Industry new

Transformer is a key device in DC/DC magnetic material design

In recent years, companies engaged in the design and manufacture of DC/DC magnetic materials have been under considerable commercial and competitive pressure in many areas of the electronics industry. Market demand has turned to small size, high density and higher efficiency products.
Regardless of cost, size or performance, transformers are a key part of DC/DC magnetic material design. Therefore, everyone is trying hard to optimize the device to match the development of advanced semiconductors and passive components.
Although traditional winding transformers are still used in many large form factor power applications, the emergence of several new technologies in recent years has brought significant benefits to DC/DC converter designs. One example is flat-plate transformers.
Stand-alone and embedded flat transformers. The stand-alone flat transformer is constructed using a planar copper lead frame or a copper wire of a printed board as a winding. This means that they take up much less space than traditional copper transformers on a stand. Precise copper lead frames or printed windings allow the design specifications to meet the requirements more accurately than the wire-wound transformers, and the level of repeatability between parts is also improved.
Etched copper lead frames or printed windings are stacked in the flat plate, and the high-frequency ferrite core constitutes the magnetic circuit of the transformer. This design makes it a very low profile transformer assembly. Realizing a large cross-sectional area copper conductor in a flat panel design makes high power density and high current design easier. The high surface capacity ratio of the plate winding and ferrite allows the product to have a good heat dissipation function.
Especially at high operating frequencies, high efficiency is a further key benefit of planar transformers. In the wirewound transformer, efficiency is adversely affected by the “skin effect”, that is, when high-frequency current passes through a cylindrical conductor, it forces the electrons to flow from the center to the edge to concentrate on the surface of the copper wire, thereby reducing the current through the conductor cross-sectional area.
From a point of view of completion and assembly, planar transformers also have advantages over wire wound transformers. Winding transformers usually require manual operation to strip the coating at the winding end and then solder or tin solder. The pressing of magnetic materials on planar transformers or the etched ends of copper sheets can often form surface posts to increase assembly speed and repeatability, thereby reducing costs. In combination with an embedded planar transformer, this advantage is even more pronounced, where the ferrite passes through the DC/DC magnetic material PCB and the windings spirally layer around the printed circuit board.
Although they take up more space than embedded designs, the popularity of stand-alone planar transformers has increased in recent years. Because the fully embedded transformer uses a DC/DC magnetic material circuit board as its own winding, each set of input/output voltages requires a different circuit board design. Moreover, for the embedded planar design, the overall cost is higher because a multilayer circuit board is required to etch the coil. Some hybrid designs use the main board as a primary winding, and then use a separate small PCB as a secondary to generate different output voltages. This design is also very common.
Although embedded designs achieve high power density and have good thermal performance to achieve space-saving features, magnetic materials, but for many applications, these advantages are limited by cost, lack of flexibility, and interchangeability. High production volume will offset the higher cost of embedded design to a certain extent.
More transformer designs. The existing transformer design is based on magnetic technology. In the future, the large-scale adoption of acoustic coupling technology will provide the potential for smaller transformer designs. At present, some low-power, high-output voltage DC/DC magnetic material designs have been implemented to some extent.
Acoustic transformers utilize the properties of piezoelectric materials to couple electrical energy through a vibrating structure. A magnetic material excites a resonant mode of the material and is then intercepted by a second secondary magnetic material and converted to a secondary voltage.
In other developments in transformer design, the use of extremely high operating frequencies can produce effective air coupling, so no ferrite is required. Combining transformers and other magnetic devices such as output chokes into the circuit is another big step, which will help reduce the overall form factor of the DC/DC design.
Finally, the development of new magnetic materials allows higher operating frequencies and low losses, which will help provide smaller transformers for a given power supply.
Obviously, winding transformers have become increasingly unsuitable for use in DC/DC magnetic materials and other applications. The difficulty of their large size, inefficiency, and inability to meet the reproducibility of parts means that they are rapidly being replaced by recent technologies.
Embedded and stand-alone planar transformers have their own advantages and disadvantages. The choice of one or the other in the design depends on the application needs. An innovation of tapped secondary (or primary) transformers and offers some advantages over traditional designs. Once again, the application will determine whether they are the most appropriate choice for a given design. In the future, the transition from magnetic transformers to acoustic transformers will seem to produce some exciting new products, and DC/DC magnetic material designers will increasingly choose.

PREVIOUS：Magnetic Materials Industry in China Faces UnNEXT：Application of Copper Soft Magnetic Alloy in