Method and device for testing LED or LD constant current source

Abstract

The invention provides an LED or LD constant current source testing method and device, and belongs to the field of instrument testing. The performance testing process comprises the steps of testing current value setting, load resistance switching, voltage obtaining, data processing and current waveform displaying. The function test comprises a current protection function test, a temperature protection function test, a current protection function test, an analog voltage modulation test and a PWM modulation function test. By switching load resistance, acquiring sampling voltage and processing data, a curve graph of output current is obtained, and a test report is automatically formed. And the current-limiting protection function of the constant-current driving power supply is verified by increasing the current. The temperature protection function of the constant-current driving voltage is verified by controlling the heat dissipation device; through current detection, a current modulation function and a control mode function are verified. The test method is high in test precision, comprehensive in test items and high in speed, and the detection efficiency is greatly improved.

Description

Technical Field

[0001] The invention relates to the field of instrument testing, and in particular to a method and a device for testing an LED or LD constant current source. Background Art

[0002] At present, with the development of electronic technology, the application of constant current source is becoming more and more extensive, especially in medical cold light source and medical imaging system, which generally adopts one or more high-power LED or LD, and has high requirements on the stability of output light. This puts forward higher requirements on the performance detection of constant current source, which not only requires efficient and comprehensive detection of various indicators of constant current source, but also requires the consistency and authenticity of detection environment and detection conditions. At present, most detection devices adopt the probe method. Although it can detect the output current indicator, it also has its limitations. For example, if the circuit board is adjusted, then this set of test device may not be used, and the test record can only be completed manually. This test method and test device are not only inefficient, but also not comprehensive enough. Summary of the invention

[0003] The technical problems to be solved by the present invention are low detection efficiency, single detection item, instability of detection environment and detection conditions, etc. of LED or LD constant current source test.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is to provide a method for testing a constant current source of an LED or LD. The specific solution is as follows:

[0005] A method for testing an LED or LD constant current source comprises the following steps:

[0006] S1. Set the working current value of the component under test, and read the preset value in the memory at the same time to obtain the upper limit value of the current, the upper limit value of the temperature and the current error range;

[0007] S2, temperature protection function test: turn off the heat sink on the load resistor, and obtain the temperature and current values ​​of the load resistor in real time. When the current temperature value of the load resistor is greater than the preset temperature upper limit, the current protection function of the constant current drive power supply should be turned on, that is, the current value of the load resistor is zero;

[0008] S3, current protection function test: increase the analog voltage is the input voltage value, and obtain the current current value in real time through the waveform sampling board. When the analog voltage value is equal to the upper limit value of the analog voltage, the current protection function should be activated, that is, the current current value is zero;

[0009] S4, analog voltage modulation test: change the analog voltage value, and detect whether the current current value changes accordingly with the change of the analog voltage value;

[0010] S5, PWM modulation function test: change the PWM duty cycle, obtain the current current value in real time, and upload the current test data to the control system; if the current current value changes accordingly with the change of the duty cycle, the touch screen displays "PWM modulation current is normal", and jumps to S6; otherwise jumps to S7;

[0011] S6, current stability test: switch different load resistances, obtain the current current value through the waveform sampling board, calculate the error of the current current value, and then compare it with the preset current error range to confirm whether the current current is stable;

[0012] S7. After the test, the touch screen displays "Constant current drive power supply is abnormal!";

[0013] S8. The control system generates an electronic test report based on the uploaded test data;

[0014] S9. Complete function and performance testing and the test ends.

[0015] Furthermore, the temperature protection function test of step S2 includes the following steps:

[0016] S21, turning off the heat dissipation device on the load resistor, and acquiring the current temperature and current current on the load resistor in real time;

[0017] S22, when the current temperature value is greater than the upper temperature limit, jump to process S21;

[0018] S23, when the current temperature value is less than the upper temperature limit, if the current current value is zero, it means that the temperature protection function of the tested component is turned on; upload the current test data to the control system, and the touch screen displays "temperature protection is normal", and jump to process S25;

[0019] S24, when the current temperature value is less than the upper temperature limit, if the current current value is not zero, it means that the temperature protection function of the tested component is not turned on; upload the current test data to the control system and jump to S7;

[0020] S25, start the heat dissipation device on the load resistor to put the constant current drive power supply in normal working state.

[0021] Furthermore, the current protection function test of S3 includes the following steps:

[0022] S31, obtaining the current current value, and confirming that the constant current driving power supply is in normal working state;

[0023] S32, increase the analog input voltage to the analog voltage upper limit value, and obtain the current current value of the load resistance;

[0024] S33, if the current value is zero, it means that the current protection function of the tested part is turned on; upload the test data to the control system, and the touch screen displays "current protection is normal", and jump to S4;

[0025] S34. If the current value is not zero, it means that the current protection function of the tested component is not turned on; upload the current test data to the control system and jump to S7.

[0026] Furthermore, the analog voltage modulation test of S4 includes the following steps:

[0027] S41, obtaining the current current value, and confirming that the constant current driving power supply is in a normal working state;

[0028] S42, the analog voltage value increases first and then decreases, and the current current value is detected at the same time, and the current test data is uploaded to the control system; if the change of the current current value is also first increased and then decreased, the touch screen displays "analog voltage modulation is normal" and jumps to S5; otherwise, jumps to S7.

[0029] Furthermore, the current stability test in step S6 includes the following steps:

[0030] S61, switch to the load resistance of the required gear, and turn on the constant current drive power supply;

[0031] S62, according to the obtained adopted voltage, calculate the current current value and the current error range, upload the test data to the control system, and display the current waveform in real time on the touch screen;

[0032] S63. If the current load resistance level is the tenth level, jump to S8; otherwise, return to S6.

[0033] The present invention also provides a test device for an LED or LD constant current source, characterized in that it comprises a control system, a waveform sampling board system, a load module, a temperature feedback module, a display feedback module, a heat dissipation controller, a heat dissipation actuator, and a report output module; the waveform sampling board system and the load module are respectively connected to the control system for communication and test data transmission; the display module and the report output module are respectively connected to the control system for displaying and exporting information; the heat dissipation controller and the temperature feedback module are respectively connected to the load module for temperature testing and control; the tested components are respectively connected to the waveform sampling system and the load module; the heat dissipation actuator is connected to the heat dissipation controller;

[0034] The control system is an embedded control system. The waveform sampling system includes a microprocessor, a precision A / D converter, a precision power supply and a communication module. The waveform sampling system provides the tested component with the analog voltage signal and PWM control signal required for the test, and converts the collected analog signal through A / D conversion. The microprocessor processes the converted analog signal and uploads the test data and processing results to the control system. The load module includes a microprocessor, a load resistor, a relay, a sampling amplifier circuit and an A / D converter. The temperature feedback module includes at least two temperature sensors. The display module is a touch screen. The heat dissipation controller adjusts the speed of the fan according to the feedback temperature data. The heat dissipation actuator includes a fan and a heat sink. The report output module is connected to a printer and a U disk.

[0035] Furthermore, the control system is a PC, and the display module is a display.

[0036] Furthermore, the temperature sensor is a thermistor or an IC temperature sensor.

[0037] The beneficial effects of the present invention are: the control system controls and coordinates the waveform sampling system, the load module, the display module and the report output module, so that the entire test and output process is completed automatically, which greatly improves the accuracy and efficiency of the detection; by using the load module instead of the LED or LD, the phenomenon that the load index changes or drifts due to long-term testing is avoided, so that the consistency and stability of the test environment are guaranteed; the load module is switched at each test current value, which fully simulates the phenomenon that the internal resistance of the actual load changes during operation, and truly tests the output current stability. The LED or LD constant current source test method and device provided by the present invention not only realizes the performance test of current stability, but also realizes various functional tests such as temperature protection, current protection, analog voltage modulation and PWM modulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A flow chart of a LED or LD constant current source testing method provided by an embodiment of the present invention;

[0039] Figure 2 A schematic structural diagram of a LED or LD constant current source testing device provided in an embodiment of the present invention.

[0040] Description of labels:

[0041] 1. Control system; 2. Waveform sampling system; 3. Load module; 4. Temperature feedback module; 5. Display module; 6. Heat dissipation controller; 7. Heat dissipation actuator; 8. Report output module; 9. Component under test. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0044] In order to keep the following description of the embodiments of the present invention clear and concise, the present invention omits detailed descriptions of some known functions and known components.

[0045] Please refer to the figure, the first embodiment of the present invention is:

[0046] Attached Figure 2 The control system 1 adopts an embedded system, and the functions of printing, load module control, waveform sampling module control, test data reception, touch screen display, test report storage, etc. are all completed by the embedded system; the waveform sampling system 2 provides the analog voltage signal and PWM signal required for the test to the tested component 9, converts the acquired sampling voltage into a digital voltage through a precision A / D converter, calculates the current real-time current, and uploads the test data and processing results to the control system 1; the load module 3 switches the corresponding load resistance according to the received command of the control system 1, and obtains the temperature of the load resistance in real time, and uploads the processed data to the control system 1; the temperature feedback module 4 is composed of multiple temperature sensors; the display module 5 is a touch screen; the heat dissipation controller 6 adjusts the speed of the fan according to the feedback temperature data; the heat dissipation actuator 7 is composed of a fan and a radiator; the report output module 8 can be connected to a printer and a U disk, and the test report can be printed out by the printer or copied to a U disk.

[0047] From sending the start test instruction to generating the test report, the whole process is completed automatically. The steps of the control process and method include:

[0048] Step S1: Determine the preset value, the memory is used to store the upper limit of current, the upper limit of temperature, the current error range, the upper limit of analog voltage, the frequency and duty cycle of PWM, etc. These parameters are mainly used to determine whether the performance index is qualified and whether the function is abnormal.

[0049] Step S2: Temperature protection detection, the control system, load module, heat dissipation controller, heat dissipation actuator and temperature feedback module jointly complete the temperature protection detection. The load module receives the temperature protection detection instruction, sends an instruction to the heat dissipation controller, turns off the heat dissipation actuator, and the temperature on the load resistor rises rapidly. When it is detected that the current temperature reaches the upper limit temperature value, it detects whether the current of the measured component is zero. If the current current is zero, it means that the temperature protection function of the measured component is normal, and jumps to S3; if the current current is not zero, it means that the temperature protection function of the measured component is abnormal, and jumps to S7.

[0050] The temperature sensor can use a thermistor. When the temperature changes, the corresponding resistance value will change accordingly. The resistance value of the thermistor is obtained by the A / D converter to obtain the voltage value and then converted to the resistance value. According to the resistance value, it is converted to the corresponding temperature value. The conversion formula used is:

[0051] Rt=R*EXP(B*(1 / T1-1 / T2))

[0052] Where T1 and T2 refer to Kelvin temperature, that is, T2 = 273.15 + 25. Rt is the resistance of the thermistor at temperature T1; R is the nominal resistance of the thermistor at room temperature T2; B is an important parameter of the thermistor, and its value is 3380.

[0053] Step S3: Current protection test. Under the premise of ensuring the normal operation of the tested component, the waveform sampling module obtains the current sampling voltage from the load module, calculates the current value of the tested component, and then provides the maximum analog voltage to the tested component. At the same time, it calculates the current current of the tested component and confirms whether the current current is zero. If the current current is zero, it means that the current protection function of the tested component is normal, and jumps to S4; if the current current is not zero, it means that the current protection function of the tested component is abnormal, and jumps to S7.

[0054] Step S4: Analog voltage modulation test. Under the premise of ensuring the normal operation of the tested component, the waveform sampling module calculates the current value of the tested component, and then increases the analog voltage provided to the tested component by 20% and then decreases by 20%. At the same time, the current current of the tested component is calculated to confirm whether the current current increases first and then decreases. If this is the change trend, it means that the analog voltage adjustment function of the tested component is normal, and jump to S5; if not, it means that the analog voltage modulation function of the tested component is abnormal, and jump to S7.

[0055] Step S5: PWM modulation test. Under the premise of ensuring the normal operation of the tested component, the waveform sampling module calculates the current value of the tested component, and then provides a PWM signal with a duty cycle of 50% to the tested component, and at the same time calculates the current current of the tested component to confirm whether the current current is decreasing. If the current current is decreasing, it means that the PWM modulation function of the tested component is normal, and jump to S6; if not, it means that the PWM modulation function of the tested component is abnormal, and jump to S7.

[0056] Step S6: Current stability test. The current stability test selects 3 current levels for testing, namely 10% of the maximum current, 50% of the maximum current and the maximum current. By switching the load resistance of 10 levels respectively, it simulates the actual use of the tested component. When the internal resistance of the connected load changes, the output current of the tested component is also constant and stable.

[0057] The control system sends the instruction of current stability test to the load module and waveform sampling module. The waveform sampling module provides an analog voltage signal to the tested component, so that the current of the tested component is 10% of the maximum current. The load module switches to the specified load resistance through the relay. After starting the tested component, the current current value is obtained, the test data is uploaded, and then the tested component is turned off, the load resistance gear is switched, and the current current value and the test data are obtained again until the measurement of 10 gears is completed. The control system processes the data according to the uploaded test data and displays the current waveform on the touch screen in real time. If the tested current value is within the current error range, it means that the current output of the tested component is normal, otherwise the current output is unstable.

[0058] According to the above process, after changing the current of the tested component, test it again until the test of the three current levels is completed and jump to S8.

[0059] Step S7: After the test is completed, the touch screen displays "Constant current drive power supply abnormality!".

[0060] Step S8: The control system generates an electronic test report based on the uploaded test data, which can also be printed out by a printer.

[0061] Step S9: Complete the function and performance test and the test ends.

[0062] In summary, the control system controls and coordinates the waveform sampling system, load module, display module and report output module, so that the entire test and output process is completed automatically, which greatly improves the accuracy and efficiency of the detection; by using the load module instead of the LED or LD, the phenomenon that the load index changes or drifts due to long-term testing is avoided, so that the consistency and stability of the test environment are guaranteed; the load module is switched at each test current value, which fully simulates the phenomenon that the internal resistance of the actual load changes during operation, and truly tests the output current stability. The LED or LD constant current source test method and device provided by the present invention not only realizes the performance test of current stability, but also realizes various functional tests such as temperature protection, current protection, analog voltage modulation and PWM modulation.

[0063] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for testing a LED or LD constant current source, characterized in that: The following steps are involved: S1. Set the working current value of the component under test, and read the preset value in the memory at the same time to obtain the upper limit value of the current, the upper limit value of the temperature and the current error range; S2, temperature protection function test: turn off the heat sink on the load resistor, and obtain the temperature and current values ​​of the load resistor in real time. When the current temperature value of the load resistor is greater than the preset temperature upper limit, the current protection function of the constant current drive power supply should be turned on, that is, the current value of the load resistor is zero; S3, current protection function test: increase the analog voltage is the input voltage value, and obtain the current current value in real time through the waveform sampling board. When the analog voltage value is equal to the upper limit value of the analog voltage, the current protection function should be activated, that is, the current current value is zero; S4, analog voltage modulation test: change the analog voltage value, and detect whether the current current value changes accordingly with the change of the analog voltage value; S5, PWM modulation function test: change the PWM duty cycle, obtain the current current value in real time, and upload the current test data to the control system; If the current value changes accordingly with the duty cycle, the touch screen displays "PWM modulation current is normal" and jumps to S6; otherwise, jumps to S7; S6, current stability test: switch different load resistances, obtain the current current value through the waveform sampling board, calculate the error of the current current value, and then compare it with the preset current error range to confirm whether the current current is stable; S7. After the test, the touch screen displays "Constant current drive power supply is abnormal!"; S8. The control system generates an electronic test report based on the uploaded test data; S9. Complete function and performance testing and the test ends.

2. The method for testing a LED or LD constant current source according to claim 1, characterized in that: The temperature protection function test of step S2 comprises the following steps: S21, turning off the heat dissipation device on the load resistor, and acquiring the current temperature and current current on the load resistor in real time; S22, when the current temperature value is greater than the upper temperature limit, jump to process S21; S23, when the current temperature value is less than the upper temperature limit, if the current current value is zero, it means that the temperature protection function of the tested component is turned on; upload the current test data to the control system, and the touch screen displays "temperature protection is normal", and jump to process S25; S24, when the current temperature value is less than the upper temperature limit, if the current current value is not zero, it means that the temperature protection function of the tested component is not turned on; upload the current test data to the control system and jump to S7; S25, start the heat dissipation device on the load resistor to put the constant current drive power supply in normal working state.

3. The method for testing a LED or LD constant current source according to claim 1, characterized in that: The current protection function test of S3 includes the following steps: S31, obtaining the current current value, and confirming that the constant current driving power supply is in normal working state; S32, increase the analog input voltage to the analog voltage upper limit value, and obtain the current current value of the load resistance; S33, if the current value is zero, it means that the current protection function of the tested part is turned on; upload the test data to the control system, and the touch screen displays "current protection normal", and jump to S4; S34. If the current value is not zero, it means that the current protection function of the tested component is not turned on; upload the current test data to the control system and jump to S7.

4. The method for testing a LED or LD constant current source according to claim 1, characterized in that: The S4 analog voltage modulation test includes the following steps: S41, obtaining the current value and confirming that the constant current driving power supply is in normal working state; S42, the analog voltage value increases first and then decreases, and the current current value is detected at the same time, and the current test data is uploaded to the control system; if the change of the current current value is also first increased and then decreased, the touch screen displays "analog voltage modulation is normal" and jumps to S5; otherwise, jumps to S7.

5. The method for testing a LED or LD constant current source according to claim 1, characterized in that: The current stability test of step S6 includes the following steps: S61, switch to the load resistance of the required gear, and turn on the constant current drive power supply; S62, according to the obtained adopted voltage, calculate the current current value and the current error range, upload the test data to the control system, and display the current waveform in real time on the touch screen; S63. If the current load resistance level is the tenth level, jump to S8; otherwise, return to S6.

6. A test device for LED or LD constant current source, characterized in that: It includes a control system, a waveform sampling board system, a load module, a temperature feedback module, a display feedback module, a heat dissipation controller, a heat dissipation actuator, and a report output module; the waveform sampling board system and the load module are respectively connected to the control system for communication and test data transmission; the display module and the report output module are respectively connected to the control system for displaying and exporting information; The heat dissipation controller and the temperature feedback module are respectively connected to the load module for temperature testing and control; the tested component is respectively connected to the waveform sampling system and the load module; the heat dissipation actuator is connected to the heat dissipation controller; The control system is an embedded control system. The waveform sampling system includes a microprocessor, a precision A / D converter, a precision power supply and a communication module. The waveform sampling system provides the tested component with the analog voltage signal and PWM control signal required for the test, and converts the collected analog signal through A / D conversion. The microprocessor processes the converted analog signal and uploads the test data and processing results to the control system. The load module includes a microprocessor, a load resistor, a relay, a sampling amplifier circuit and an A / D converter. The temperature feedback module includes at least two temperature sensors. The display module is a touch screen. The heat dissipation controller adjusts the speed of the fan according to the feedback temperature data. The heat dissipation actuator includes a fan and a heat sink. The report output module is connected to a printer and a U disk.

7. A testing device for a LED or LD constant current source according to claim 6, characterized in that: The control system is a PC, and the display module is a display.

8. A testing device for a LED or LD constant current source according to claim 6, characterized in that: The temperature sensor is a thermistor or an IC temperature sensor.

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