Electronic load and its application in testing equipment

Preface

With the development of the electronics market, its prospects are undoubted, and the electronic measuring instruments and equipment that complement it are also widely used. As for the DC electronic loads widely used in the fields of LED driving, power module testing, charger production and UPS production, it has become an indispensable test equipment in these fields.

1. Overview of Electronic Load

1.1 Definition of Electronic Load and Its Application Examples

Electronic load, as the name implies, is a "load" function implemented by electronic devices, and its output port conforms to Ohm's law. Specifically, electronic load is a device that controls the conduction of internal power devices MOSFET or transistors to dissipate power and consume electrical energy.
Electronic loads generally have multiple modes such as constant current, constant voltage, constant resistance, constant power, short circuit and dynamic load, which can simulate various load conditions.

Application examples of electronic loads:
(1) LCD and other computer component manufacturers: electronic loads can be used to test and age their internal power supply modules;
(2) Switching power supply and LED manufacturers: generally, electronic loads can be used to test parameters such as power stability, load stability, output voltage adjustment and transient characteristics of DC power supplies. (For power supplies with multiple outputs, a combination of accessories can be used for testing);
(3) Adapter/charger manufacturers: It is important to test the output voltage and current adjustment capabilities of battery adapters, which will ensure that the equipment is powered and the battery is charged correctly. CC and CR working modes can be used for conventional performance testing, and OCP and SHORT functions can be used to test the protection action of the product. The adjustment time and charging time of the charger can be tested by the load pull time.

1.2 Market situation of electronic loads

In the field of electronic manufacturing and application, whether it is research and development, production, quality inspection or maintenance, an instrument must be used - electronic load. As a professional instrument for measuring various power supplies, the market of electronic load is relatively professional. Looking at the entire electronic load market, although there are not many competing brands, there are not few, and each brand has its own characteristics. The current mainstream brands are:
At the current stage of electronic load development, the technology is already very advanced, which is very in line with the development needs of the current electronic manufacturing and application market: it is powerful and can automatically test, simulate and overload test, and can also perform sequence tests; it is flexible to operate, and through the fully graphical interface of the operating software, it is more convenient for users to perform various data analysis; it is easy to integrate, not only can it form an automatic test system with high-speed data acquisition equipment, but also can provide all-round protection for the equipment being tested.

1.3 Functions of electronic loads

Electronic loads are widely used as testing equipment in the field of electronic manufacturing. Due to their powerful testing functions, they are suitable for various power supplies, LED drivers, batteries, chargers and other fields.

★ Intelligent functions. The intelligent functions of electronic loads enable the load itself to automatically complete product testing and support sequence dynamic testing. At the same time, they can continuously, pulse, flip and simulate arbitrary waveform dynamic load.

★ Sequence function. In complex application environments such as electronic product development, production line product aging, and quality inspection, the electronic load edits a complex test sequence by itself to simulate various changes in the load input and perform automatic testing functions. Especially in the overall test of power products, various test functions can be set as a sequence, and various trigger sources can be used for flexible automatic testing.

★ Transient function. This function refers to the electronic load module switching between two different values ​​in the same function, which can be used to test the dynamic characteristics of the power supply and conduct all-round dynamic index tests of various power supplies.

This function operation can have three modes: continuous, flip and pulse, and can quickly switch between the main value and the transient value. At the same time, the constant voltage, constant current, and constant resistance rising slope and falling slope can be flexibly set. Users can also use this function to easily change the slope of change to simulate complex load behaviors.

★Simulation programming function. When the power supply under test needs to be loaded with irregular dynamic loads (non-trapezoidal changes), this function can be used to achieve more simulated load conditions.

★Internal status monitoring function. In ATE test systems, production lines, quality inspections, etc., electronic loads implement functional tests based on multiple electronic loads, and monitor actual test results to complete product quality control. Users can monitor the working status of the electronic load in real time through the monitoring signal terminal, monitor the difference between the actual value and the load display value, and the execution status of the dynamic load change, and it is very convenient to use an external digital voltmeter or oscilloscope to monitor the voltage and current values ​​of the load.

★Low voltage operation function. The low voltage operation function of the electronic load is powerful, which can achieve true zero voltage load and full current load voltage.

★Protection function. The electronic load product fully implements internal (load protection) and external (device protection) protection, and can provide comprehensive and effective protection in terms of overvoltage, overcurrent, overpower, overtemperature, low voltage and voltage reverse.

2. Application of electronic load in equipment testing

Electronic load is a widely used test equipment in the field of electronic manufacturing and application. Now we can illustrate it through examples. For example, it is often used in the hot spot test of solar modules. For

example, outdoor test of the temperature difference of the hot spot module cell. Place the unshaded module outdoors and test its IV characteristics and the current Imp of the maximum power point under the irradiation of a radiation source of not less than 700W·m-2. Or short-circuit the module and let the module be stable under the irradiation of not less than 700W·m-2. Use an infrared thermal camera to measure the hottest cell and record its temperature. Under the same irradiance, the change of irradiance does not exceed 5% in this process. Use the positive and negative poles of the electronic load to connect the positive and negative poles of the module.

The FT6600A series multi-channel programmable DC electronic load of Feisi Technology has four test modes: constant current, constant voltage, constant resistance and constant power. In general, the constant current test mode is selected to facilitate the input of different component working currents. The purpose is to test the hot spot effect of the cell under different currents and record its heating conditions, so that it is convenient to formulate the requirements for the hot spot temperature difference of the finished solar photovoltaic components for delivery, and it is also convenient to measure various hot spot conditions of the components under continuous irradiance indoors. For example: place the component in a steady-state simulator, the radiation source is a steady-state solar simulator, the irradiance is set to 1000W·m-2, the unevenness does not exceed ±2%, and the instantaneous instability is within ±5%, and the hot spot is tested.

The FT6600A series electronic load can save costs for customers and form a test platform more conveniently. It is also equipped with a functional test software with virtual instrument functions, through which reports can be printed, images can be generated, reports can be exported, and data can be saved, which is convenient for intuitive analysis, recording and testing of the generated reports. Therefore, it is very convenient to generate a series of graphics under this irradiance level. Setting different currents through the electronic load and analyzing the hot spot heating under this current provide good graphics and data.

3. Conclusion

With the continuous progress of science and technology, and the development of electronic manufacturing and application fields, people's requirements for the various performance of electronic loads are also increasing. At the same time, they also hope that electronic loads can provide more help in improving the quality of their products in the electronic field. This requires the majority of electronic load manufacturers to improve the functions of their products to meet the needs of the majority of users.