A detection circuit for testing multi-wavelength multi-power PDs
By designing a multi-wavelength, multi-power PD detection circuit, and utilizing MCU control and relays to achieve automated detection of different wavelength bands and power levels, the problem of limited wavelength response range and power range in existing technologies has been solved, and efficient detection of wide-wavelength and multi-power lasers has been realized.
Patent Information
- Application Number
- CN202521818728.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-26
- Publication Date
- 2026-08-25
- Estimated Expiration
- 2035-08-26
AI Technical Summary
Existing PD detection circuits cannot simultaneously achieve flexible detection of wide-wavelength and multi-power lasers on a single device, and suffer from problems such as limited wavelength response range, limited power range, and insufficient flexibility.
A detection circuit was designed, comprising an MCU control chip, a photoelectric conversion module, a photoelectric conduction module, a voltage divider adjustment module, and a voltage follower module. The circuit achieves flexible switching between different frequency bands and power levels through multiple photoelectric conversion sub-circuits and a voltage divider adjustment module, and realizes automated detection by using MCU unified control and relays.
It enables the detection of lasers in a wide wavelength range from 400nm to 1700nm, supports multi-level detection from low power to high power, improves detection flexibility and accuracy, reduces hardware costs and testing time, reduces signal interference, and improves detection efficiency and system reliability.
Smart Images
Figure CN224682352U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optoelectronic detection and measurement technology, and in particular to a detection circuit for testing multi-wavelength, multi-power PDs. Background Technology
[0002] Photodiodes (PDs) are widely used in lasers, optical communications, and spectral detection, and their main function is to convert optical signals into electrical signals. Existing PD detection circuits typically include a photoelectric conversion unit, a sampling resistor, and an operational amplifier follower circuit. A bias voltage drives the PD to output a stable photocurrent, which is then converted into a voltage signal by the sampling resistor. Finally, the operational amplifier connects to the microcontroller's ADC interface to achieve PD value detection.
[0003] However, existing technologies have the following shortcomings: (1) Limited wavelength response range: A single PD can only cover optical signals in a specific wavelength band. When the test equipment needs to cover a wider wavelength range, it is necessary to add different types of PDs or replace the test equipment, which increases the cost and operational complexity.
[0004] (2) Limited power range: When converting photoelectric signals, the voltage range of the single sampling resistor is limited by the ADC of the microcontroller, and the resistance value selection is limited. When the power of the light source under test changes greatly, it is difficult for the existing technology to realize multi-power level detection.
[0005] (3) Insufficient flexibility: The existing PD detection circuit has a simple structure and cannot flexibly switch the PD or sampling resistor according to the wavelength and power of the light source being tested, resulting in low detection efficiency and cumbersome operation.
[0006] Therefore, existing technologies cannot simultaneously meet the laser detection requirements of wide wavelength and wide power on a single testing device. There is an urgent need for a new type of detection circuit that can flexibly select the PD and power range and improve detection accuracy and efficiency. Summary of the Invention
[0007] This application provides a detection circuit for testing multi-wavelength, multi-power PDs, to solve the problem in the prior art that it is impossible to simultaneously achieve flexible detection and high-precision measurement of wide-wavelength, multi-power lasers on a single device.
[0008] In a first aspect, this application provides a detection circuit for testing multi-wavelength, multi-power PDs, the circuit comprising: The MCU control chip includes a signal output terminal and a signal detection terminal. The signal output terminal is used to output control signals, and the signal detection terminal is used to detect the PD value of the photodiode under test. A photoelectric conversion module includes multiple photoelectric conversion sub-circuits, each of which includes a photodiode under test, wherein each photodiode under test is used to convert an optical signal in one of the wavelength ranges into an electrical signal. The photoelectric conduction module includes photoelectric conduction sub-circuits that correspond one-to-one with each photoelectric conversion sub-circuit. Each photoelectric conduction sub-circuit includes a first coupling terminal, a second coupling terminal, and a control terminal. The control terminal of each of the photoelectric conduction sub-circuits is coupled to the signal output terminal of the MCU control chip, and the first coupling terminal of each of the photoelectric conduction sub-circuits is coupled to the corresponding photoelectric conversion sub-circuit. The voltage divider regulation module includes a switching unit and multiple independent branches, with at least one voltage divider resistor connected in series in each independent branch. The photoelectric conduction sub-circuit is used to conduct in response to the control signal of the MCU, so that the photoelectric conversion module is coupled to the voltage divider adjustment module through the corresponding conducted photoelectric conduction sub-circuit; The input terminal of the switching unit is coupled to the signal output terminal of the MCU control chip, so as to determine the corresponding independent branch from multiple independent branches and couple it to the second coupling terminal of each of the photoelectric conduction sub-circuits in response to the control signal of the MCU.
[0009] Optionally, the photoelectric conversion sub-circuit includes a resistor-capacitor unit and a photodiode under test; The input terminal of the resistor-capacitor unit is coupled to the output terminal of the bias voltage, and the output terminal is coupled to the cathode of the photodiode under test. The anode of the photodiode under test is coupled to the first coupling terminal of the corresponding photoconducting sub-circuit.
[0010] Optionally, the RC unit includes a first capacitor, a first resistor, and a second capacitor; the input terminal of the first capacitor is coupled to the output terminal of the bias voltage, and the output terminal is grounded; The input terminal of the first resistor is coupled to the output terminal of the bias voltage, and the output terminal is coupled to the cathode of the photodiode under test and the input terminal of the second capacitor, respectively. The anode of the photodiode under test is coupled to the first coupling terminal of the photoconducting sub-circuit; The output terminal of the second capacitor is grounded.
[0011] Optionally, the photoelectric conduction sub-circuit is a relay.
[0012] Optionally, the signal output terminals of the MCU control chip include a first signal output terminal and a second signal output terminal; The first signal output terminal is coupled to the control terminal of each of the photoelectric conduction sub-circuits and is used to transmit a first control signal to the control terminal of each of the photoelectric conduction sub-circuits. The second signal output terminal is coupled to the input terminal of each of the switching units and is used to transmit a second control signal to the control terminal of each of the photoelectric conduction sub-circuits.
[0013] Optionally, the circuit further includes a switching module, which includes a control signal input terminal and a control signal output terminal; The control signal input terminal is coupled to the first signal output terminal of the MCU control chip, and the control signal output terminal is coupled to the control terminal of each of the photoelectric conduction sub-circuits; The switching module is used to respond to the first control signal output from the first signal output terminal to control the corresponding photoelectric conduction sub-circuit to close, so that the photoelectric conversion sub-circuit is coupled to the voltage divider adjustment module through the corresponding conducting photoelectric conduction sub-circuit.
[0014] Optionally, the switching module includes a switching unit and a third capacitor, and the switching unit further includes an ENABLE pin, a COM pin, and the third capacitor; The COM pin is coupled to the input terminal of the third capacitor; The output terminal of the third capacitor is grounded. The ENABLE pin is grounded.
[0015] Optionally, the switching unit further includes a VCC pin, an ENABLE pin, a GND pin, multiple voltage divider resistor coupling terminals, a signal input terminal, and a fourth capacitor; The VCC pin is coupled to the input terminal of the fourth capacitor; The output terminal of the fourth capacitor is grounded. The ENABLE pin and the GND pin are respectively grounded; Each of the voltage divider resistors is coupled to its corresponding independent branch, and at least one voltage divider resistor is connected in series in each independent branch. The signal input terminal is coupled to the second signal output terminal and is used to respond to the second control signal transmitted from the second signal output terminal to determine the corresponding independent branch from multiple independent branches and couple it to the second coupling terminal of each of the photoelectric conduction sub-circuits.
[0016] Optionally, the circuit may further include a voltage follower module; The input terminal of the voltage follower module is coupled to the output terminal of the voltage divider adjustment module, and the output terminal is coupled to the signal detection terminal of the MCU control chip. The voltage follower module is used to isolate the voltage divider adjustment module from the MCU control chip.
[0017] Optionally, the voltage follower module includes a second resistor, a fifth capacitor, a follower, and a sixth capacitor; The input terminal of the second resistor is coupled to the output terminal of the voltage divider adjustment module, and the output terminal is coupled to the input terminal of the fifth capacitor. The output terminal of the fifth capacitor is grounded; The input terminal of the follower is coupled to the output terminal of the second resistor, and the output terminal is coupled to the signal detection terminal; The input terminal of the sixth capacitor is coupled to the follower, and the output terminal is grounded.
[0018] This invention achieves the detection of lasers with a wide wavelength range from 400nm to 1700nm by setting up multiple PD photoelectric conversion sub-circuits with different wavelength ranges and selecting the corresponding PD by a photoelectric conduction module, thus avoiding the need to design separate detection equipment for different wavelength bands. By setting up multiple independent branches and voltage divider resistors of different values through a voltage divider adjustment module, the range can be flexibly switched according to the power of the light source under test, realizing multi-level detection from low power to high power, significantly improving detection flexibility and accuracy. Integrating multi-wavelength selection and multi-power level adjustment functions into a single circuit structure reduces the number of test devices, saving hardware costs and test space. Unified control of PD selection and voltage divider switching by an MCU avoids manual replacement of components or switching of equipment, shortening test preparation time and improving production and testing efficiency. The voltage follower module isolates the voltage divider adjustment module from the MCU signal detection terminal, effectively reducing signal interference and ensuring stable and reliable data acquisition. Attached Figure Description
[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.
[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.
[0022] Figure 1 A schematic diagram of a module structure for testing a multi-wavelength, multi-power PD, provided in an embodiment of this application; Figure 2 This is a schematic diagram of a specific implementation circuit for testing multi-wavelength, multi-power PDs, provided in an embodiment of this application. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0024] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.
[0025] Combination Figure 1 and Figure 2 The following is a description of the electronic components in the circuit of this utility model: First capacitor (C1), first resistor (R1), second capacitor (C2), photodiodes under test (PD1-PD3), bias voltage (Vr), relays (K1-K3), switching unit (U1), switching unit (U2), voltage divider resistors (R4-R19), third capacitor (C3), second resistor (R2), fifth capacitor (C5), sixth capacitor (C6), and follower (U3A). Note that PD1, PD2, and PD3 can sense light with different wavelengths. For example, PD1 detects 400-700nm, PD2 detects 700-1000nm, and PD3 detects 1000-1700nm. In practical applications, different detection wavelengths of PDs can be selected according to requirements, and the example is not limited to this specific example.
[0026] Figure 1 This is a schematic diagram of a detection circuit for testing multi-wavelength, multi-power PDs, provided in an embodiment of this application.
[0027] This embodiment discloses a detection circuit for testing multi-wavelength, multi-power photodiodes (PDs). Its purpose is to achieve flexible and reliable measurement of PDs with different wavelengths and power levels in a single circuit structure. The detection circuit is based on an MCU control chip. The MCU has a signal output terminal for outputting control signals and a signal detection terminal for sampling. The photoelectric conversion module consists of several photoelectric conversion sub-circuits. Each sub-circuit contains a photodiode to be tested, which is used to convert the optical signal of the corresponding band into an electrical signal. The photoelectric conduction module is equipped with a corresponding conduction sub-circuit for each photoelectric conversion sub-circuit. The conduction sub-circuit has a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal is electrically connected to its respective photoelectric conversion sub-circuit, and the control terminal is coupled to the signal output terminal of the MCU. The voltage divider adjustment module includes a switching unit and multiple independent branches. Each independent branch is connected in series with at least one voltage divider resistor to form different voltage division ratios to adapt to different power ranges. The circuit internally connects the conduction photoelectric conversion sub-circuit to the voltage divider branch selected by the MCU through functional coupling. The voltage after voltage division is acquired by voltage follower or directly by the signal detection terminal of the MCU for subsequent processing.
[0028] In practical implementation, during the power-on or initialization phase, the MCU configures each control pin and ADC channel, preparing to receive commands from the host computer or automatically select the measured photodiode and power range according to internal logic. During measurement, the MCU first sends a first control signal to the control terminal of the corresponding photoelectric conduction sub-circuit based on the operating wavelength of the light source being measured, switching the corresponding conduction sub-circuit from an off state to a conduction state, thereby connecting the selected photodiode to the downstream voltage divider adjustment circuit through the conduction sub-circuit. Subsequently, the MCU outputs a second control signal to the switching unit of the voltage divider adjustment module. Based on this, the switching unit selects a branch with a predetermined voltage division ratio from multiple independent branches, establishing an electrical connection between the voltage divider resistor network of the selected branch and the second connection terminal of the already conducted photoelectric conversion sub-circuit, forming a complete current-to-voltage conversion and voltage divider circuit.
[0029] After the path is established, the PD under test generates a photocurrent under the action of bias and incident light. This photocurrent forms a corresponding voltage divider on the selected voltage divider network. The MCU samples this voltage divider using an ADC at its signal detection terminal and converts the sampled value into the corresponding optical power or PD characteristic parameters according to a pre-calibrated conversion relationship. After the measurement is completed, the MCU can disconnect the conduction sub-circuit or switch to other voltage divider branches and PDs as needed, continuously or intermittently testing PDs of different wavelengths and power ranges without manual replacement of components, thereby achieving automated testing of multiple wavelengths and power levels.
[0030] For example, such as Figure 2 As shown, Figure 2This is a schematic diagram of a specific implementation circuit for testing multi-wavelength, multi-power PDs, provided in an embodiment of this application.
[0031] Furthermore, in this embodiment, the photoelectric conversion sub-circuit consists of a resistor-capacitor unit and a photodiode under test. One end of the resistor-capacitor unit is electrically coupled to the output terminal of the bias voltage Vr to provide reverse bias to the photodiode under test. The output terminal of the resistor-capacitor unit is electrically connected to the cathode of the photodiode under test, while the anode of the photodiode under test is connected to the first connection terminal of the corresponding photoelectric conduction sub-circuit through a wire.
[0032] This RC unit decouples and transiently filters the bias source on the bias side, enabling the measured PD to maintain a stable operating point and output a stable photocurrent under incident light. When the corresponding photoconduction sub-circuit is turned on, the PD's anode potential is introduced into the downstream voltage divider adjustment module, realizing current-to-voltage conversion and range switching. This integrated configuration of the RC unit and PD not only ensures the PD's bias stability and anti-interference capability but also provides repeatable and calibrable electrical conditions for selecting the subsequent voltage divider ratio, thereby improving measurement consistency and accuracy across different ranges.
[0033] Furthermore, this embodiment further defines the above-mentioned RC unit, which includes a filtering and current limiting network composed of a first capacitor, a first resistor, and a second capacitor. One end of the first capacitor is connected to the output terminal of the bias voltage Vr, and the other end is grounded to suppress high-frequency noise from the bias source. One end of the first resistor is also connected to the bias voltage Vr, and its other end is connected to both the cathode of the photodiode under test and the input terminal of the second capacitor. The output terminal of the second capacitor is grounded, thereby forming a low-pass filter and decoupling locally at the PD cathode and limiting the transient peak value of the PD operating current.
[0034] This specific wiring method, in engineering implementation, maintains the cleanliness of the bias source and establishes a stable local operating point at the PD, reducing the possibility of external interference coupling into the measurement point via the bias path. The resulting benefits include: reduced measurement noise, improved signal-to-noise ratio at low power levels, and enhanced protection for the PD and subsequent circuits during high-power switching, thus enabling the system to obtain reliable measurement results across a wide power range.
[0035] Furthermore, in this embodiment, the photoelectric conduction sub-circuit uses a mechanical relay to achieve physical on / off switching and isolation. Specifically, the anode of each photoelectric conversion sub-circuit is connected to the second connection terminal of the voltage divider adjustment module via relay contacts. The relay coil terminal serves as the control terminal of the conduction sub-circuit, driven directly by the control signal output by the MCU or via a driver stage. When the MCU issues a conduction command, the relay engages, connecting the corresponding PD to the voltage divider network; when the MCU issues a disconnect command, the relay disconnects to achieve electrical isolation. The relay can be a G5V-1-5VDC model.
[0036] The implementation of using relays as conducting elements has significant advantages in high-power or measurement scenarios requiring explicit electrical isolation: the physical contacts of relays can provide reliable isolation and withstand voltage performance, the intuitive state of the contacts during switching is helpful for fault diagnosis, and the relays can protect the PD and subsequent circuits by disconnecting before and after measurement, thereby improving the safety and reliability of the overall system.
[0037] Furthermore, in this embodiment, the MCU control chip is configured to have at least two types of signal output terminals. The first signal output terminal group is responsible for transmitting the first control signal to the control terminal of each photoelectric conduction sub-circuit to select or switch the PD path, and the second signal output terminal group is responsible for transmitting the second control signal to the input terminal of the switching unit to select the specific independent branch in the voltage divider adjustment module.
[0038] In the actual measurement process, the MCU follows the control sequence of first selecting the PD and then selecting the voltage divider branch: First, the conducting sub-circuit except for the target PD is placed in the off state through the first signal output terminal, and only the conducting sub-circuit corresponding to the target PD is turned on; then, the switching unit is controlled through the second signal output terminal to select the appropriate voltage divider branch to match the expected power level; finally, the ADC sampling of the signal detection terminal is started.
[0039] This serialization control strategy can effectively avoid the risks of missampling and ADC overvoltage during switching, and simplifies the MCU's software logic and hardware wiring by distinguishing between the two types of control signals, thereby improving measurement safety and system controllability.
[0040] Furthermore, in this embodiment, the system further includes a switch module as an intermediary control unit between the MCU and the photoelectric conduction sub-circuit. The switch module has a control signal input terminal and a control signal output terminal. The control signal input terminal is coupled to the first signal output terminal of the MCU, and the control signal output terminal is connected to the control terminal or its drive stage of the photoelectric conduction sub-circuit. The switch can be a ULN2001DS relay driver chip, wherein 1C, 2C, and 3C are respectively connected to the control terminals SEL_1, SEL_2, and SEL_3 of the photoelectric conduction sub-circuit (relays K1, K2, and K3), and 1B, 2B, and 3B are respectively connected to the first signal output terminal of the MCU control chip in response to the first control signal issued by the MCU.
[0041] The first control signal from the MCU is received by the ULN2001DS switching module, buffered, and distributed before driving each conducting sub-circuit. This indirectly controls the relays to achieve centralized or grouped control of multiple PD channels. Using a switching module reduces the I / O resources directly occupied by the MCU, provides necessary electrical isolation and decoupling, reduces transient interference on the control lines, and makes reliable management of a large number of channels possible in an integrated measurement system, thereby improving system scalability and maintenance convenience.
[0042] Furthermore, in this embodiment, to improve the stability of the switching module during dynamic control, the switching module specifically includes a switching unit and a third capacitor. The switching unit has an ENABLE pin and a COM pin. The COM pin is connected to the input terminal of the third capacitor, the output terminal of the third capacitor is grounded, and the ENABLE pin is grounded to keep the switch in an enabled state.
[0043] The third capacitor is connected in parallel between the COM pin and ground for local decoupling and transient energy buffering, suppressing spikes and oscillations generated by the switch under frequent switching or external interference, thereby ensuring better electrical cleanliness of the control signal before it is transmitted to the conduction sub-circuit. The benefits of this configuration are: reduced malfunctions caused by control signal jitter, improved stability in high-frequency switching scenarios, and simplified system management of the switch enable signal.
[0044] Furthermore, in this embodiment, the structure of the switching unit is further clarified as including a VCC pin, an ENABLE pin, a GND pin, a multi-path voltage divider resistor connection terminal, a signal input terminal, and a fourth capacitor. The VCC pin is connected to the input terminal of the fourth capacitor, and the output terminal of the fourth capacitor is grounded to achieve decoupling of the power supply terminal of the switching unit. The ENABLE pin and the GND pin are grounded to meet the enable and reference ground requirements of the switching device. Each voltage divider resistor connection terminal is connected to the corresponding independent branch (i.e., the voltage divider branch composed of R4 to R19, etc.). The signal input terminal is coupled to the second signal output terminal of the MCU to respond to the second control signal to determine and couple the target branch from multiple independent branches to the second connection terminal of the conduction sub-circuit.
[0045] The switching unit effectively suppresses transient noise caused by power coupling during branch switching and ensures the stability of the voltage divider output by implementing local decoupling (fourth capacitor) at the power and ground terminals and a strict grounding strategy. This improves the repeatability and measurement accuracy of range switching and reduces the probability of measurement anomalies caused by branch switching. The switching unit can use the MAX4617CUE+ model, where the X pin is connected to the photoelectric conduction sub-circuit, the A, B, and C pins are connected to the second signal output terminal of the MCU control chip to respond to the second control signal, and the X0-X7 pins are connected to the voltage divider resistors.
[0046] Furthermore, to protect the voltage division accuracy of the voltage divider adjustment module and reduce the load on the voltage divider network at the ADC input, a voltage follower module is configured at the output of the voltage divider adjustment module as an isolation and buffer unit. The input of the voltage follower module is connected to the output of the voltage divider adjustment module, and its output is connected to the signal detection terminal of the MCU. The voltage follower module includes a second resistor, a fifth capacitor, a follower (unity-gain buffered operational amplifier, as described in the implementation), and a sixth capacitor. The follower can be an AD823ARZ model.
[0047] Specifically, the voltage divider output first passes through the second resistor into the fifth capacitor to implement front-end low-pass filtering and decoupling. The filtered signal drives the input of the follower, and the follower output directly drives the ADC input of the MCU. A sixth capacitor is connected in parallel to the follower output side and grounded to suppress high-frequency noise and oscillation at the output.
[0048] The beneficial effects of this structure are multifaceted: Firstly, the front-end RC filter reduces the impact of high-frequency interference on the measured values, improving measurement stability at low power levels. Secondly, the high input impedance and low output impedance provided by the follower isolate the mutual influence between the voltage divider network and the ADC, protecting the voltage division ratio from being disrupted by changes in the ADC input impedance, ensuring reading consistency and repeatability across different ranges, thereby significantly improving the linear response and accuracy of the measurement system over a wide power range. Furthermore, this isolation structure also helps reduce the system's sensitivity to external interference, improving its robustness in real-world industrial measurement environments.
[0049] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.
[0050] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.
[0051] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.
[0052] In the embodiments provided in this application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling or direct coupling or communication connection may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.
[0053] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.
[0054] In summary, this invention constructs a complete, controllable, and repeatable measurement link from light incidence to ADC reading through techniques such as multi-detector paralleling, on-demand conduction, programmable voltage division, bias and filtering protection, voltage buffer isolation, and serialized control. These structural and control strategies collectively result in: wide band and wide power coverage, improved measurement accuracy and anti-interference capability, enhanced equipment safety, significantly improved automation and operational efficiency, and good scalability for easy calibration and engineering application. This fully demonstrates the practicality and industrial applicability of this implementation scheme compared to existing solutions.
[0055] The embodiments described above are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.
Claims
1. A detection circuit for testing multi-wavelength, multi-power PDs, characterized in that, The circuit includes: The MCU control chip includes a signal output terminal and a signal detection terminal. The signal output terminal is used to output control signals, and the signal detection terminal is used to detect the PD value of the photodiode under test. A photoelectric conversion module includes multiple photoelectric conversion sub-circuits, each of which includes a photodiode under test, wherein each photodiode under test is used to convert an optical signal in one of the wavelength ranges into an electrical signal. The photoelectric conduction module includes photoelectric conduction sub-circuits that correspond one-to-one with each photoelectric conversion sub-circuit. Each photoelectric conduction sub-circuit includes a first coupling terminal, a second coupling terminal, and a control terminal. The control terminal of each of the photoelectric conduction sub-circuits is coupled to the signal output terminal of the MCU control chip, and the first coupling terminal of each of the photoelectric conduction sub-circuits is coupled to the corresponding photoelectric conversion sub-circuit. The voltage divider regulation module includes a switching unit and multiple independent branches, with at least one voltage divider resistor connected in series in each independent branch. The photoelectric conduction sub-circuit is used to conduct in response to the control signal of the MCU, so that the photoelectric conversion module is coupled to the voltage divider adjustment module through the corresponding conducted photoelectric conduction sub-circuit; The input terminal of the switching unit is coupled to the signal output terminal of the MCU control chip, so as to determine the corresponding independent branch from multiple independent branches and couple it to the second coupling terminal of each of the photoelectric conduction sub-circuits in response to the control signal of the MCU.
2. The detection circuit according to claim 1, characterized in that, The photoelectric conversion sub-circuit includes a resistor-capacitor unit and a photodiode under test; The input terminal of the resistor-capacitor unit is coupled to the output terminal of the bias voltage, and the output terminal is coupled to the cathode of the photodiode under test. The anode of the photodiode under test is coupled to the first coupling terminal of the corresponding photoconducting sub-circuit.
3. The detection circuit according to claim 2, characterized in that, The RC unit includes a first capacitor, a first resistor, and a second capacitor; the input terminal of the first capacitor is coupled to the output terminal of the bias voltage, and the output terminal is grounded. The input terminal of the first resistor is coupled to the output terminal of the bias voltage, and the output terminal is coupled to the cathode of the photodiode under test and the input terminal of the second capacitor, respectively. The anode of the photodiode under test is coupled to the first coupling terminal of the photoconducting sub-circuit; The output terminal of the second capacitor is grounded.
4. The detection circuit according to claim 1, characterized in that, The photoelectric conduction sub-circuit uses a relay.
5. The detection circuit according to claim 1, characterized in that, The signal output terminals of the MCU control chip include a first signal output terminal and a second signal output terminal. The first signal output terminal is coupled to the control terminal of each of the photoelectric conduction sub-circuits and is used to transmit a first control signal to the control terminal of each of the photoelectric conduction sub-circuits. The second signal output terminal is coupled to the input terminal of each of the switching units and is used to transmit a second control signal to the control terminal of each of the photoelectric conduction sub-circuits.
6. The detection circuit according to claim 5, characterized in that, The circuit also includes a switching module, which includes a control signal input terminal and a control signal output terminal. The control signal input terminal is coupled to the first signal output terminal of the MCU control chip, and the control signal output terminal is coupled to the control terminal of each of the photoelectric conduction sub-circuits; The switching module is used to respond to the first control signal output from the first signal output terminal to control the corresponding photoelectric conduction sub-circuit to close, so that the photoelectric conversion sub-circuit is coupled to the voltage divider adjustment module through the corresponding conducting photoelectric conduction sub-circuit.
7. The detection circuit according to claim 6, characterized in that, The switching module includes a switching unit and a third capacitor. The switching unit also includes an ENABLE pin, a COM pin, and a third capacitor. The COM pin is coupled to the input terminal of the third capacitor; The output terminal of the third capacitor is grounded. The ENABLE pin is grounded.
8. The detection circuit according to claim 5, characterized in that, The switching unit also includes a VCC pin, an ENABLE pin, a GND pin, multiple voltage divider resistor coupling terminals, a signal input terminal, and a fourth capacitor; The VCC pin is coupled to the input terminal of the fourth capacitor; The output terminal of the fourth capacitor is grounded. The ENABLE pin and the GND pin are respectively grounded; Each of the voltage divider resistors is coupled to its corresponding independent branch, and at least one voltage divider resistor is connected in series in each independent branch. The signal input terminal is coupled to the second signal output terminal and is used to respond to the second control signal transmitted from the second signal output terminal to determine the corresponding independent branch from multiple independent branches and couple it to the second coupling terminal of each of the photoelectric conduction sub-circuits.
9. The detection circuit according to claim 1, characterized in that, The circuit also includes a voltage follower module; The input terminal of the voltage follower module is coupled to the output terminal of the voltage divider adjustment module, and the output terminal is coupled to the signal detection terminal of the MCU control chip. The voltage follower module is used to isolate the voltage divider adjustment module from the MCU control chip.
10. The detection circuit according to claim 9, characterized in that, The voltage follower module includes a second resistor, a fifth capacitor, a follower, and a sixth capacitor; The input terminal of the second resistor is coupled to the output terminal of the voltage divider adjustment module, and the output terminal is coupled to the input terminal of the fifth capacitor. The output terminal of the fifth capacitor is grounded; The input terminal of the follower is coupled to the output terminal of the second resistor, and the output terminal is coupled to the signal detection terminal; The input terminal of the sixth capacitor is coupled to the follower, and the output terminal is grounded.