Planar transformers

Advantages and features of planar magnetic components

Planar transformers were first developed in the late 80’s, but because of the complex of manufacturing techniques was not widely available. Modern production technology of planar transformers also can not be called simple, but thanks to the continuous improvement process, the cost of planar transformers decreased and this has allowed them to compete in the market of power supplies.

Planar transformers are an excellent alternative to conventional transformers when the need arises in the small-sized magnetic components.

Planar transformer can act as external components in the form of single-layer printed circuit boards or as small multilayer board.

Advantages of planar magnetic components

The main advantages can be described as follows:

1. Have a very small size. With this planar components are promising for use in rack-mount and portable equipment with a high density mounting.
2. Suitable for the development of high power converters impulse. Copper ac has a small amount of losses and due to the high coupling coefficient becomes possible to more efficient conversion.
3. High density power throughput. Is due to a good temperature characteristics.
4. Have excellent repeatability properties. Repeatability values of parasitic parameters ensures high switching frequencies and create a resonant circuit.
5. 98% efficiency. If the design is well cooled, it allows it to transmit power from tens of watts to several kilowatts.
6. Operating voltage between the windings is more than 1000V.
7. Opportunities to increase the capacity of the transformer windings by using packages.

Technology features

The planar manufacturing technology provides that inductive components during manufacture of the windings serve as tracks on a printed circuit board or portions of copper which is applied by a printing method, and separated layers of insulating material. Also winding can be constructed from multilayer printed circuit boards.

In any case, the windings are placed between the small-sized ferrite cores. Mounted planar components situated closest to conventional inductive components and can be used instead of the usual details at the one- or multilayer printed circuit boards.

To reduce the height of the mounted component, it is necessary to place the core in the cutout of the printed circuit board so that the winding lies on the surface of the board.

Step forward hybrid type displays, in which a portion of the winding is embedded in the motherboard, and the others are on a multilayer board, which is connected to the motherboard.

At the same time, the motherboard must have openings for the ferrite core.

The latter type of planar components has a winding, fully integrated into a multilayer printed circuit board.

Differences between traditional planar transformer and coil transformers

Planar transformers have a relatively large effective area and cooling them much easier to cool. You can use natural, forced, liquid-cooled, single-sided or double-sided radiator.

Small spread of electrical parameters from device to device.

Errors in the parameters of a planar transformer is hundreds of times smaller than a traditional transformer errors.

Where are planar transformers used?

Planar transformers have been applied in telecommunication systems, aircraft on-board systems, computers, power supply sources, welding machines and induction heating system. In general, planar transformers may be used wherever there is a need for a power transformer, which would have a high efficiency, and at the same time has small dimensions.