Requirements of reliable performance of DC-DC module power supply on production environment
2022-09-04

In the modern high-tech era, the higher the reliability of DC-DC power modules, but AC-DC power conversion and DC-DC power conversion have gradually become module or integrated chip industry, and also gradually become an important part of various electronic equipment and industrial automatic control equipment. The quality and reliability of AC-DC power modules and DC-DC power modules also affect the reliability, inefficiency and maintenance rate of the whole equipment to a great extent.

Factors affecting the reliability of power supply products include design, process, management, testing and means, incoming materials, etc., which are the concerns of manufacturers of power supply modules. In fact, the reliability of the power module should not only ensure the optimization of various performance indicators, but also ensure that the production environment of the power module is clean and orderly, with good electrostatic protection measures and appropriate temperature and humidity. Only under such conditions can the power module really be called a power product with high reliability. With the continuous progress of society, electronic equipment plays an increasingly important role in industrial production, transportation, communication and other fields. The reliability of electronic equipment also determines the effective operation of various economic activities to a certain extent. Although the cost of power modules in electronic equipment is very low, they can be called the "heart" of electronic equipment. Failure of power modules may directly lead to paralysis of electronic equipment, Causing irreparable losses.

1、 Electrostatic protection: during the manufacturing, storage, transportation and assembly of components, due to the relative movement of instruments, materials and operators, electrostatic voltage may be generated due to friction. When the components are in contact with these charged bodies, the charged bodies will discharge through the components, causing device failure. Most modern integrated circuits use MOS circuits, and most power modules also use MOS tubes and integrated circuit chips. In the production of power modules, if electrostatic protection is not paid attention to, it will often lead to a high rate of component failure. Even qualified products may cause slight damage to MOS tubes and integrated circuit chips due to static electricity during production and manufacturing, thus affecting the service life and reliability of power modules. After the introduction of electrostatic protection system in the production environment (such as anti-static grounding of human body, anti-static grounding of floor, anti-static grounding of operating devices and instruments, etc.), the damage to MOS tubes and integrated circuit chips can be effectively avoided. Anti static damage of electronic components is a complex system engineering, which runs through the whole process of system or equipment development and production. From the procurement, packaging, transportation, inventory, installation, commissioning, testing of components to the use of users, the whole process, all-round and all personnel should follow a series of relevant measures to prevent electrostatic loss. Protection is a system engineering, which requires the input of equipment, personnel and effective management and system. It can be seen that the quality of an electrostatic protection system directly reflects the quality management level of an enterprise and shows the strength of an enterprise.

2、 Humidity: moisture can penetrate into porous materials, causing leakage paths between conductors, generating oxygen, moisture absorption of parts and components will reduce insulation resistance and isolation withstand voltage. However, excessive drying will also make some materials brittle, rough and even generate static electricity. Therefore, the production environment also has a certain impact on the reliability of the power supply. Most power modules are produced by soldering components onto small PCB (printed circuit board), and then potting the small PCB into the housing with resin. In the production process, if the humidity of the production environment is high, especially in the rainy season in the south, the moisture in the air will condense on the PCB board and components. Even if the bubbles are removed by the vacuum defoaming process when filling with resin, the moisture on the PCB board and components cannot be removed. When the power module is working at a high ambient temperature, the moisture on the PCB board and components will vaporize and expand, resulting in cracks on the power module, breaking the internal transformer wire, or introducing moisture from the outside, corroding the components inside the power module or causing a short circuit in the circuit inside the module. For occasions with high isolation voltage requirements, moisture on the PCB board and components will also reduce the isolation ability of the power module, and even cause the breakdown between the primary stages, resulting in serious consequences. Too low humidity will also cause too much dust to float in the air, affecting the quality of the power module. Too low humidity will also generate electrostatic charges due to personnel walking. Even if protected by the electrostatic protection system, it may cause electrostatic damage or soft breakdown of components, resulting in the same consequences as described above. The introduction of air conditioning system and dehumidification system in the production environment can keep the humidity of the production environment at an appropriate level and avoid adverse effects on the reliability of the power module due to moisture condensation or air drying. Influence of humidity on the product: moisture in the air is immersed in the resin. At the initial stage of heating, a small amount of water vapor pressure causes delamination at the resin interface. The pressure of water vapor increases with the welding temperature, causing the resin to expand. The water vapor is discharged through the package crack, creating a bad product.