PCB Tech - ​Reasons why PCBA electronic transformers must be innovative

In the past 30 years, various types of electronic products have been developing in the direction of high frequency, high power, low loss and high cost performance, which has narrowed the living space of traditional EI and C core electronic transformers. Therefore, while the traditional type still accounts for a large share of the output value of PCBA electronic transformers in mainland China, it is necessary for Shanghai SMT processing to increase its pace of upgrading with reform and innovation. Otherwise, PCBA electronic transformers in the mainland Occupation will remain in the position of "working" for a longer period of time. The top level is the innovation of the three-dimensional transformer to the planar transformer. The volume and weight of the planar transformer is reduced by 80% compared with the traditional type. It has formed a product series of 5W-20kW/20kHz～2MHz, and its typical power value can reach 98%. The second level of update is the mass production of chip transformers. The height of the chip transformer is further reduced, and the flattening is basically completed. They are suitable for the requirements of low-voltage and high-current power supplies with currents above 100A. The structure of PCBA processing generally selects one primary winding and multiple magnetic cores to replace the traditional multiple windings of one magnetic core.

The third level of renewal is the successful development and planning of thin-film transformers. Due to the choice of thin film structure, the low height is better completed, generally less than 1mm, and the operating frequency exceeds 1MHz, reaching 10 MHz～100MHz. Thin film transformers can be made using integrated circuit technology, so the cost is not higher than that of chip transformers. Thin film transformers are the development direction of the widely used DC switching power supply transformers. From the perspective of application, the planning of electronic products is becoming more and more personalized and diversified, with more categories, varieties, and types. The planning and production of electronic transformers must be accustomed to such trends and guidelines. The planning and production of circuit board processing must pay attention to the following requirements: structural planning, the general trend is small, thin and light, suitable for PCB installation requirements. For electronic transformer planners, small, thin and light is the most difficult of the three forced components.

In order to meet the requirements of miniaturization, the first choice is to increase the operating frequency of the power supply. The current operating frequency is above 20kHz to 100MHz. Choosing a high operating frequency is accompanied by an increase in high-frequency loss and electromagnetic noise. This requires the selection of new high-end magnetic materials and anti-electromagnetic interference devices to overcome, which will complicate the planning of electronic transformers and power supplies. Electronic transformer planning should put operating power and production power in an important position. Improving the operating power and output power of electronic transformers is a concrete implementation of environmental protection and energy saving. In the electronic transformer planning, the operating power required for circuit board processing is: the power of the low-power DC switching power supply below 100W> 85%; the operating power of the medium and high-power DC switching power supply should be greater than 90%. The loss of electronic transformers and inductors accounts for about 15% of the power supply, so the operating power of the electronic transformers is required to be >95% to 98%. The no-load loss and no-load current of the PCBA electronic transformer are the main factors for the standby loss of electronic equipment. Therefore, the no-load loss of the electronic transformer is required to be less than 2%. To improve the working power of electronic transformers, it is necessary to solve the problems of less heat generation and faster heat dissipation. As with any other PCBA product, cost is a necessary issue for electronic transformer planning. In addition to being used to modern electronic equipment requirements in terms of low loss, small size, high power, stability and reliability, electronic transformers are also a necessary condition for market competition. To reduce transformer costs, planning is the foundation. The selection of original materials and the structure of the electronic processing plan play a leading role in the cost. Process equipment and process planning, online testing equipment and route planning, etc. should all be based on the lowest cost.