Testing device for simulating backlight of product by using multi-path series LED (light-emitting diode)

Abstract

The utility model aims to provide the testing device which is simple in operation, low in cost, complete in function and capable of efficiently evaluating the performance of the LED backlight system. The circuit comprises an LED series module, a current sampling module, a channel switching module, a signal amplification module and a signal processing module which are connected in sequence, the LED series module is connected with a product, the LED series module comprises a plurality of groups of LED modules which are arranged in parallel, each LED module comprises five groups of LEDs which are arranged in series, and the signal processing module is connected into an external upper computer. The utility model is applied to the technical field of backlight simulation tests.

Description

Technical Field

[0001] The utility model is applied to the technical field of backlight simulation testing, and particularly relates to a testing device that utilizes multiple LEDs in series to simulate product backlight. Background Art

[0002] With the rapid development of science and technology, LED has the advantages of high efficiency, energy saving, and environmental protection, and has been widely used in lighting, display, backlighting and other fields. Especially in product backlighting, LED has become the preferred light source for backlighting systems due to its long life, high brightness, and low heat generation. However, with the increase in the complexity and functionality of product design, the performance and quality requirements of LED backlighting systems are becoming increasingly stringent.

[0003] In the development and production of LED backlight systems, backlight testing is a key step in ensuring product performance and quality. Traditional LED backlight testing methods often use a single LED or a small number of LEDs for testing, which cannot simulate the multiple LEDs in series in actual products, resulting in a large difference between the test results and actual usage, making it difficult to accurately evaluate product performance and quality.

[0004] The prior art has the following disadvantages:

[0005] 1. Limited test scope: Traditional testing methods usually only test a single LED or a small number of LEDs, which cannot cover the complex situation of multiple LEDs in series in actual products, resulting in the test results being unable to fully reflect the overall performance of the product backlight system;

[0006] 2. Insufficient test accuracy: Due to the limitations of test equipment and methods, existing test solutions are often unable to accurately measure and evaluate the key performance parameters of LED backlight system brightness, which can easily lead to product quality problems and affect user experience;

[0007] 3. Complicated test process: Some test solutions require manual setting and adjustment of test parameters, which is complicated and time-consuming. This not only reduces test efficiency, but also may lead to inaccurate test results due to human error.

[0008] 4. High testing costs: Although some advanced testing equipment and technologies can provide more accurate test results, they are often expensive, increasing the cost burden of product research and development and production.

[0009] 5. Limited data analysis and processing capabilities: Existing testing solutions may have deficiencies in data collection and analysis, and cannot effectively extract useful information from large amounts of test data, providing limited support for product performance optimization and improvement.

[0010] In summary, the existing simulation product backlight test solutions have obvious shortcomings in the test environment, test range, test accuracy, test process, test cost, and data analysis and processing capabilities. Therefore, it is necessary to provide a test device that uses LED multi-channel series simulation product backlight, which is simple to operate, low cost, complete in function, and can efficiently evaluate the performance of LED backlight systems. Utility Model Content

[0011] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a testing device for simulating product backlight by connecting multiple LEDs in series, which is simple to operate, low in cost, and has complete functions and can efficiently evaluate the performance of an LED backlight system.

[0012] The technical solution adopted by the utility model is: the utility model includes an LED series module, a current sampling module, a channel switching module, a signal amplification module, and a signal processing module connected in sequence, the LED series module is connected to the product, the LED series module includes several groups of LED modules arranged in parallel, the LED module includes five groups of LEDs arranged in series, and the signal processing module is connected to an external host computer.

[0013] As can be seen from the above scheme, this application simulates the backlight system in the actual product by precisely controlling the series working state of multiple LEDs based on the electrical and optical characteristics of LEDs. The test scheme includes multiple links such as the setting of test parameters, the collection and analysis of test data, etc., which can comprehensively evaluate the key performance indicators of the LED backlight system such as brightness, uniformity, color temperature, power consumption, etc., and can simulate the backlight test of the multi-channel series working state of LEDs in actual products, which is of great significance for improving the research and development efficiency of the LED backlight system and ensuring product quality. It is intended to achieve a comprehensive and accurate evaluation of the performance of the product backlight system through the LED multi-channel series simulation product backlight test scheme, and provide strong support for the research and development and production of the LED backlight system. At the same time, the test scheme also has the advantages of simple operation and low cost, and is suitable for the research and development and production of various LED backlight systems. Compared with the traditional test scheme test, this application has the advantages of small size, simple circuit, easy integration and covers the complex situation of multi-channel LED series connection in actual products.

[0014] A preferred solution is that the current sampling module includes a plurality of groups of sampling resistors, and each group of the sampling resistors is connected to a corresponding LED module.

[0015] A preferred solution is that the channel switching module includes a multiplexer, the two ends of the sampling resistor are respectively connected to the LED_IO_CURRENT+ pin and the LED_IO_CURRENT- pin of the multiplexer, and the OUTPUT_CURRENT+ pin and the OUTPUT_CURRENT- pin of the multiplexer are connected to the corresponding pins of the signal amplification module.

[0016] A preferred solution is that the signal amplification module includes an instrument amplifier, the same-direction input terminal of the instrument amplifier is connected to the OUTPUT_CURRENT+ pin of the multiplexer, the reverse input terminal of the instrument amplifier is connected to the OUTPUT_CURRENT- pin of the multiplexer, and the output terminal of the instrument amplifier is connected to the signal processing module. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural block diagram of the utility model;

[0018] Figure 2 It is a principle block diagram of the utility model;

[0019] Figure 3 is a circuit schematic diagram of the LED series module and the current sampling module;

[0020] Figure 4 is a circuit schematic diagram of the channel switching module;

[0021] Figure 5 is a circuit schematic diagram of the signal amplification module. DETAILED DESCRIPTION

[0022] like Figures 1 to 3 As shown, in this embodiment, the utility model includes an LED series module 1, a current sampling module 2, a channel switching module 3, a signal amplification module 4, and a signal processing module 5 connected in sequence, the LED series module 1 is connected to the product, the LED series module 1 includes several groups of LED modules arranged in parallel, the LED module includes five groups of LEDs arranged in series, and the signal processing module 5 is connected to an external host computer.

[0023] The LED series module 1 is composed of ROHM model: CSL0406WBCW, which is a white light LED with high brightness and small size; the forward current is as high as 30mA, the forward voltage Vf=3.2V, and a single circuit is composed of five LEDs in series, and the total voltage is about 16V. This combination meets the power supply voltage provided by the product, and adopts a six-group parallel mode, which meets the test requirements in most cases.

[0024] The signal processing module 5 is the FPGA part inside the MCU; the signal processing module 5 processes the obtained voltage value by the FPGA inside the MCU and calculates and outputs the current value in each series path; the LED series module 1 simulates the backlight group of the product, and the number of series light groups of different products is different. This application sets up six groups of LED modules, which are sufficient to cover the needs of most products; the current sampling module 2 completes the current collection of each group of lights through high-precision sampling resistors, and the selection of high-precision sampling resistors ensures the accuracy requirements of the test; the channel switching module 3 is controlled by the MCU to complete the switching measurement of the collection signals of multiple light groups; this application collects the voltage across the sampling resistor. Since the voltage across the sampling resistor is small and inconvenient to process, the voltage signal is amplified by the signal amplification module 4.

[0025] like Figure 3 As shown, in this embodiment, the current sampling module 2 includes several groups of sampling resistors R1, and each group of the sampling resistors R1 is connected to the corresponding LED module. The current sampling module 2 uses YAGEO's high-precision, high-stability sampling resistor RT0603BRD073R83L, which is packaged in 0603 and has a small size, an accuracy of ±0.1%, and a resistance temperature coefficient of 25ppm / ℃.

[0026] like Figure 4 As shown, in this embodiment, the channel switching module 3 includes a multiplexer U4, the two ends of the sampling resistor R1 are respectively connected to the LED_IO_CURRENT+ pin and the LED_IO_CURRENT- pin of the multiplexer U4, and the OUTPUT_CURRENT+ pin and the OUTPUT_CURRENT- pin of the multiplexer U4 are connected to the corresponding pins of the signal amplification module 4.

[0027] The channel switching module 3 is composed of the ADG1408 multiplexer of Analog Devices, which is a single-chip iCMOS analog multiplexer with 8 built-in single channels. ADG1408 switches one of the 8 inputs to the common output according to the address determined by the 3-bit binary address lines A0, A1 and A2. And an EN input is provided to enable or disable the device. When disabled, all channels are turned off. It can be replaced with a 2-, 4-, or 16-channel multiplexer according to actual needs; this switch has ultra-low on-resistance and on-resistance flatness, on-resistance: 4Ω, on-resistance flatness: 0.5Ω; and a continuous current of up to 190 mA; rated power supply voltage: ±15 V / 12 V / ±5 V; 3 V logic compatible digital input, VIH = 2.0 V, VIL = 0.8 V.

[0028] like Figure 5 As shown, in this embodiment, the signal amplification module 4 includes an instrument amplifier U6, the same-direction input terminal of the instrument amplifier U6 is connected to the OUTPUT_CURRENT+ pin of the multiplexer U4, the reverse input terminal of the instrument amplifier U6 is connected to the OUTPUT_CURRENT- pin of the multiplexer U4, and the output terminal of the instrument amplifier U6 is connected to the signal processing module 5.

[0029] The signal amplification module 4 is composed of AD8253 of ADI. AD8253 is a digital programmable gain instrumentation amplifier with GΩ input impedance, low output noise and low distortion. It is suitable for interfacing with sensors and driving high sampling rate analog-to-digital converters (ADCs). It has a high bandwidth of 10 MHz, a low total harmonic distortion (THD) of −110 dB, and a fast settling time of 0.001% of 780 ns (maximum). The guaranteed offset drift and gain drift are 1.2 µV / °C and 10 ppm / °C (G = 1000), respectively. In addition to having a wide input common-mode voltage range, the device also has a high common-mode rejection capability of 100 dB from DC to 20 kHz and G = 1000. The combination of precise DC performance and high-speed capability makes the AD8253 suitable for data acquisition applications. In addition, this single-chip solution can simplify design and manufacturing, and improve instrument performance by maintaining a high matching of internal resistors and amplifiers. The AD8253 user interface consists of a parallel port, and the user can use two different methods to set the gain. The input can be used to latch the 2-bit word sent through the bus. Another method is to use the transparent gain mode, and the gain is determined by the logic level state of the gain port. There are four gain positions: 1, 10, 100, and 1000, which are controlled by two GPIOs of the MCU. In this circuit, resistor R33 and capacitor C18, resistor R35 and capacitor C17 form an LPF filter to ensure the stability of the input voltage of the op amp. The function of capacitor C16 is to eliminate the differential interference of the signal.

[0030] In this embodiment, the MCU processes the output signal, the circuit is simple, and it is easy to implement and expand; the channel switching module 3 uses an electronic switch, which can flexibly switch the current collection of different lamp groups.

Claims

1. A test device for simulating product backlight by connecting multiple LEDs in series, characterized in that: It comprises an LED series module (1), a current sampling module (2), a channel switching module (3), a signal amplification module (4), and a signal processing module (5) which are connected in sequence. The LED series module (1) is connected to a product. The LED series module (1) comprises a plurality of groups of LED modules arranged in parallel. The LED module comprises five groups of LEDs arranged in series. The signal processing module (5) is connected to an external host computer.

2. A test device for simulating product backlight by using multiple LED series connections according to claim 1, characterized in that: The current sampling module (2) comprises a plurality of groups of sampling resistors (R1), and each group of sampling resistors (R1) is connected to a corresponding LED module.

3. A test device for simulating product backlight by using multiple LEDs in series according to claim 2, characterized in that: The channel switching module (3) comprises a multiplexer (U4), the two ends of the sampling resistor (R1) are respectively connected to the LED_IO_CURRENT+ pin and the LED_IO_CURRENT- pin of the multiplexer (U4), and the OUTPUT_CURRENT+ pin and the OUTPUT_CURRENT- pin of the multiplexer (U4) are connected to the corresponding pins of the signal amplification module (4).

4. A test device for simulating product backlight by using multiple LEDs in series according to claim 3, characterized in that: The signal amplification module (4) comprises an instrument amplifier (U6), the same-direction input end of the instrument amplifier (U6) is connected to the OUTPUT_CURRENT+ pin of the multiplexer (U4), the reverse input end of the instrument amplifier (U6) is connected to the OUTPUT_CURRENT- pin of the multiplexer (U4), and the output end of the instrument amplifier (U6) is connected to the signal processing module (5).

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