analog switch, and the output end of the second analog switch is connected to the input end of the operational integration unit.

[0008] Optionally, in some embodiments, the operational integration unit includes: a first operational amplifier, a second operational amplifier and an integral capacitor, a sampling resistor is connected between the output end of the first operational amplifier and the first input end of the second operational amplifier, the integral capacitor is connected in parallel between the first input end of the second operational amplifier and the output end of the second operational amplifier, and the amplification processing of the input first voltage signal and the generation of an integral voltage signal under the discharge action of the constant current source module include: The first operational amplifier amplifies the first voltage signal to obtain a second voltage signal; the second voltage signal is charged by the integrating capacitor, or discharged under the action of the constant current source module, and the second operational amplifier amplifies the second voltage signal to obtain a third voltage signal; The integrated voltage signal is generated based on the voltage signal output by the integrating capacitor and the third voltage signal.

[0009] Optionally, in some embodiments, the circuit further comprises: a logic control module, wherein the constant current source module switches on or off the circuit connection with the input end of the integral capacitor in response to an on instruction or a off instruction issued by the logic control module; The charging process of the second voltage signal by the integrating capacitor or the discharging process under the action of the constant current source module includes: The second voltage signal is charged when the circuit connection between the integral capacitor and the constant current source module is disconnected, or discharged when the circuit connection between the integral capacitor and the constant current source module is connected.

[0010] Optionally, in some embodiments, the logic control module is specifically configured to send the start instruction to the constant current source module when the integrated voltage signal meets a preset integrated voltage threshold, so that the constant current source module discharges the integrated capacitor.

[0011] Optionally, in some embodiments, the control unit is an FPGA, and the logic control module is a set of logic control units in the FPGA.

[0012] Optionally, in some embodiments, the logic control module is used to send the shutdown instruction to the constant current source module after the integral capacitor is discharged.

[0013] Optionally, in some embodiments, the first output end of the first analog switch is connected to the first end of the first sampling resistor, the second output end of the first analog switch is connected to the first end of the second sampling resistor, the second end of the first sampling resistor and the second end of the second sampling resistor are both grounded, wherein the resistance value of the first sampling resistor is different from the resistance value of the second sampling resistor.

[0014] In a second aspect, an embodiment of the present application provides an electronic device, wherein the electronic device includes a device body and a weak current collection circuit as described in the first aspect and arranged in the device body.

[0015] Beneficial effects of this application: The present application provides a weak current acquisition circuit and an electronic device, which are applied to the field of control or regulation systems. The circuit converts an input current signal to be processed into a corresponding first voltage signal through a first analog switch, a second analog switch and sampling resistors corresponding to different gear control signals, and then uses an operational integration unit to amplify the first voltage signal and generate an integral voltage signal under the discharge action of a constant current source module. Then, the analog-to-digital conversion unit converts the integral voltage signal into a digital voltage signal, and the control unit acquires the digital voltage signal and calculates the target current value corresponding to the current signal to be processed based on the digital voltage signal.

[0016] The circuit provided in the embodiment of the present application is selected to amplify the current signal to be processed, perform analog-to-digital conversion on the integrated voltage signal, and collect the corresponding digital voltage signal according to a preset digital filtering algorithm, which can effectively reduce the influence of noise on the collection accuracy during the weak current collection process. When the current signal to be processed is the current signal collected by the Faraday cup in the dose measurement system of the ion implanter, the current signal collected by the Faraday cup of the dose measurement system of the ion implanter can be accurately collected, thereby further improving the measurement accuracy of the dose measurement system of the ion implanter. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Further details, features and advantages of the present application are disclosed in the following description of exemplary embodiments in conjunction with the accompanying drawings, in which: Figure 1 A circuit connection schematic diagram of a weak current collection circuit provided by the present application is shown; Figure 2 Another circuit connection schematic diagram of the weak current collection circuit provided by the present application is shown. DETAILED DESCRIPTION

[0018] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present application. It should be understood that the drawings and embodiments of the present application are only for exemplary purposes and are not intended to limit the scope of protection of the present application.

[0019] It should be understood that the various steps described in the method embodiments of the present application can be performed in different orders and / or in parallel. In addition, each embodiment may include additional steps and / or omit the steps shown. The scope of the present application is not limited in this respect.

[0020] In order to improve the acquisition accuracy of the current signal output by the Faraday cup in the dose measurement system of the ion implanter, thereby improving the measurement accuracy of the dose measurement system of the ion implanter, the present application provides a weak current acquisition circuit and an electronic device, wherein, in the first aspect, the present application provides a weak current acquisition circuit. In some possible embodiments, it can be as follows Figure 1 As shown, the weak current acquisition circuit may include the following parts: A first analog switch, a second analog switch, a plurality of sampling resistors, a control unit, an operation integration unit, an analog-to-digital conversion unit, and a constant current source module.

[0021] The first analog switch and the second analog switch are connected to the control unit, and both the first analog switch and the second analog switch can receive the gear control signal sent by the control unit. The first analog switch and the second analog switch can respectively act under the action of the gear control signal sent by the control unit, that is, the first analog switch and the second analog switch can perform corresponding work in response to the gear control signal sent by the control unit. The action of the analog switch specifically refers to changing the connection state between the switch contacts.

[0022] As an implementation mode, the first analog switch and the second analog switch are intelligent single-pole double-throw switches, that is, one switch includes three contact points, and the specific circuit connection state of the first analog switch and the second analog switch can be changed by changing the connection state between the contacts. Specifically, in the embodiment of the present application, the current input end of the intelligent single-pole double-throw switch is collectively referred to as the input end, and the current outflow end is collectively referred to as the output end, wherein the number of input ends and output ends can be flexibly designed depending on the actual process design, and the present application does not make a strict limitation.

[0023] Among them, Figure 2 As shown, the first analog switch may be an input terminal and two output terminals (respectively a first output terminal and a second output terminal), and the second analog switch may be two input terminals (respectively a first input terminal and a second input terminal) and one output terminal. Specifically, the input terminal of the first analog switch is connected to the current signal to be processed, the first output terminal of the first analog switch is connected to the first input terminal of the second analog switch, and the second output terminal of the first analog switch is connected to the second input terminal of the second analog switch. The output terminal of the second analog switch is connected to the input terminal of the arithmetic integration unit.

[0024] In an embodiment of the present application, the gear control signal sent by the control unit specifically changes the circuit access state of the first analog switch and the second analog switch. Different circuit access states of the first analog switch and the second analog switch correspond to different resistance values ​​of the connected sampling resistors, and thus the corresponding current collection ranges are different. That is to say, in some embodiments, changes in the access states of the first analog switch and the second analog switch will change the corresponding connected sampling resistors, and there is a correlation between the sampling resistors and the gear control signal. Therefore, the connected current signal to be processed can be converted into the corresponding first voltage signal with the help of sampling resistors corresponding to different gear control signals. Among them, it can be as follows Figure 2 As shown, the control unit sends different gear control signals to the first analog switch and the second analog switch. Specifically, the first gear control signal is sent to the first analog switch, and the second gear control signal is sent to the second analog switch.

[0025] Specifically, in some possible embodiments, Figure 2As shown, the sampling resistor in the weak current acquisition circuit provided in the embodiment of the present application includes: a first sampling resistor R1 and a second sampling resistor R2, wherein the first output end of the first analog switch is connected to the first end of the first sampling resistor, and the second output end of the first analog switch is connected to the first end of the second sampling resistor, wherein the second ends of the first sampling resistor and the second sampling resistor are grounded, and the resistance value of R1 is not the same as the resistance value of R2. According to Ohm's law, the smaller the resistance value of the resistor, the larger the range of the corresponding voltage signal, that is, different gear control signals correspond to different acquisition ranges, and different acquisition ranges are negatively correlated with the resistance value of the sampling resistor. In this way, the current signal can be converted into a first voltage signal of different ranges with the help of sampling resistors with different resistance values.

[0026] For example, Figure 2 As an example, if the resistance of R2 is 10 times that of R1, then when the input terminal of the first analog switch and the first output terminal of the first analog switch are closed, the first voltage signal U correspondingly converted after the sampling resistor R1 is connected is R1 When the input terminal of the first analog switch and the second output terminal of the first analog switch are closed, the first voltage signal U is obtained after the sampling resistor R2 is connected. R2 Between: U R1 / U R2 = 10. In this way, the same current signal to be processed can be converted into the first voltage signal of different gears.

[0027] Among them, the specific gear position to be adopted depends on the gear position control signal output by the control unit. As an implementation method, the control unit is connected to the host computer, and the control unit is used to receive various types of control instructions sent by the host computer, and send the corresponding control instructions to the corresponding circuit module or device. Based on this, the gear position control signal can be a control instruction input by the operator in the host computer, which is used to switch the collection gear position of the weak current collection current. At this time, the control unit can send the control instruction to the corresponding first analog switch and the second analog switch, and the first analog switch and the second analog switch perform corresponding actions to realize the switching of the range gear.

[0028] In the embodiment of the present application, the output end of the second analog switch is connected to the operational integration unit, and the operational integration unit can be used to amplify the first voltage signal output by the output end of the second analog switch and generate an integrated voltage. As an implementation, the operational integration unit can be subdivided into: an operational amplification unit and an integration unit, wherein the operational integration unit can be Figure 2As shown, the transport amplification unit includes: a first operational amplifier U1, a second operational amplifier U2 and a third sampling resistor R3, and the integration unit includes: an integration capacitor C. The connection relationship between the various parts is: the third sampling resistor R3 is connected between the output end of the first operational amplifier and the first input end of the second operational amplifier. The integration capacitor C is connected in parallel between the first input end of the second operational amplifier and the output end of the second operational amplifier.

[0029] In the embodiment of the present application, the first operational amplifier and the second operational amplifier can be regarded as using a two-stage operational amplifier to amplify the first voltage signal, with the first operational amplifier performing preliminary amplification and then further increasing the gain of the amplifier with the help of the second operational amplifier, thereby obtaining a higher voltage amplification factor. In this way, the weak current signal can be amplified or reduced, thereby improving the subsequent high-precision measurement of the weak current signal.

[0030] Since the input impedance of the operational amplifier is high and the output impedance is relatively low, directly connecting the first operational amplifier to the second operational amplifier may cause the second voltage signal to be distorted after directly entering the second operational amplifier. Therefore, in the embodiment of the present application, by setting the third sampling resistor between the first operational amplifier and the second operational amplifier, the impedance matching between the first operational amplifier and the second operational amplifier can be achieved, which can help ensure that the second voltage signal can be transmitted stably and accurately. In addition, the third sampling resistor can also realize the conversion of the current change output by the first operational amplifier into a voltage change. In the embodiment of the present application, the second voltage signal refers to the voltage signal obtained by sampling the output of the first operational amplifier and then on the third sampling resistor. In this way, the current change output by the first operational amplifier can be converted into the corresponding second voltage signal, which can help the second-stage operational amplifier to perform further amplification processing.

[0031] It is worth noting that in the embodiments of the present application, the models, electrical parameter sizes, physical volumes, etc. of the operational amplifiers, analog switches, and sampling resistors can be flexibly selected based on actual experience, and the present application does not impose strict limitations.

[0032] On this basis, the amplification processing of the input first voltage signal by the operational integration unit and the generation of the integrated voltage signal under the discharge action of the constant current source module specifically include: The first operational amplifier amplifies the first voltage signal to obtain a second voltage signal, the second voltage signal is then charged by the integrating capacitor, the second operational amplifier amplifies the second voltage signal to obtain a third voltage signal, and finally an integrated voltage signal is generated based on the voltage signal output by the integrating capacitor and the third voltage signal.

[0033] In an embodiment of the present application, an integral capacitor is located between the first input terminal and the output terminal of the second-stage operational amplifier, and is used to generate an integral voltage signal, wherein the process of generating the integral voltage signal can be regarded as a process of performing an integral operation by the integral capacitor. In other words, the integral capacitor is a core component for performing an integral operation, and when the input second voltage signal is a step voltage, the resistance value of the uncharged integral capacitor is extremely small, thereby allowing the maximum current to flow through the third sampling resistor. As the integral capacitor is charged, the impedance corresponding to the integral capacitor gradually increases, thereby generating a linearly increasing ramp output voltage, so that the input second voltage signal can be integrated and converted into an output voltage, and at this time, the third voltage signal output by the second operational amplifier will be proportional to the integral of the input second voltage signal.

[0034] In addition, the integrating capacitor is in parallel with the second operational amplifier and can also play a filtering role, which can help filter out high-frequency interference signals in the second voltage signal, and further help improve the acquisition accuracy of the entire weak current acquisition circuit.

[0035] During the process of charging the second voltage signal by the integral capacitor, if the entire charging process lasts for a long time, the amount of charge that can be stored in the integral capacitor will approach saturation, which will cause the integral voltage signal output by the operational integration unit to no longer change, and the integral voltage that no longer changes will not be able to reflect the actual situation of the current value output by the current Faraday cup. Therefore, in some possible embodiments, in order to ensure that the integral capacitor accurately performs charging and discharging processing, the integral capacitor is discharged through a constant current source module in the embodiment of the present application, that is, the entire process of generating an integral voltage signal by the operational integration unit requires the discharge action of the constant current source module to generate an accurate integral voltage signal. In addition, the weak current acquisition circuit provided in the present application also includes: a logic control module, wherein the connection relationship between the logic control module and the constant current source module and other parts of the circuit can be as shown below. Figure 2 As shown, the logic control module is connected to the constant current source module. In addition, the logic control module is also connected to the integral capacitor, and the constant current source module is connected to the input end of the integral capacitor. Specifically, the constant current source module responds to the opening instruction or closing instruction issued by the logic control module to connect or disconnect the circuit connection between the input end of the integral capacitor. At this time, the integral capacitor is specifically used for: When the circuit connection with the constant current source module is disconnected, the second voltage signal is charged, or when the circuit connection with the constant current source is connected, the second voltage signal is discharged. Specifically: As an implementation mode, the above-mentioned voltage signal based on the output of the integral capacitor and the third voltage signal generates an integral voltage signal, which can be understood as an integral voltage generating unit formed by the third sampling resistor, the integral capacitor and the second operational amplifier. The input signal passes through the third sampling resistor and then flows to the integral capacitor through feedback. At this time, if the initial charge of the capacitor is 0, it means that the integral capacitor is charged, and the impedance of the integral capacitor gradually increases with time. At this time, the charging current decreases, and the voltage generated at both ends of the capacitor increases slowly, thereby forming a linearly increasing ramp output voltage. The ramp output voltage continues to increase until the capacitor is fully charged.

[0036] As an implementation method, the logic control module can control the constant current source module to connect the circuit connection with the integral capacitor at a specific time, and then flow into the integral capacitor through the constant current source module to discharge the integral capacitor. After the integral capacitor is discharged, a closing instruction is sent to the constant current source module, and the constant current source module closes the circuit connection with the integral capacitor according to the closing instruction. Among them, the specific time can be flexibly set according to the process production requirements. This application does not force a specific time. For example, it can be periodic or specified by the operator on the host computer.

[0037] As another embodiment, an integral voltage threshold is provided in the logic control module, and the logic control module is specifically used to send an opening instruction to the constant current source module when the integral voltage signal meets the preset integral voltage threshold, such as when it is greater than the preset integral voltage threshold, so as to control the constant current source module to discharge the integral capacitor. Specifically, a comparator can be provided in the logic control module, and the integral voltage signal is compared with the preset integral voltage threshold by means of the comparator. If it is greater than the preset integral voltage threshold, an opening instruction is sent to the constant current source module. Among them, the preset integral voltage threshold can be set according to the actual process processing requirements, and is not strictly limited here. In this way, the charge stored on the integral capacitor is released by the constant current source module, which can ensure that the integral capacitor can accurately reflect the current output by the Faraday cup.

[0038] In this way, the embodiment of the present application is selected to show significant advantages when it is necessary to measure the current that changes continuously over time. Specifically, the scheme uses an integral capacitor to integrate and accumulate the dynamic current, effectively realizing the smoothing of noise while ensuring the integrity of the information, that is, no information is lost and distorted during the entire sampling period. Therefore, the total charge amount in a time period calculated by this method, compared with the method of accumulating after point-by-point acquisition, not only has higher accuracy, but also can more truly reflect the actual changes in the current in the time period.

[0039] In an embodiment of the present application, the constant current source module may be a power supply module including multiple constant current sources, for providing multiple stable current sources with different current ranges. Wherein, as an implementation method, since the constant current source module can provide a stable current source, the constant current source module can be regarded as a quantization standard for current acquisition in different ranges in the entire weak current acquisition circuit. The stable current source output by the constant current source module is discharged through an integral capacitor at regular intervals, and a standard integral voltage signal in the form of a triangular wave is output, and then the standard integral voltage signal is converted to a digital signal by an analog-to-digital conversion module, and a reference digital voltage signal under different ranges can be obtained. According to the law of conservation of charge, the current current value is calculated by the integral voltage value, the constant current source value, and the time of discharge.

[0040] As an implementation method, Figure 2 As shown, the output terminal of the second operational amplifier is connected to an analog-to-digital conversion unit, and the function of the analog-to-digital conversion unit is, as the name implies, to perform analog-to-digital conversion on the input signal, that is, to convert the integrated voltage signal output by the second operational amplifier, which is essentially an analog signal, into a digital voltage signal. The analog-to-digital conversion unit is connected to the control unit, and the analog-to-digital conversion unit is used to convert the integrated voltage signal into a corresponding digital voltage signal according to the conversion accuracy specified by the control unit or according to the conversion accuracy supported by the control unit, so that the control unit performs data calculation according to the digital voltage signal.

[0041] In the embodiment of the present application, the control unit is the core control device of the entire weak current acquisition circuit, and the specific functions that the control unit needs to provide are: logic control function, gear control function, signal acquisition and processing function. In the embodiment of the present application, the control unit can be subdivided into several logic control units, and each logic control unit implements the above-mentioned logic control function, gear control function, signal acquisition and processing function. Among them, the logic control unit is a concept at the software level, which is pre-defined by the operator through programming.

[0042] Based on this, in the embodiment of the present application, the logic control unit responsible for realizing the logic control function in the control unit is packaged as the above-mentioned logic control module, that is to say, the logic control module is actually a set of logic control units in the control unit. Similarly, the logic control unit responsible for realizing the gear control function can be packaged as a gear control module, and the logic control unit responsible for realizing the signal acquisition and processing function can be packaged as a signal acquisition and processing module. As an implementation method, the control unit can be an FPGA (Field Programmable Gate Array), and the above-mentioned logic control module can be a software logic running in the FPGA, which is composed of small software sub-logics, and one software sub-logic corresponds to a logic control unit. Among them, in the embodiment of the present application, each logic control unit is a software logic written to the control unit by an operator or user through the host computer of the control unit to run.

[0043] In the embodiment of the present application, a digital filtering algorithm is pre-written in the control unit, and the pre-written digital filtering algorithm is a preset digital filtering algorithm. The control unit can collect and calculate the input digital voltage signal, and at the same time, the input digital voltage signal can be filtered by the preset digital filtering algorithm, which can effectively filter out the high-frequency noise in the digital voltage signal, and help improve the collection accuracy and stability of the entire current collection circuit. Among them, the preset digital filtering algorithm can be flexibly designed and pre-set in the FPGA according to actual process requirements, and the present application does not strictly limit the specific algorithm content of the preset digital filtering algorithm.

[0044] On this basis, in the embodiment of the present application, the control unit is used to collect the digital voltage signal converted by the analog-to-digital conversion module according to the preset digital filtering algorithm, and calculate the target current value corresponding to the current signal to be processed according to the collected digital voltage signal. As described above, the control unit can generate a corresponding gear control signal according to the control instruction input by the operator. As another embodiment, the control unit can compare the target current value with the preset current threshold value to determine whether the current measurement range is appropriate. If not, it is necessary to switch the corresponding measurement range gear. At this time, the control unit can send a new gear control signal to the first analog switch and the second analog switch to change the current measurement range gear, thereby ensuring the accuracy of the target current value corresponding to the current signal to be processed.

[0045] Specifically, as an example, if the target current value collected by the control unit is greater than the upper limit value of the range corresponding to the current measurement range gear, it indicates that the current measurement range is not suitable and a larger measurement range needs to be used for measurement. In this way, the sampling resistors connected to the first analog switch and the second analog switch can be controlled, such as connecting sampling resistors with larger resistance values, so as to change the measurement range from a small range to a large range. Then the current signal is amplified, integrated, and digitally filtered again to accurately measure the target current signal and improve the measurement accuracy of the entire weak current acquisition circuit. And it can achieve fast measurement range gear switching without the user being sensitive, which can more accurately match the range of the measured current and greatly improve the measurement resolution.

[0046] This fast gear change mechanism is called stepless shifting mechanism in this article. It is not a simple range switching, but the logic control module in the FPGA cooperates with the analog switch to enable the circuit to maintain the optimal measurement resolution within the continuously changing current range, which helps to improve the accuracy and flexibility of the measurement. In addition, the preset digital filtering algorithm in the FPGA can help suppress noise while enhancing the collected signal, and also help improve the accuracy of weak current signal acquisition.

[0047] In the second aspect, the present application provides an electronic device including the weak current acquisition circuit. In the second aspect, the electronic device includes a device body and the weak current acquisition circuit described in the first aspect built into the electronic device. The type of the electronic device includes but is not limited to: industrial computers, personal computers, industrial measuring equipment, industrial control machines, servers, etc. As a preferred embodiment, the type of the electronic device may be a dose measurement device that matches the ion implanter. Through the electronic device provided by the present application, with the help of its built-in weak current acquisition circuit, the current signal output by the Faraday cup used for measurement in the ion implanter can be amplified, the integrated voltage signal analog-to-digital conversion, digital filtering and other processing can be performed, which can effectively reduce the influence of noise on the acquisition accuracy during the weak current acquisition process, improve the acquisition accuracy of the current signal output by the Faraday cup, and thus improve the measurement accuracy of the dose measurement system of the ion implanter.

[0048] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". Relevant definitions of other terms will be given in the description below. It should be noted that the concepts of "first", "second", etc. mentioned in this application are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0049] It should be noted that the modifications of "one" and "plurality" mentioned in the present application are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

Claims

1. A weak current collection circuit, characterized in that: The circuit comprises: a first analog switch, a second analog switch, a plurality of sampling resistors, a control unit, an operation integration unit, an analog-to-digital conversion unit, and a constant current source module; wherein: The first analog switch and the second analog switch are respectively operated under the action of the gear control signal sent by the control unit, and the connected current signal to be processed is converted into a corresponding first voltage signal through the sampling resistors corresponding to the different gear control signals, and the first voltage signal is input into the operation integration unit; The operational integration unit is used to amplify the input first voltage signal and generate an integrated voltage signal under the discharge action of the constant current source module, and input the integrated voltage signal into the analog-to-digital conversion unit, so that the analog-to-digital conversion unit converts the integrated voltage signal into a digital voltage signal; The control unit is used to collect the digital voltage signal according to a preset digital filtering algorithm, and calculate the target current value corresponding to the current signal to be processed according to the collected digital voltage signal.

2. The circuit according to claim 1, characterized in that The control unit is further used for: The target current value is compared with a preset current threshold value to determine whether the current measurement range is appropriate. If not, a new gear control signal is sent to the first analog switch and the second analog switch respectively.

3. The circuit according to claim 1, characterized in that The first analog switch and the second analog switch are intelligent single-pole double-throw switches, the input end of the first analog switch is connected to the current signal to be processed, the first output end of the first analog switch is connected to the first input end of the second analog switch, the second output end of the first analog switch is connected to the second input end of the second analog switch, and the output end of the second analog switch is connected to the input end of the arithmetic integration unit.

4. The circuit according to claim 1, characterized in that The operational integration unit includes: a first operational amplifier, a second operational amplifier and an integral capacitor, a sampling resistor is connected between the output end of the first operational amplifier and the first input end of the second operational amplifier, the integral capacitor is connected in parallel between the first input end of the second operational amplifier and the output end of the second operational amplifier, and the first voltage signal is amplified and the integral voltage signal is generated under the discharge action of the constant current source module, including: The first operational amplifier amplifies the first voltage signal to obtain a second voltage signal; the second voltage signal is charged by the integrating capacitor, or discharged under the action of the constant current source module, and the second operational amplifier amplifies the second voltage signal to obtain a third voltage signal; The integrated voltage signal is generated based on the voltage signal output by the integrating capacitor and the third voltage signal.

5. The circuit according to claim 4, characterized in that The circuit further comprises: a logic control module, wherein the constant current source module switches on or off the circuit connection with the input end of the integral capacitor in response to an on instruction or a off instruction issued by the logic control module; The charging process of the second voltage signal by the integrating capacitor or the discharging process under the action of the constant current source module includes: The second voltage signal is charged when the circuit connection between the integral capacitor and the constant current source module is disconnected, or discharged when the circuit connection between the integral capacitor and the constant current source module is connected.

6. The circuit according to claim 5, characterized in that The logic control module is specifically configured to send the start instruction to the constant current source module when the integrated voltage signal meets a preset integrated voltage threshold, so that the constant current source module discharges the integrated capacitor.

7. The circuit according to claim 5, characterized in that The control unit is an FPGA, and the logic control module is a set of logic control units in the FPGA.

8. The circuit according to claim 5, characterized in that The logic control module is used to send the closing instruction to the constant current source module after the integral capacitor is discharged.

9. The circuit according to claim 3, characterized in that A first output end of the first analog switch is connected to a first end of a first sampling resistor, a second output end of the first analog switch is connected to a first end of a second sampling resistor, a second end of the first sampling resistor and a second end of the second sampling resistor are both grounded, wherein a resistance value of the first sampling resistor is different from a resistance value of the second sampling resistor.

10. An electronic device, characterized in that: The electronic device comprises a device body and a circuit as described in any one of claims 1 to 9 arranged in the device body.

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