Electromagnetic coil systems are carefully made up of conductive material that comes in the form of coils, spirals, or helices formed by a single-layer conduction wire wound in a specific pattern to address specific electrical needs. The coil geometry and building method depend on the intended inductance and resistance and on the magnetic field strength. There are two more specialised methods: bifilar and trifilar winding, where separate insulated conductors are wound in parallel multiple times.
Bifilar-Wound Coils
A bifilar-wound coil is one with two separate, adjacent windings realized with two insulated conductors wound parallel to each other.
Trifilar-Wound Coils
A trifilar-wound coil is constructed by winding three strands of wire together, enabling unique electrical characteristics and multi-conductor functionality.
The advantages of Bifilar and Trifilar Coils
The benefits of bifilar or trifilar coils are the following:
- Personalised Current flow patterns
The design flexibility they produce enables the current to be made to flow in the same or opposite ways, which can either amplify the potential differences or cancel magnetic effects depending on the situation.
- Better Substitute for Wire‑Wound Resistors
Bifilar coils may come in effect as superior operating wire-wound resistors, particularly where inductive behavior is of importance.
- Wasteful no more Magnetic Flux Management
They provide an easy method of controlling or clearing energy stored in stray magnetic flux, useful in small or fine-pitch circuits.
- High Degree of Micro‑Manufacturing
The bonding technology is a proprietary thermo-pressure technology that provides high-temperature controlled soldering of the finest acceptance of wires–to a precise spec that is non-oxidizing, best heat conductivity, and durable lasting quality connections.
Challenges in Producing Micro Bifilar and Trifilar Coils
Several key challenges that need to be addressed when designing and manufacturing micro-scale bifilar or trifilar coils:
- Mass Production In Economics
Laying out prototypes for low-cost manufacturing in large volumes represents a major challenge
- High‑Reliability Connections
It is necessary to guarantee a long-lasting connection that is hard to break by oxidation, excellent conductivity, and good reliability, which is challenging using conventional soldering.
- Very Tight Tolerances
Physical and electrical tolerance during manufacturing of these components stand small and difficult to deviate from.
- Quality and Durability
Achieving this becomes even more complex because the production of every micro coil must not only meet precise specifications but also remain reliable over time.
- Repeatable Performance
The winding and assembly processes must be under tight control in order to ensure similar performance throughout the production batches.
Unique Coil Winding Solutions
How these challenges can be overcome?
- Micro Coil Winding Mastery
They have robotic or automated equipment which can conduct highly precise and repeatable coil winding at very small scales-with the capability to meet industrial demands down to tight tolerances
- Thermo-Pressure Bonding Innovation
They substitute solder with an ultrafine, specialized thermo‑pressure bonding technology to join ultrafine wires-producing solder‑free joints that are oxidation resistant, conductive, and durable, with tight tolerances
Conclusion
Overall, bifilar and trifilar coil windings provide specialised current configurations and either minimal inductance or neutral inductance, making them extremely useful in applications such as Ethernet line magnetics, ferrite suppression, and precision resistive components.
But at the micro‑scale size, however, these present a set of challenges: cost discussions lead to safety, and high-quality mass production; ultra-fine margins; long-term reliability; and coping with extra complexity brought with multiple conductors.
