Planar Magnetic Technology for Headphones
Planar magnetic technology is being revived by a handful of specialized HiFi audio companies. These companies make headphones using old-fashioned planar drivers that provide an impressive sound quality.
This paper focuses on the fundamental characteristics of a planar magnetic device by studying winding conduction losses, leakage inductance and winding capacitance. In addition, a strategy for reducing these parasitic elements is proposed.
Low vertical height or low profile
Planar magnetics are more efficient and have a slimmer profile than wire-wound magnets. It also reduces leakage capacitance and parasitic capacitance. This technique allows for a smaller core to be utilized, which reduces the cost of the device. Additionally, it does not require any clamping of the magnets. This makes it perfect for power electronic devices.
Planar magnetic technology has the advantage of being smaller and lighter than traditional headphones. It can also handle a wider range of frequencies without distortion. This is due to the flat diaphragm that is employed in these devices, which is usually composed of a thin film and includes a conductor trace on it. The film can react quickly to audio signals and produce high levels of sound pressure easily.
The sound produced by these devices will be more acoustic and more detailed. This is why it is highly favored by audiophiles, specifically those who like listening to music in their workplace or at home. It is important to keep in mind however that a planar magnetic driver requires an amplifier that is powered and a digital audio converter (DAC) to perform effectively.
The resulting sound is much more natural and precise than the sound produced by dynamic drivers. Planar magnetic drivers are also capable of responding to changes in audio signals much faster, making them ideal for listening to music that is fast.
Despite their advantages, planar magnet drivers have a few disadvantages. Their high price can be partially due to the huge amount of magnetic material required to operate. Their weight and size can also be a problem particularly when they are being used as portable devices.
Wide band gap (WBG) devices
Wide band gap (WBG) semiconductors are a type of material that have better electrical properties than silicon-based devices. They can withstand larger current density, higher voltages, and lower switching losses. They are therefore ideal for optoelectronics and power electronic applications. Wide band gap semiconductors like gallium nitride and silicon carbide can provide significant improvements in performance, size and cost. They are also environmentally sustainable than conventional silicon-based products. These attributes make them attractive for satellite and aerospace manufacturers.
Planar magnetic drivers operate on the same principles as dynamic drivers. Conductors of electricity move between two magnets that are fixed when audio signals travel through them. However, instead of a coil bonded to a conical diaphragm, planar magnetic drivers use an array of conductors that are flat connected to, or embedded into a diaphragm-like film which can be made thin. Conductors are a set of coils' that sit on the diaphragm, and are placed directly between two magnets. This creates the push/pull effect which creates the diaphragm's to move.
This technology produces distortion-free music and provides a unique, pleasing sound. The uniform distribution of the magnetic force over the entire surface of the driver and the absence of a coil sitting behind the diaphragm cause it to move evenly and quickly, producing an extremely precise, detailed sound. The resulting sound is known as isodynamic, orthodynamic, or magnetically-incident.
However, headphones planar to their intricate design and price headphones that use planar magnetic drivers are generally more expensive than headphones with other driver technologies. There are some good and affordable choices, such as the Rinko from Seeaudio or S12 /Z12 by LETSHUOER, that were released recently.
Power electronics
Planar magnetics dissipate heat more efficiently than traditional wire wound components. This lets them handle more power without causing undue strain or audible strain. This makes them ideal for use in headphones. Planar magnetics are more efficient and also offer a greater power density. This technology is particularly designed for applications such as electric vehicle charging, battery management and military systems.
Compared to dynamic driver headphones, which utilize a diaphragm suspended by a voice coil, planar magnetic drivers operate using a different method. A flat array of conductors sits directly on the diaphragm and when an electromagnetic signal flows through the array, it triggers a push-pull interaction with the magnets on both sides of the diaphragm. This creates sound waves which move the diaphragm creating audio.
Planar magnetic devices are more efficient than conventional magnetics since they have a higher surface-to-volume ratio. They are able to disperse heat more efficiently, which allows for higher switching frequencies, while maintaining their maximum temperature ratings. They have lower thermal sensitivities when compared to wire-wound devices. This allows them to be utilized in smaller power electronics circuits.
Designers must consider several factors to optimize a planar booster inductor. These include the core design, winding configurations, losses estimation and thermal modeling. Ideal inductor characteristics include low winding capacitance, low leakage inductance, and easy integration into a PCB. It should also be able to handle high currents and have a compact size.
The inductor also needs to be compatible with multilayer PCBs with through-hole or SMD packaging. The copper thickness should be sufficiently thin to avoid thermal coupling and limit eddy-currents between conductors.
Planar winding based on Flex circuits
In planar magnetics, flex circuit-based windings can be used to create an extremely efficient resonance. They utilize one-patterned conductor layers that are a flexible dielectric film. They can be fabricated with a variety foils. Copper foil is a popular choice because it has excellent electrical properties. It is also processed to permit termination features both on the front and back. The conductors of a flex-circuit are joined by thin lines which extend beyond the edges on the substrate. This gives the flexibility needed for tape automated bonding. Single-sided flex circuits can be found in a variety of thicknesses and conductive coatings.
In a typical pair of planar headphones, a diaphragm will be sandwiched between two permanent magnets. The magnets vibrate in response to electrical signals that are sent by your audio device. These magnetic fields generate a sound wave that travels across the entire diaphragm's surface and creates a piston-like motion that prevents breakups and distortion.
One of the primary advantages of planar headphones is their capacity to reproduce a wider frequency range, especially in the lower frequencies. The reason for this is because they have a bigger surface area than traditional cone-type speakers, which allows them move more air. They can also reproduce bass sounds with a higher level of clarity and detail.
However, planar magnetic headphones are expensive to make and require a powered amplifier as well as a DAC to function effectively. Additionally, they are heavier and larger than standard drivers, making them difficult to transport and to fit into smaller spaces. Also their low impedance needs lots of power to drive them and can add up quickly when you're listening to music at a high volume.
Stamped copper winding
Utilizing stamped copper windings in planar magnetic technology can improve the window's utilization ratio and lower manufacturing costs. The technique involves placing grooves into the coil body to hold the windings in a layer-accurate location. This helps prevent deformations of the coil and increases the accuracy of the coil. It also reduces the amount of scrap produced during production and enhances quality assurance. This type of planar coil is typically used in contactor coils and relay coils. It can also be found in ignition coils and small transformers. It can also be used in devices with wire thicknesses up to 0.05mm. The stamping process produces an even coil with high current density. It also ensures that the windings are precisely placed on the coil body.
Unlike traditional dynamic drivers, which use a conductor voicecoil behind the diaphragm to create sound waves the planar magnetic headphones comprise a range of flat conductors placed directly on the thin diaphragm. When electronic signals are applied to these conductors, they vibrate, causing a pistonic motion that creates sound. As a result, planar magnetic headphones provide superior sound quality than other types of audio drivers.
This technology can boost the transducer's bandwidth. This is important, as it allows them to operate in a wider frequency range. It also reduces the power requirements of the driver.
Nevertheless, there are some disadvantages to this new technology. For instance, it could be challenging to create an ultra-thin diaphragm with a thin film that can withstand the high temperatures required for this kind of technology. However, manufacturers like Wisdom Audio have overcome this issue by introducing an adhesive-free solution that can withstand temperatures up to 725degF (385degC). This allows them to create audio with superior quality, without sacrificing durability and longevity.