The influence of the specification of the power adapter mechanism on the size of the transformer

　　The influence of the specification of the power adapter mechanism on the size of the transformer

　　Power adapter reliability and accelerated aging test

　　Reliability definition of air purifier power adapter

　　The so-called reliability of the power adapter is the ability to complete the specified function (ie normal operation) under the specified conditions and within the specified time. If the specified conditions or the specified time are exceeded, the power adapter may not work reliably, or even shorten its life.

　　Prescribed conditions-the environmental conditions, load size and working method of the circuit when it is working.

　　Specified time-the working time of the circuit to complete the specified function, that is, the time of normal work.

　　The specified function-the performance technical index of the circuit.

　　Through the use of various environmental test equipment to simulate the high temperature, low temperature, high temperature and high humidity, and temperature changes in the climatic environment, accelerate the reaction of the power adapter in the use environment to verify whether it meets the expectations in the research and development, design, and manufacturing Quality objectives, so as to evaluate the power adapter as a whole to determine the reliability life of the power adapter.

　　Life/failure rate curve (bath tub curve) life curve(bath tub curve)

　　The life/failure rate curve refers to the change of reliability of the small power adapter during the entire life cycle from the input to the end of life. Practice has proved that most failure rates are a function of time. A typical failure curve is called a bathtub curve. The shape of the curve is high at both ends and low in the middle. It has obvious stages and can be divided into three stages: the juvenile failure period, Stable failure period, elderly failure period.

　　Infant mortality:

　　Due to the production process, the materials used, or the design and other reasons, some defects caused a certain percentage of failures in the sample within a short time of use.

　　Stable failure period/random failure period:

　　During the stable working period of the device, most of the period, the performance gradually degrades with the spontaneous aging cycle, and the failure rate distribution can be modeled by different materials and processes. The general obituary is a stable, or slowly rising curve.

　　Elderly failure period (wear out):

　　The device reaches the end of its service life, and due to the aging of the inherent material, a large proportion of failures begin to occur.

　　Reliability requirements and accelerated aging of power adapters

　　The reliability of the universal power adapter needs to meet: under 24h operation, 2 restarts a day, average 80% data load, less than 200 plugs and unplugs, 60C 60%RH environment, standard voltage, current, standard bit rate, 10 years of cumulative failure The rate is less than 20%.

　　The optical communication industry is a branch of the electronics industry, and its reliability must also meet the above conditions. In the verification of the reliability of the actual power adapter, we usually use the user conditions that exceed the limit, that is, the accelerated condition or the stress condition to perform the experiment, that is, through accelerated aging, the equivalent shortened life span is used to reduce the experimental time, so as to reduce the experimental time as soon as possible The adapter was introduced to the market. There are a variety of accelerated aging models, which convert the actual life requirements into the stress conditions and experimental duration in the model, including:

　　Thermal model thermal effective: Arrheniusmodel, JMAmodel, is the theoretical basis of HTOL/HTS.

　　Thermo-mechanical model Thermo-mechanical: Norris Landzberg model, which is the theoretical basis of TC/TS.

　　Thermo-moisture model Thermo-moisture: Peck’s, Shirley, Reich-hakim, Lawson, is the theoretical basis of DH.

　　Through the reliability experiment method, the power adapter is evaluated as a whole to verify whether the power adapter has reached the expected quality goals in R&D, design, and manufacturing. Treating the power adapters that fail in the aging experiment with caution and focusing on the analysis of the reasons for the failure will be of great help to improving the quality of the power adapter.

Read recommendations:

24W European standard

Dc Power Supply 12v 2A 5V 20A switching power supply pcb design

AC 90-264V Open Frame Switching Power Supply 20W Bare Board PCB Module DC 12V 1.75A

Design of high-power and high-stability power adapter

Apple original 29W power adapter disassembly evaluation