The development of miniature transformers is the demand of today's electronics and information technology. The miniaturization of transformers is an inevitable trend in the development of transformer technology.
From the current point of view, the small size and high power density of planar transformers with ferrite cores are the mainstream of micro-transformers. Thin-film transformers with micro-manufacturing technology are in the development stage, and the actual promotion and application are still individual cases. With the rapid development of electronic technology, ferrite planar transformers will still play a major role in larger power module power supplies.
Application of Planar Transformer Technology Planar transformers have been widely used in communications, notebook computers, automotive electronics, digital cameras, and digital televisions in the past 10 years since their inception. For example, a 560W power range DC-DC converter made of a planar transformer has been applied to the card-type board power supply of the telecommunication system. Due to the special electrical and mechanical environment in automobiles, more stringent requirements are imposed on the design and process of transformers. Planar transformers are used in the DC-DC converters of xenon arc lamp ballasts in mid-range cars. Secondly, the planar transformer for broadband transmission applications also shows a good development prospect.
In addition, the product variety of planar transformers has involved all aspects of conventional ferrite core transformers such as power transformers, bandwidth transformers and impedance matching converters. Due to its good consistency and small size, it is especially suitable for use in electronic equipment with small internal space and strict requirements for energy saving and heat dissipation. The application of planar transformers in the fields of national defense, aerospace, and aerospace that require extremely high weight and stability will also open up a new situation for the miniaturization of the system.
In short, miniaturization and planarization of inductive ferrite components will arouse people's interest in applications. It is believed that planar transformers will soon replace traditional transformers and gradually achieve large-scale production in certain high-tech fields.
Principle of Planar Transformer Structure
Planar transformers usually have 2 or more cylindrical cores of the same size. Now take the planar transformer with 2 magnetic cores as an example to introduce its structure, as shown in Figure 1. The two corners of each magnetic core column on the diagonal are connected by copper skins, and the copper skin is close to the inner wall of the magnetic core when passing through the magnetic core columns. Two magnetic cores are placed side by side, the two adjacent corners are welded with copper skin, and the copper skins on the two corners on an outer side of a magnetic core are welded together with a piece of copper skin. This is the secondary coil of the planar transformer. If the tap is drawn here, it is the center tap of the secondary coil; the copper skins on the two corners on the outer side of the other magnetic core are the two ends of the secondary coil of the planar transformer. This basically constitutes the main part of a planar transformer. Its secondary coil has only one turn, and it can have a center tap.
The planar transformer is composed of a copper lead frame and a flat continuous copper spiral wire, instead of a magnetic copper wire wound on a conventional ferrite core, the spiral wire is etched on a sheet of dielectric material coated with copper foil They are then stacked on a flat high-frequency ferrite core to form a transformer magnetic circuit. Then, the core material is bonded with a small particle size epoxy resin to minimize core loss. The high temperature resistant (130) insulation material in the spiral stack ensures a high degree of insulation between the windings.
Application of Planar Transformer
Planar transformers have been widely used in communications, notebook computers, automotive electronics, digital cameras and digital TVs in the past 10 years since their inception. For example, a DC-DC converter with a power range of 5 to 60W made of a planar transformer has been applied to the card-type board power supply of the telecommunication system. Due to the special electrical and mechanical environment in automobiles, more stringent requirements are placed on the design and process of transformers. Planar transformers are used in the DC-DC converters of xenon arc lamp ballasts and have been used in mid-range cars. Secondly, planar transformers for broadband transmission applications also show good development prospects.
In addition, the product variety of planar transformers has involved all aspects of conventional ferrite core transformers, such as power transformers, bandwidth transformers, and impedance matching converters. Due to its good consistency and small size, it is especially suitable for use in electronic equipment with small internal space and strict requirements for energy saving and heat dissipation. In the fields of national defense, aviation, aerospace and other areas that require extremely high weight and stability, the application of planar transformers will also open up a new situation for the miniaturization of the system.
A complete planar transformer also has a preset energy storage inductor. One end of it is often connected to the center tap, and there is a fixed copper plate on the upper and lower sides. They sandwich the magnetic core and the filter inductor, and at the same time serve as the rectifier power supply. Two poles and heat sink.
Summarized by Easybom (https://www.easybom.com/c/transformers).