Dcdc power supply module requirements for the production environment

In the modern high-tech era, rightdcdc power moduleThe higher the reliability performance, but AC-DC power conversion, dcdc power module conversion has gradually become a module or integrated chip industry, and gradually become an important part of various electronic equipment, industrial automatic control equipment, AC-DC power supply modules and dcdc The quality and reliability of the power module also greatly affects the reliability, failure rate and maintenance rate of the entire equipment.

Factors that affect the reliability of power supply products include design, technology, management, testing and methods, and incoming materials. These aspects are all concerned by manufacturers and users of power modules. In fact, the reliability of the power module must 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. The power supply module produced under the conditions can truly be regarded as a highly reliable power supply product. With the continuous progress of society, electronic equipment is playing an increasing role in industrial production, transportation, communications 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 module is very low in electronic equipment, it can be called the "heart" of electronic equipment. The failure of the power module may directly cause the paralysis of electronic equipment and cause irreparable losses.

1. Electrostatic protection: In the process of manufacturing, storage, transportation and assembly of components, due to the relative movement of equipment, materials and operators, electrostatic voltage may be generated due to friction. When the device is in contact with these charged bodies, it will be charged. The body will discharge through the device, causing the device to fail. Most modern integrated circuits use MOS circuits, and most power modules also use MOS transistors and integrated circuit chips. In the production of power modules, if you do not pay attention to electrostatic protection, it will often lead to a higher rate of component failure. Even products that have passed the test may cause slight damage to the MOS tube and integrated circuit chip due to static electricity during the manufacturing process, thereby affecting the life and reliability of the power module. The introduction of electrostatic protection systems (human body anti-static grounding, floor anti-static grounding and operating devices, anti-static grounding of instruments, etc.) into the production environment can effectively avoid damage to MOS tubes and integrated circuit chips. Anti-static damage to electronic components is a complex system engineering, which runs through the entire process of system or equipment development and production. From component procurement, packaging, transportation, inventory, installation, debugging, testing to user use, the whole process, all-round, and all employees should follow a series of related measures to prevent static electricity losses. Protection is a systematic project, which requires investment in equipment, personnel, and effective management and systems. It can be seen that the quality of an electrostatic protection system directly reflects the quality management level of an enterprise and is a demonstration of the strength of an enterprise.

2. Humidity: Humidity can penetrate into porous materials, causing leakage paths between conductors and generating oxygen. Moisture absorption of parts reduces insulation resistance and isolation withstand voltage. However, excessive drying can also make certain materials brittle, rough surface, and even generate static electricity. Therefore, the production environment will also have a certain impact on the reliability of the power supply. Most power modules are produced by soldering components on a small PCB board (printed circuit board), and then potting the small PCB board into the shell with resin. During the production process, if the production environment has high humidity, especially during the rainy season in the south, the moisture in the air will condense on the PCB board and components. On, even when the resin is potted, the bubbles are removed by the vacuum defoaming process. The moisture on the PCB board and components cannot be removed. When the power module is working at a higher ambient temperature, the moisture on the PCB board and components vaporizes and expands, causing cracks in the power module, breaking the internal transformer wire, or introducing external moisture, corroding the internal components of the power module or causing damage. The circuit inside the module is short-circuited. For occasions with higher isolation voltage requirements, the moisture on the PCB board and components will also reduce the isolation capability of the power module, and even cause breakdown between the primary and secondary, resulting in serious consequences. Too low humidity will also cause too much dust to float in the air, which will affect the quality of the power module. Too low humidity will also generate electrostatic charge due to the movement of people. Even if it is protected by the electrostatic protection system, it may also cause electrostatic damage or soft breakdown of the components, resulting in the same consequences as described above. The introduction of air conditioning systems and dehumidification systems in the production environment can keep the humidity in the production environment at an appropriate level and avoid adverse effects on the reliability of the power module due to moisture condensation or excessive air drying. The effect of humidity on the product The moisture in the air is immersed in the resin. At the beginning of heating, a small amount of water vapor pressure causes the delamination of the resin interface. The pressure of water vapor increases with the welding temperature, which causes the resin to expand and the water vapor permeates the package. Cracks are discharged, creating product defects.

3. Temperature: The temperature of the production environment also needs to be strictly controlled. Both high temperature and low temperature will affect the components to different degrees.

3.1 The high temperature and high temperature environment will change the electrical performance parameters such as the resistance, inductance, capacitance, and electric power series in the power supply, which will soften the insulator and cause the insulation failure; the movable element may be blocked due to expansion and cause the structure to fail, and the surface will be painted. Bubbles, oxidation and other chemical reactions accelerate, lubricant viscosity decreases and evaporates and loses lubricity; due to physical expansion, the wear of moving parts increases and its structural strength decreases.

3.2 The low temperature and low temperature environment will make the plastic and rubber of the power supply lose its flexibility and become brittle. When there is moisture, it will freeze, and the lubricant will become gum and sticky and lose its lubricity; the surface of the coating will be cracked; due to physical shrinkage Invalidate the structure, change the electrical and mechanical functions, etc.

3.3 Temperature control power modules, especially small-sized 1W and 2W power modules, often use magnetic winding transformers with an inner diameter of less than 5mm. Winding such transformers can only be produced by hand. When the production temperature is high, the palm of the production staff will Sweat. When winding the transformer, the sweat on the hands will remain on the transformer. The moisture and salt in the transformer will damage the patent leather of the transformer, reduce the insulation capacity of the transformer, and potentially affect the reliability of the power module. Install the air-conditioning temperature adjustment system in the production workshop to ensure that the workshop temperature is maintained at about 26 degrees, so that the production staff have a cool and comfortable environment, so that reliable quality power module products can be produced.

4. Dust: A lot of dust will scratch the power supply, wear the finishing surface, cause pores to be blocked, lubricants are contaminated, insulating parts are contaminated, corona passages are generated, and electrical performance is reduced. If the production environment is not clean, the dust floating in the air will fall on the PCB board, and the components will be soldered. The situation of false soldering will greatly increase, which will not only affect the production qualification rate of the product to a certain extent, but also affect the reliability and product quality of the product. Life-span causes a fixed impact. Paying attention to the cleanliness of the production environment and doing a good job of 5S management is a guarantee to ensure the production of reliable and reliable products. The weather in the north is more dusty and dusty than in the south, so more attention must be paid to control. Air filtration and sealing, smoke exhaust systems and other methods can be used to solve the problem.

V. Storage and custody: improper storage and custody is another important reason for the decrease in reliability or failure of components, and attention must be paid and corresponding measures must be taken. If the temperature and humidity of the warehouse should be controlled within the specified range, use a moisture-proof box, pay attention to moisture and static electricity, and prevent harmful gases from being present, and re-inspect regularly. The container for storing the components should be made of materials that are not easy to be charged with static electricity and not easy to cause chemical reactions of the components, and the sensitive components should be checked regularly. Electronic raw materials should also be handled with care and handling. Ceramic capacitors and magnetic materials are all easily broken raw materials. Pay special attention when handling and handling.