CN112904221A - Improved load unit for testing LED backlight driving power supply and intelligent load device - Google Patents
Improved load unit for testing LED backlight driving power supply and intelligent load device Download PDFInfo
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- CN112904221A CN112904221A CN202110329717.0A CN202110329717A CN112904221A CN 112904221 A CN112904221 A CN 112904221A CN 202110329717 A CN202110329717 A CN 202110329717A CN 112904221 A CN112904221 A CN 112904221A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/40—Testing power supplies
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/28—Provision in measuring instruments for reference values, e.g. standard voltage, standard waveform
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Abstract
An improved load unit and intelligent load device for testing an LED backlight driving power supply, the intelligent load device comprising: n rectifier diodes with positive and negative electrodes connected in series in sequence, wherein the forward conduction voltage of any adjacent m rectifier diodes on the series connection sequence is equal to the forward conduction voltage of a single LED, and n is an integral multiple of m; the i relays are used for switching the rectifier diodes in a segmented manner, the rectifier diodes which are divided into one segment are a load unit, and the number of the rectifier diodes of the i load units is an integral multiple of m; the central control unit is used for respectively and independently controlling the on-off state of each relay; and a voltage acquisition unit and a current acquisition unit. The invention replaces the LED with the rectifier diode, has low price, strong overcurrent resistance and long service life and can not cause light pollution; the device has the advantages of lower investment and maintenance cost, environment-friendly equipment without light pollution, and intelligent equipment further improves the production efficiency.
Description
Technical Field
The invention relates to the field of LED backlight driving power supply testing, in particular to an intelligent load device for testing an LED backlight driving power supply of a liquid crystal display.
Background
At present, liquid crystal displays have become important display terminals, and are generally applied to vehicle-mounted instruments, personal computers, televisions, various digital products and various industrial control devices. The lcd screen itself cannot emit light, and a backlight device installed at the back of the lcd screen is required to provide a display capability. Light Emitting diodes, i.e., LEDs (abbreviation of Light Emitting Diode), have the advantages of high luminance, fast response speed, energy saving, long service life, etc., and are becoming the preferred Light source. However, the operating condition of the LED cannot be directly connected to the commercial power, and a special driving circuit is needed to provide power to adjust the brightness and display effect of the screen, and this special driving circuit is called as the LED backlight driving power.
The LED backlight driving power source, which is an important component of the liquid crystal display, must undergo a severe on-load test during the manufacturing process, and thus the load is a major test device. Because the output of the LED backlight driving power supply is not direct-current voltage but output in the form of pulse waves when the LED backlight driving power supply works in a dimming mode, the traditional direct-current electronic load cannot be used for testing; the resistor, which does not have the same volt-ampere characteristics as the LED lamp, cannot be used as a screen test. As a manufacturer for a long time, loads used for testing LED backlight driving power supplies are all formed by actual LED lamp beads.
The load scheme is shown in fig. 1, and comprises a plurality of LEDs (LEDs 1-LEDn) and a plurality of switches (S1-Sn), and the purpose of controlling the number of the LEDs connected in series is achieved by manually calculating and switching the switches S1-Sn, so as to meet the load requirements of the LED backlight driving power supplies with different specifications. The current loading scheme has the following disadvantages:
1. the price of the LED is high, and due to the fact that the types of the liquid crystal displays are numerous, manufacturers need to use LEDs with large numbers to meet the load requirements of LED backlight driving power supplies with various specifications, and the input cost of equipment is high.
2. The LED has weak overcurrent resistance, the tested LED backlight driving power supply often has poor overcurrent, the LED is easily damaged, the LED needs to be frequently replaced, and the equipment maintenance cost is high.
3. The light emitted by the LED is very dazzling and causes light pollution to a production workshop.
4. The LED backlight driving power supplies with different specifications have different output voltages, the number of the LEDs connected in series needs to be calculated manually during testing, then the switches are operated manually for switching, a large amount of manpower and time need to be consumed during large-scale production, and manual operation is easy to cause fatigue and often makes mistakes.
5. The test process cannot be monitored in real time and test results can not be automatically judged, the test data recording function is not available, and quality tracking cannot be carried out.
Disclosure of Invention
The present invention is directed to overcome the above-mentioned deficiencies in the prior art, and to provide an improved load unit and an intelligent load device for testing an LED backlight driving power supply.
The invention adopts a technical scheme for solving the technical problems that:
an improved load cell for testing an LED backlight driving power supply, comprising: the positive pole and the negative pole of the LED are sequentially connected with x rectifier diodes in series, wherein the forward conducting voltage of any adjacent m rectifier diodes on the series connection sequence is equal to the forward conducting voltage of a single LED, and x is an integral multiple of m. And m is 4.
Another technical scheme adopted by the invention for solving the technical problems is as follows:
an intelligent load device for testing an LED backlight driving power supply, comprising:
n rectifier diodes with positive and negative electrodes connected in series in sequence, wherein the forward conduction voltage of any adjacent m rectifier diodes on the series connection sequence is equal to the forward conduction voltage of a single LED, and n is an integral multiple of m;
the i relays are used for switching the rectifier diodes in a segmented manner, the rectifier diodes which are divided into one segment are a load unit, and the number of the rectifier diodes of the i load units is equal to or different integral multiples of m;
the central control unit is used for respectively and independently controlling the on-off state of each relay, the load unit is in short circuit when the central control unit is switched on, and the load unit is switched into a load circuit for testing when the central control unit is switched off;
the voltage acquisition unit sends the working output voltage data of the LED backlight driving power supply to the central control unit during testing;
and the current acquisition unit tests the working output current data of the LED backlight driving power supply and sends the working output current data to the central control unit during testing.
This device still includes: and the operation input unit and the display unit are respectively connected with the central control unit to form an input and output interface for man-machine interaction.
This device still includes: and the communication port is used for the mutual communication between the central control unit and the upper computer.
This device still includes: and the communication address setting switch is connected with the central control unit and can give a unique hardware address code to each device, so that the large-scale networking application of the device is realized.
The voltage acquisition unit includes: the first operational amplifier is used for being connected with two poles of the LED backlight driving power supply, collects the output voltage of the LED backlight driving power supply in real time, and sends the output voltage to the central control unit through the first high-speed AD converter.
The current collection unit includes: and the two poles of the current sampling resistor are connected with a second operational amplifier, the second operational amplifier collects voltage in real time and obtains the current of the load circuit, and the current is transmitted to the central control unit through a second high-speed AD converter.
The central control unit is respectively connected with each relay in a one-to-one correspondence mode through i triodes, the central control unit operates and controls the triodes, and the triodes trigger the on or off of the relays.
The central control unit adopts a 32-bit MCU microprocessor.
Compared with the prior art, the invention has the beneficial effects that:
the invention innovatively uses the rectifier diode to replace the LED for the first time, the rectifier diode not only has the volt-ampere characteristic similar to that of the LED, but also is a more common electronic element, the price is low, the overcurrent resistance is strong, the service life is longer, the LED is not luminous, the LED can not cause light pollution when being applied in large scale, and the LED has no influence on human bodies and environment.
The intelligent load device has the advantages of lower investment and maintenance cost, environment-friendly equipment without light pollution, and intelligent equipment further improves the production efficiency. The switching of the series connection quantity of the rectifier diodes is controlled by the central control unit, the load requirements of LED backlight driving power supplies with different specifications are met, the efficiency is high, and manual operation is not needed. The device has the functions of real-time monitoring, automatic data recording, automatic test result judgment, large-scale networking application and the like, is more intelligently controlled, has high computer operation efficiency, and does not make mistakes.
Drawings
In order to more clearly illustrate the technical solution in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced, wherein:
FIG. 1 is a schematic diagram of a conventional load scheme for testing an LED backlight driving power supply;
FIG. 2 is a schematic diagram of an improved load cell in accordance with a preferred embodiment of the present invention;
fig. 3 is a schematic diagram of the connection of the intelligent load device according to the preferred embodiment of the invention.
Detailed Description
The invention will be further described with reference to the accompanying drawings and specific embodiments. In the preferred embodiments, the terms "upper", "lower", "left", "right", "middle" and "a" are used for clarity of description only, and are not used to limit the scope of the invention, and the relative relationship between the terms and the terms is not changed or modified substantially without changing the technical content of the invention.
Referring to fig. 2 and fig. 3, an intelligent load device for testing an LED backlight driving power supply according to a preferred embodiment of the present invention mainly includes:
n rectifier diodes D1-Dn with positive and negative electrodes connected in series in sequence, wherein the forward conduction voltage of any adjacent m rectifier diodes on the series connection sequence is equal to the forward conduction voltage of a single LED, wherein n is an integral multiple of m; the rectifier diodes connected in series jointly form a load circuit for testing, and are correspondingly connected with the positive electrode and the negative electrode of the LED backlight driving power supply to serve as working loads during testing;
the i relays K1-Ki switch the rectifier diodes D1-Dn in sections by the relays K1-Ki, the rectifier diodes divided into sections are a load unit, i load units are provided, the number of the rectifier diodes of each load unit is integral multiple of m, and the number of the rectifier diodes of different load units can be the same or different;
the central control unit is used for respectively and independently controlling the on-off state of each relay, the load unit is in short circuit when being switched on and does not participate in the test work, and the load unit is switched in a load circuit for test when being switched off and participates in the test work;
the voltage acquisition unit is used for being connected with two poles of the LED backlight driving power supply and sending work output voltage data of the LED backlight driving power supply to the central control unit during testing;
and the current acquisition unit is connected with the load unit in series, the current acquisition unit tests the working output current data of the LED backlight driving power supply and sends the data to the central control unit during testing, and the tested various data are acquired by the central control unit.
This device still includes: the operation input unit and the display unit which are respectively connected with the central control unit form a man-machine interaction interface, set load parameters of the tested LED backlight driving power supply and display test data, wherein the load parameters comprise the serial number of the rectifier diodes, test time parameters, voltage and current data and the like, and can be stored into a test parameter file or imported into the test parameter file and the like, so that the load device is intelligentized and visualized. The operation input unit may be a matrix keyboard or the like, and the display unit may be a display screen or the like.
This device still includes: the upper computer can also carry out load parameter setting, real-time monitoring of the testing process, automatic judgment of the testing result, generation of a testing data recording report, even uploading of the report to a cloud server and the like on the LED driving power supply to be tested through the communication port, and the quality management capability of a manufacturer is greatly improved. The communication port may specifically adopt an RS485 communication port or the like.
This device still includes: the communication address setting switch is connected with the central control unit, the communication address setting switch can endow each load device with a unique hardware address code, namely, a plurality of load devices can be simultaneously connected to the same RS485 bus, a host computer is utilized to simultaneously issue setting parameter commands to all the load devices connected to the RS485 bus, and test data of each load device can be respectively collected, so that large-scale networking application of the load devices is realized.
The voltage acquisition unit includes: and the first operational amplifier is used for acquiring the output voltage of the LED backlight driving power supply in real time, performing analog-digital signal conversion through the first high-speed AD converter and finally sending the output voltage to the central control unit.
The current collection unit includes: the two poles of the current sampling resistor R1 and the current sampling resistor R1 are connected with a second operational amplifier, the second operational amplifier collects voltage in real time, the current of the load circuit is obtained through ohm's law, the current is converted into analog-digital signals through a second high-speed AD converter, and the analog-digital signals are finally sent to the central control unit.
The central control unit respectively controls each relay in a one-to-one correspondence mode through i triodes Q1-Qi, collectors of the triodes are connected with the corresponding relays in series, bases of the triodes are connected with the central control unit, emitting electrodes of the triodes are grounded, the central control unit controls the operation of the triodes, the triodes trigger the on-off of the relays again, when the relays are switched on, the load units are in short circuit and do not participate in the test work, when the relays are switched off, the load units are connected into a load circuit for testing and participate in the test work, and whether the on-off state or the off-state is determined according to the size of the LED backlight driving power supply to be tested.
The central control unit adopts a 32-bit MCU microprocessor and is used for completing the data acquisition and control system formed by the cores.
Referring to fig. 2, in actual production, the forward conduction voltage of the most commonly and widely used single LED is about 3.2V, and the forward conduction voltage of the most commonly used single rectifier diode is about 0.8V, so that four rectifier diodes D1-D4 are connected in series to obtain the same forward conduction voltage as that of the single LED1, and similarly, if a load circuit with N LEDs connected in series is required during testing, an equivalent circuit can be obtained by connecting N4 rectifier diodes in series. The rectifier diode is used for simulating the LED, the rectifier diode has volt-ampere characteristics similar to that of the LED, the LED is high in cost, short in service life under a test environment, weak in overcurrent resistance and high in luminance, the rectifier diode is a common electronic element, low in price, strong in overcurrent resistance, free of light emission and free of light pollution when being applied in a large scale.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and any indirect modifications, equivalent changes and modifications made to the above embodiment according to the technical spirit of the present invention by those skilled in the art are within the technical scope of the present invention.
Claims (10)
1. An improved load cell for testing an LED backlight driver power supply, comprising: the positive pole and the negative pole of the LED are sequentially connected with x rectifier diodes in series, wherein the forward conducting voltage of any adjacent m rectifier diodes on the series connection sequence is equal to the forward conducting voltage of a single LED, and x is an integral multiple of m.
2. The improved load cell for testing LED backlight driving power of claim 1, wherein m is 4.
3. An intelligent load device for testing an LED backlight driving power supply, comprising:
n rectifier diodes with positive and negative electrodes connected in series in sequence, wherein the forward conduction voltage of any adjacent m rectifier diodes on the series connection sequence is equal to the forward conduction voltage of a single LED, and n is an integral multiple of m;
the i relays are used for switching the rectifier diodes in a segmented manner, the rectifier diodes which are divided into one segment are a load unit, and the number of the rectifier diodes of the i load units is equal to or different integral multiples of m;
the central control unit is used for respectively and independently controlling the on-off state of each relay, the load unit is in short circuit when the central control unit is switched on, and the load unit is switched into a load circuit for testing when the central control unit is switched off;
and a voltage acquisition unit and a current acquisition unit.
4. The intelligent load device for testing the LED backlight driving power supply according to claim 3, wherein the device further comprises: and the operation input unit and the display unit are respectively connected with the central control unit to form an input and output interface for man-machine interaction.
5. The intelligent load device for testing the LED backlight driving power supply according to claim 3, wherein the device further comprises: and the communication port is used for the mutual communication between the central control unit and the upper computer.
6. The intelligent load device for testing the LED backlight driving power supply according to claim 3, wherein the device further comprises: and the communication address setting switch is connected with the central control unit and can give a unique hardware address code to each device, so that the large-scale networking application of the device is realized.
7. The intelligent load device for testing the LED backlight driving power supply according to any one of claims 3 to 6, wherein the voltage acquisition unit comprises: the first operational amplifier is used for being connected with two poles of the LED backlight driving power supply, collects the output voltage of the LED backlight driving power supply in real time, and sends the output voltage to the central control unit through the first high-speed AD converter.
8. The intelligent load device for testing the LED backlight driving power supply according to any one of claims 3 to 6, wherein the current collection unit comprises: and the two poles of the current sampling resistor are connected with a second operational amplifier, the second operational amplifier collects voltage in real time and obtains the current of the load circuit, and the current is transmitted to the central control unit through a second high-speed AD converter.
9. The intelligent load device for testing the LED backlight driving power supply according to any one of claims 3 to 6, wherein the central control unit is respectively connected with each relay in a one-to-one correspondence manner through i triodes, the central control unit operates to control the triodes, and the triodes trigger the on or off of the relays.
10. The intelligent load device for testing the LED backlight driving power supply according to any one of claims 3 to 6, wherein the central control unit adopts a 32-bit MCU microprocessor.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110329717.0A CN112904221A (en) | 2021-03-26 | 2021-03-26 | Improved load unit for testing LED backlight driving power supply and intelligent load device |
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| CN202110329717.0A CN112904221A (en) | 2021-03-26 | 2021-03-26 | Improved load unit for testing LED backlight driving power supply and intelligent load device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114708822A (en) * | 2022-04-12 | 2022-07-05 | 长沙硕博电子科技股份有限公司 | LED screen backlight constant-current short-circuit-prevention control system and short-circuit-prevention fault control method |
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2021
- 2021-03-26 CN CN202110329717.0A patent/CN112904221A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114708822A (en) * | 2022-04-12 | 2022-07-05 | 长沙硕博电子科技股份有限公司 | LED screen backlight constant-current short-circuit-prevention control system and short-circuit-prevention fault control method |
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