Multi-gap ferrite cores
Lower losses due to distributed air gaps in ferrite cores
Quality
Today's electronics applications always require high quality in all areas. This quality must be based on reliable components.
Extensive program
We offer an extensive range of high-quality and reliable ferrite components.
Many years of experience
With more than 40 years of experience, we supply customers from a wide range of industries worldwide.
Ferrite materials
We offer our extensive range of ferrite cores in the materials BFM8 and BFM9 as well as in the high-permeability materials BFM2k, BFM3k, BFM6k BFM10k and BFM11k.
Multi-gap ferrite cores from Blinzinger Elektronik
Distributed air-gap ferrites offer reduced core losses, a more homogeneous field distribution, better thermal distribution, and improved inductance linearity.
To adjust inductance, reduce losses, and prevent magnetic saturation of the material, air gaps are inserted into ferrite cores. Air gaps improve the linearity of the core, allowing it to be used at higher currents without an uncontrolled increase in the magnetic field.
The magnetic characteristics of cores can be adjusted by a single air gap or by distributing air gaps—also known as multigap, multi-air gap, or distributed gap—for a wide variety of applications, such as chokes or voltage converters.
Air gap variants:
- Single Gap: A single air gap placed in the center of the core (center slug) to control the AL value (inductance) and prevent saturation. However, large air gaps increase the stray magnetic fields, causing additional losses in the copper at high frequencies.
- Distributed air gaps (multi-gap): In this variant, the air gaps are distributed multiple times across the core. This reduces stray magnetic fields and minimizes losses in the copper, which is particularly advantageous at high frequencies. Multi air gaps can be inserted in both the center slug and the outer limbs (e.g., in U or URR cores), which greatly optimizes the emission of the magnetic field into the component depending on the application.
Ferrite cores with distributed air gaps (multi-gaps) offer targeted optimization of magnetic characteristics by distributing several small air gaps instead of a single central gap. This technique reduces saturation effects and significantly improves thermal and magnetic properties.
The placement of several small air gaps in the core material results in a more uniform magnetic field distribution, which minimizes temperature hotspots and improves the effective use of the ferrite material. Uniform distribution of losses reduces local heating and enables better heat dissipation across the entire core volume.
Distributed air gaps lower local flux densities, thus reducing losses due to hysteresis and eddy currents – especially at higher frequencies.
The inductance of cores with distributed air gaps exhibits improved linearity compared to single-gap cores, which improves control performance in power electronic circuits (e.g., PFC chokes, RF chokes, LLC converters).
The main advantages of cores with multi-gap technology are:
- Reduced losses
- Reduced leakage flux
- Significantly increased power density
- Better thermal behavior (higher temperature stability)
We manufacture multi-gap ferrite cores not only in standard versions, but also offer these cores according to customer requirements.
The following multi-gap cores are available with distributed air gaps: E, ETD, ER, PM, PQ, RM, U and URR.
Ferrite cores with distributed air gaps are available in our BFM8, BFM9 and BFM95 power materials.
In addition to these common standard designs, we also offer multi air gaps in customized ferrite core and AL-Value versions.
In summary, the main reasons for air gaps in cores are:
- Influence on inductance (AL value): The size of the air gap directly influences the inductance value of the core. Increasing the gap reduces the inductance, allowing tuning to the desired performance.
- Reduction of losses: By limiting the magnetic flux, hysteresis losses are reduced.
- Limitation of saturation: An air gap in the core is intended to prevent the ferrite core from losing its ability to store magnetic energy at high magnetic fields.
- Increased linearity: An air gap in the core results in a flatter and more linear hysteresis curve, which improves the application of power electronic components such as chokes.
- Energy storage: An air gap is an area for storing magnetic energy, which is very important for energy storage applications such as chokes.
Ferrites with a distributed air gap can be used to achieve tailored magnetic properties for a wide variety of applications.
