Testing device of optical device
By designing an optical device test device that containing a lower -voltage circuit and a clamp circuit, the problem that the test device cannot be used normally when there is no external power supply, and the adaptability and stability of different power conditions are realized.
Patent Information
- Application Number
- CN202420030278.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-05
- Publication Date
- 2025-01-24
- Estimated Expiration
- 2034-01-05
AI Technical Summary
The optical device test device cannot be used normally without an external power supply because the 5.0v voltage output by the computer does not match the 3.3v required by the test device, which can easily lead to damage to the test device.
An optical device testing device including a PCB board, a test module, an external power supply module, a test power supply module and a power supply mode selection module is designed. The 5.0v voltage output by the test computer is reduced to 3.3v through the step-down circuit, and the current reverse flow is prevented through the clamp circuit to ensure that the test module can work normally under different power supply conditions.
The adaptability of the test device under different power supply conditions is achieved, damage caused by voltage mismatch is avoided, and the stability and reliability of the test device are ensured.
Smart Images
Figure CN222394115U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of optical devices, and in particular to a testing device for optical devices. Background Art
[0002] The optical device test device is mainly used to test the performance of the optical device. The optical device test device needs to be connected to a 3.3v power supply during operation. During use, an external 3.3v power supply is provided to the optical device test device.
[0003] However, in actual test scenarios, there is often no external power supply, and at this time, the test computer is required to provide power to the test device of the optical device. However, the voltage output on the computer is 5.0v, which is inconsistent with the 3.3v required by the test device. Therefore, when using the computer to power the test device, it is easy to cause damage to the test device or make it unable to work properly. Summary of the invention
[0004] The content of this application is used to introduce concepts in a brief form, which will be described in detail in the detailed implementation section below. The content of this application is not intended to identify the key features or essential features of the technical solution claimed for protection, nor is it intended to limit the scope of the technical solution claimed for protection.
[0005] In order to solve the technical problem that the existing testing device has a relatively high requirement for power supply, some embodiments of the present application provide a testing device for an optical device, including a PCB board;
[0006] A test module is provided on the PCB board and is used to test the optical device;
[0007] The external power supply module is arranged on the PCB board and is used to connect to a 3.3v external power supply;
[0008] The test power supply module is arranged on the PCB board and is used to connect to the test computer to access a 5V power supply;
[0009] A power supply mode selection module is arranged on the PCB board and is connected to the external power supply module and the test power supply module respectively. The power supply mode selection module is used to select any one of the external power supply module and the test power supply module for power supply to the test module;
[0010] Wherein, the test power supply module comprises: a computer interface and a step-down circuit connected to the computer interface, and the step-down circuit is connected to the power supply mode selection module.
[0011] In the solution provided by the present application, when the external power supply module is connected to a 3.3v external power supply, the power supply mode selection module can select a 3.3v external power supply to supply power to the test module. When the external power supply module is not connected to a 3.3v external power supply, the power supply mode selection module can select the test power supply module to supply power, and the test power supply module will reduce the voltage of the 5V power supply through a step-down circuit before supplying power, so the test module can be prevented from being damaged due to the connection to an excessively high voltage, thereby increasing the adaptability of the test device to the power supply and reducing the power supply requirements.
[0012] Furthermore, the step-down circuit includes a MOSFET tube, a voltage comparator, a comparison voltage source, a first resistor and a second resistor; wherein, the source of the MOSFET tube is connected to the computer interface, the gate of the MOSFET tube is connected to the output end of the voltage comparator, the positive pole of the input end of the voltage comparator is connected to the first end of the first resistor, and the second end of the first resistor is connected to the power supply mode selection module; the negative pole of the input end of the voltage comparator is connected to the output end of the comparison voltage source, the input end of the comparison voltage source is connected to the first end of the second resistor, the second end of the second resistor is respectively connected to the first end of the first resistor and the positive pole of the input end of the voltage comparator, and the drain of the MOSFET tube is connected to the second end of the first resistor.
[0013] In the solution provided in the present application, a comparison voltage source and a voltage comparator are provided, which can stably control the voltage near the target voltage, and further control the voltage when the comparison voltage source is 3.3V.
[0014] Furthermore, the step-down circuit also includes a first capacitor and a second capacitor, the first end of the first capacitor is connected to the source level of the MOSFET tube, the second end of the first capacitor is grounded and connected to the input end of the comparison voltage source, the first end of the second resistor and the second end of the second capacitor, and the first end of the second capacitor is connected to the power supply mode selection module.
[0015] In this solution, the current can be filtered by setting the first capacitor and the second capacitor to ensure that the power supply with stable current and voltage of 3.3V can be output.
[0016] Furthermore, the test power supply module also includes a first filter circuit, which is arranged between the computer interface and the step-down circuit, and the current output by the computer interface is input to the step-down module.
[0017] In this solution, the current can be filtered by the first filtering circuit to ensure the stability of the output current.
[0018] Furthermore, the power supply mode selection module includes a selection switch, a protection circuit connected to the selection switch, and a second filtering circuit connected to the protection circuit. The selection switch is a single-pole double-throw switch, and the two static contacts of the selection switch are respectively connected to the external power supply module and the test power supply module.
[0019] In the technical solution provided by the present application, a single-pole double-throw switch is provided to realize the switching of different power supply modules. The second filtering circuit can filter the power supply connected to the external power supply module and the test power supply module.
[0020] As a second aspect of the present application, when the test power supply module is connected to the test computer and connected to a 5V power supply, the test computer also needs to be connected to the test module to control the test module to test the optical device and collect the test results. However, during the test, the test module is likely to generate a large current that flows back into the test computer through the computer interface, thereby damaging the test computer.
[0021] Furthermore, the test module is connected to the computer interface, and a clamping circuit is provided between the test module and the computer interface.
[0022] In the technical solution provided in the present application, a clamping circuit is provided between the test module and the computer interface, and the current is stabilized by the clamping circuit, thereby preventing the current from flowing back into the test computer.
[0023] Further, the clamping circuit includes a first diode, a second diode, a third diode, a fourth diode and a fifth diode;
[0024] The first diode and the second diode are connected in series to form a first branch, and the third diode and the fourth diode are connected in series to form a second branch; the first branch and the second branch are connected in parallel; the first branch, the second branch, and the fifth diode are connected in parallel.
[0025] In this solution, it is possible to prevent large current from flowing back into the operating computer through the USB cable, thus protecting the normal use of the computer. At the same time, due to its voltage stabilization function, it can always maintain a stable voltage within a specific voltage range, and even after a certain current change, the voltage can still be maintained within a stable range. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The illustrative embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application.
[0027] In addition, throughout the drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and that the components and elements are not necessarily drawn to scale.
[0028] In the attached picture:
[0029] Figure 1 It is a structural schematic diagram of a testing device for optical devices;
[0030] Figure 2 is a schematic diagram of a step-down circuit;
[0031] Figure 3 is a schematic diagram of the clamping circuit;
[0032] Figure 4 Schematic diagram of the structure of the testing device for optical devices in Example 2.
[0033] Reference numerals:
[0034] 1. MOSFET tube; 2. Voltage comparator; 3. Comparison voltage source; 4. First resistor; 5. Second resistor;
[0035] 1a, first diode; 2a, second diode; 3a, third diode; 4a, fourth diode; 5a, fifth diode; 6a, first output line; 7a, second output line; DETAILED DESCRIPTION
[0036] 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 set forth herein. On the contrary, 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.
[0037] It should also be noted that, for ease of description, only the parts related to the invention are shown in the drawings. In the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other.
[0038] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments.
[0039] Embodiment 1:
[0040] Reference Figure 1 The optical device test device includes a PCB board, a test module, an external power supply module, a test power supply module, and a power supply selection module. The PCB board is the main body of the test device, and the test module, the external power supply module, the test power supply module, and the power supply selection module are all arranged on the PCB board. The test module, the external power supply module, the test power supply module, and the power supply selection module are electronic components integrated on the PCB board.
[0041] The test module is used to test the optical device. The optical device to be tested is installed on the test module, and the test module can test the performance of the optical device to be tested. When the test module is working, it is necessary to provide power to the test module. The power supply can be a prepared standard power supply, that is, a 3.3v power supply. It can also be directly obtained from the USB interface of the test computer.
[0042] To this end, the aforementioned external power supply module, test power supply module and power supply mode selection module are arranged on the PCB board. The power supply mode selection module is connected to the external power supply module and the test power supply module respectively. The external power supply module is an interface of the external power supply. After the external power supply is connected to the external power supply module, the current output by the external power supply is input to the test module through the power supply selection module to supply power to the test module. At the same time, the test power supply module is an interface of the test computer. After the test power supply module is connected to the UCB interface of the test computer, the current output by the test computer is input to the test module through the power supply selection module to supply power to the test module.
[0043] During use, the test items of the test module and the data obtained after the test are associated with the test computer. Therefore, the test computer and the test module need to be connected when working. In this solution, in the absence of an external power supply, the power supply module selection module allows the test computer to assume part of the power supply function. When selecting an external power supply, the USB interface of the test computer still needs to be connected to the test power supply module so that the test computer and the test module can be connected.
[0044] In this embodiment, the power supply mode selection module includes a selection switch, a protection circuit connected to the selection switch, and a second filter circuit connected to the protection circuit. The selection switch is a single-pole double-throw switch, and the two static contacts of the selection switch are respectively connected to the external power supply module and the test power supply module. The selection switch can be a relay or a manually controlled switch. In this way, when different power supplies are connected, the correct line can be selected to allow the current of the power supply to flow into the test module. The protection circuit can be a self-recovering protection wire, which will automatically disconnect when the current is too large.
[0045] Furthermore, the general working voltage of the test module is 3.3v, but the voltage output by the USB interface of the test computer is 5.0v. Therefore, in order to avoid the test module being damaged or unable to be used normally due to excessive current when the test computer is used as a power source.
[0046] Furthermore, the test power supply module includes: a computer interface and a step-down circuit connected to the computer interface, wherein the step-down circuit is connected to the power supply mode selection module. The test power supply module also includes a first filter circuit, which is arranged between the computer interface and the step-down circuit, and the current output by the computer interface is input to the step-down module.
[0047] The first filter circuit is a common filter circuit, and its specific structure will not be described here.
[0048] like Figure 2 As shown: the step-down circuit is used to reduce the 5.0v voltage output by the computer interface to 3.3v. In fact, the computer interface described in this scheme is actually a USB interface. In this way, it can be connected to the USB interface of the test computer.
[0049] Specifically, the step-down circuit includes a MOSFET tube 1, a voltage comparator 2, a comparison voltage source 3, a first resistor 4 and a second resistor 5; wherein the source of the MOSFET tube 1 is connected to the computer interface, the gate of the MOSFET tube 1 is connected to the output end of the voltage comparator 2, the positive electrode of the input end of the voltage comparator 2 is connected to the first end of the first resistor 4, and the second end of the first resistor 4 is connected to the power supply mode selection module; the negative electrode of the input end of the voltage comparator 2 is connected to the output end of the comparison voltage source 3, the input end of the comparison voltage source 3 is connected to the first end of the second resistor 5, the second end of the second resistor 5 is respectively connected to the first end of the first resistor 4 and the positive electrode of the input end of the voltage comparator 2, and the drain of the MOSFET tube 1 is connected to the second end of the first resistor 4. The MOSFET tube 1 is a P-MOS tube. The voltage comparison source is a functional module on the test device that can generate a stable 3.3v voltage. The functional module can be provided by the internal reference source of the chip or connected through an external circuit. The voltage comparator 2 is a common voltage comparator 2 on the market, which is used to compare the voltages of the two input ends. The specific function refers to the principle explanation of the step-down circuit.
[0050] The principle of the step-down circuit is:
[0051] The input signal (the signal output by the USB interface) is given to the negative electrode of the input terminal of the voltage comparator. When the output signal decreases, the potential at both ends of the voltage divider circuit composed of two resistors decreases accordingly, and then the voltage at the positive input terminal of the voltage comparator decreases. By comparing it with the reference voltage at the negative output terminal, its output decreases, so the voltage applied to the gate of the MOSFET tube decreases, while the input signal remains unchanged, that is, |V GSThe value of | will increase, and the current flowing through the source and drain will increase, making the output signal (the signal output by the drain of the MOSFET tube) stable near the expected output value. Similarly, when the output signal increases, the potential across the first resistor and the second resistor increases, the gate voltage of the MOSFET tube increases, and the corresponding output increases, and the voltage to the gate of the MOSFET tube increases, while the input signal remains unchanged, that is, |V GS The value of | will decrease, and the current flowing through the source and drain will decrease, making the output signal stable near the expected output value.
[0052] refer to Figure 4 Embodiment 2: Embodiment 2 is based on Embodiment 1, and a clamping circuit is provided to prevent the current of the test module from flowing back into the test computer when the test module is working. The test module includes a first filter circuit, a clamping circuit and a test circuit. The optical device to be tested is installed on the test circuit to complete the test work. The specific structure of the test circuit is not described here. The first filter circuit and the second filter circuit are common filter circuits in the field, and the specific circuit structure is not described here.
[0053] refer to Figure 3 Specifically: the test module is connected to the computer interface, and a clamping circuit is provided between the test module and the computer interface, and the clamping circuit includes a first diode 1a, a second diode 2a, a third diode 3a, a fourth diode 4a and a fifth diode 5a;
[0054] The first diode 1a and the second diode 2a are connected in series to form a first branch, and the third diode 3a and the fourth diode 4a are connected in series to form a second branch; the first branch and the second branch are connected in parallel; the first branch, the second branch, and the fifth diode 5a are connected in parallel, the first end of the fifth diode 5a is grounded, and the second end is connected to the USB interface.
[0055] A first end of a first connecting line is connected between the first diode 1a and the second diode 2a, and a second end of the second connecting line is connected to the middle position of the first output line 6a, and the first and second ends of the first output line 6a form a positive input end and a positive output end of the USB differential signal of the clamping circuit; a first end of a second connecting line is connected between the third diode 3a and the fourth diode 4a, and a second end of the second connecting line is connected to the middle position of the second output line, and the first and second ends of the second output line 7a form a negative output end of the USB differential signal of the clamping circuit.
[0056] In the technical solution provided in the present application, there are three input terminals and two output terminals in the clamping circuit. The three input terminals are respectively the positive input terminal of the USB differential signal of the first output line, the positive input terminal of the USB differential signal of the second output line, and the second end of the fifth diode.
[0057] Correspondingly, the two input and output terminals are respectively the negative output terminal of the USB differential signal of the first output line and the negative output terminal of the USB differential signal of the second output line. In fact, these ports are all hidden in the part connecting the USB interface and the clamping circuit.
[0058] refer to Figure 3 As shown, according to the unidirectional conductivity of the diode, the input voltage signal is clamped between 5V+0.7 and GND-0.7. The circuit analysis is as follows: Assume that the conduction voltage of the diode is 0.7V.
[0059] (1) Taking the USB differential signal + as an example, when the input signal is greater than 5V+0.7V, the upper right diode is turned on and the left diode is turned off. Even if the voltage at the input end continues to increase, the output signal is always stabilized near 5V+0.7V, thereby avoiding damage to the subsequent circuit due to sudden changes in current and voltage.
[0060] (2) Taking the USB differential signal - as an example, when the input signal is less than GND-0.7V, the left diode below is turned on and the right diode is turned off. At this time, the voltage of the output port will be clamped at GND-0.7V, and the output will not change no matter how small the input is.
[0061] like Figure 3 As shown in the figure, a voltage regulator diode is connected in parallel in the clamping circuit. The 5V voltage of the test module comes from the USB interface on the computer side and is transferred out through a filter circuit. According to the characteristics of the voltage regulator diode, when the reverse voltage is less than the stable voltage, its function is as that of a common diode, with a very small forward current and a large reverse current; but when the reverse voltage is greater than its voltage regulation limit, it will immediately switch to a voltage regulation state, reducing the reverse current, thereby preventing a large current from flowing back into the operating computer through the connecting wire, protecting the computer from normal use. At the same time, due to its voltage regulation function, it can always keep the voltage stable within a specific voltage range, and even after a certain current change, the voltage can still be kept within a stable range.
[0062] The above description is only some preferred embodiments of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present application is not limited to the technical solutions formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above invention concept. For example, the above features are replaced with (but not limited to) the technical features with similar functions disclosed in the embodiments of the present application to form a technical solution.
Claims
1. A testing device for an optical device, characterized in that: include: PCB board; A test module is provided on the PCB board and is used to test the optical device; The external power supply module is arranged on the PCB board and is used to connect to a 3.3v external power supply; The test power supply module is arranged on the PCB board and is used to connect to the test computer to access a 5V power supply; A power supply mode selection module is arranged on the PCB board and is connected to the external power supply module and the test power supply module respectively. The power supply mode selection module is used to select any one of the external power supply module and the test power supply module for power supply to the test module; Wherein, the test power supply module comprises: a computer interface and a step-down circuit connected to the computer interface, and the step-down circuit is connected to the power supply mode selection module.
2. The optical device testing device according to claim 1, characterized in that: The step-down circuit includes a MOSFET tube, a voltage comparator, a comparison voltage source, a first resistor and a second resistor; wherein the source of the MOSFET tube is connected to a computer interface, the gate of the MOSFET tube is connected to the output end of the voltage comparator, the positive electrode of the input end of the voltage comparator is connected to the first end of the first resistor, and the second end of the first resistor is connected to a power supply mode selection module; the negative electrode of the input end of the voltage comparator is connected to the output end of the comparison voltage source, the input end of the comparison voltage source is connected to the first end of the second resistor, the second end of the second resistor is respectively connected to the first end of the first resistor and the positive electrode of the input end of the voltage comparator, and the drain of the MOSFET tube is connected to the second end of the first resistor.
3. The optical device testing device according to claim 2, characterized in that: The step-down circuit also includes a first capacitor and a second capacitor, wherein the first end of the first capacitor is connected to the source level of the MOSFET tube, the second end of the first capacitor is grounded and connected to the input end of the comparison voltage source, the first end of the second resistor and the second end of the second capacitor, and the first end of the second capacitor is connected to the power supply mode selection module.
4. The optical device testing device according to claim 3, characterized in that: The test power supply module also includes a first filter circuit, which is arranged between the computer interface and the step-down circuit. The current output by the computer interface is input to the step-down module.
5. The optical device testing device according to claim 3, characterized in that: The power supply mode selection module includes a selection switch, a protection circuit connected to the selection switch, and a second filter circuit connected to the protection circuit. The selection switch is a single-pole double-throw switch, and the two static contacts of the selection switch are respectively connected to the external power supply module and the test power supply module.
6. The optical device testing device according to claim 2, characterized in that: The test module is connected to the computer interface, and a clamping circuit is arranged between the test module and the computer interface.
7. The optical device testing device according to claim 6, characterized in that: The clamping circuit includes a first diode, a second diode, a third diode, a fourth diode and a fifth diode; The first diode and the second diode are connected in series to form a first branch, and the third diode and the fourth diode are connected in series to form a second branch; the first branch and the second branch are connected in parallel; the first branch, the second branch, and the fifth diode are connected in parallel.