Inductors for Power Lines

Introducing the feature of Murata inductors for power lines and applications.
The typical applications of inductors used in power circuits are for "power inductors" and "chokes", and are used in all electronic equipment.


Table 1: Application and Role of Inductors for Power Circuits
  Applications Purpose
Power Inductor Accumulates and discharges electrical energy as magnetic energy, and consists of part of the voltage conversion circuit. Low DC resistance, low AC resistance, effective DC superimposing characteristics
Choke Inductors Cuts high frequency AC current components High inductance, low DC resistance

Murata's lineup of inductors for power supply circuits includes products with two different structures, wire wound and multilayer.
These products can be used for various applications utilizing the features of each product.


SubTitleIcon6    Murata's Technology

1. Manufacturing Technology

  Wire Wound Method Multilayer Method
Structure Structure Wire Wound Method Structure Multilayer Method
Features
  • Lineup of various sizes
  • Can be used for high inductance values in mH order
  • Demonstrates advantages in small low profile areas


2. Wire Wound Inductor Technology

The combination of Murata's magnetic material technology and wire wound technology (applicable to various wire diameters) realized a lineup of various variations.

  • Wire wound technology and terminal processing technology can be used for thin wires to thick wires
  • Magnetic circuit design technology, ferrite material technology and processing technology which enables the manufacturing of ferrite cores excellent in DC superimposing characteristics
  • Magnetic resin material technology and processing technology which contributes to improvement in the inductance acquisition efficiency

Wire Wound Inductor Product Cross Section Image
Wire Wound Inductor Product Cross Section Image


3. Multilayer Inductor Technology

The combination of Murata's magnetic material technology and multilayer technology realized large current characteristics even in small size areas.
  • Internal circuit forming technology and ferrite core material technology which enables low AC resistance in the high frequency range
  • Internal power forming technology with high aspect ratios which enable low DC resistance
    Note: Aspect ratio (T/W) : Ratio of thickness (T) to the width (W) of the inductor conductor

Multilayer Inductor Chip Cross Section Image
Multilayer Inductor Chip Cross Section Image


SubTitleIcon6    Difference in Characteristics by each Structure

1. Features of Wound Structure

The wire wound inductor consists of a copper wire spirally wound around the ferrite core. Most of Murata's wire wound inductors for power circuits, are coated with various resins over the copper wire wound around the ferrite core. The purpose of the coating resin is to improve the strength of the product.
The merits of using a wire wound product are demonstrated when used in large current areas and high inductance areas. The applicable markets vary from mobile phones to TV and digital cameras. 

Applicable Murata products
for power inductors
LQH_P Series/LQH2MC_02/LQH2MC_52 Series
for chokes
LQH31C/LQH32CN_23/LQH32CN_33/LQH32CN_53/
LQH43CN_03/LQH43CN_33/LQH55D/LQH66S Series
for chokes
LQW15CN_00/LQW15CN_10/LQW18C Series
Structure Wire Wound Method

1. Features of Wound Structure


2. Feature of Film Structure

The multilayer inductor consists of a sintered alternately layered ceramic material and coil conductor. Compared with the wound structure, small sizes/low profiles are possible.
Along with the progression of the high frequency of switching frequencies, the required inductance of the multilayer inductor for power inductors where mobile phones are the main market tends to be deteriorating, and cases where the multilayer inductor can be applied are expected to increase further.

Applicable Murata products
LQM_P Series (for power inductors) 
LQM_F Series (for chokes)
Structure Multilayer Method

2. Feature of Film Structure

3. Summary

  Wire Wound Method Multilayer Method
Structure Structure Wire Wound Method Structure Multilayer Method
Features
  • Lineup of various sizes
  • Can be used for high inductance values, and is ideal for power supply booster circuits
  • Ideal for small size/low profile areas
  • Magnetic shielded structure
Applications Mobile phones, digital cameras, TV, HDD, game machines Mobile phones, digital cameras


SubTitleIcon6    Effective use of Inductors

The product group of Murata's inductors for power circuits consists of the wire wound type and the multilayer type. For the applications of power inductors, Murata has prepared the "Murata Power Inductor Selection Tool" which can calculate and display the performance of inductors based on actual use conditions.
The application of power inductors greatly contributes to the loss of inductors in the conversion efficiency of a set.
The loss of inductors can also be estimated in the frequency and current values actually used, by using the "Murata Power Inductor Selection Tool". The inductors mounted in sets which increase the conversion efficiency of a power supply to the maximum can easily be selected.