Simplified Mode Design of Micro Inductors 3

In the optimal design mentioned above, the distributed power loss between the magnetic core and winding is Pcoreloss/Pwind1oss=2/3. Generally speaking, as long as hysteresis loss is ignored and the magnetic core stack is thin enough to match the penetration depth, and the inductance requirement can be met by adjusting the magnetic permeability, all optimized designs of the planar inductor and transformer constructed in Figure 1 will maintain this ratio.diode

4 Inductance adjustment

One method to meet the requirements of inductance is to adjust the magnetic permeability of the core, which creates a favorable magnetic field structure and avoids inductance suppression introduced during the optimization process.

To optimize the design and obtain the required inductance, effective magnetic permeability is required

In the equation, σ opt (η) is the current density per unit conductor width at an efficiency of η. For an optimized design, once the efficiency η is selected, the magnetic permeability μ r is fully specified.

For example, assuming the parameters in Table 1 ignore the end turns and other 'invalid' spacing, and are designed within the range of 95.5%<η<98.5%, the relative magnetic permeability values may be in the range of 100<μ r<400, as shown in Figure 3. For a certain efficiency, the actual design generally requires a higher magnetic permeability than shown in Figure 3, because the distance between the magnetic core and the insulation turns is ignored in the simplified mode analysis, thus increasing the length of the magnetic circuitdiode