Basic Facts about Inductors [Lesson 3] Roles of Inductors 2 -Power Inductors-

May 30, 2011
Category: Inductor Room

Inductors have many different applications, and a variety of product types are available to choose from, to suit the application.
The previous column explained inductors for high-frequency circuits. This column explains inductors for power supply circuits.
Typical applications for inductors used in power supply circuits are "voltage conversion" and "choke," and these inductors are used in a wide range of electronic equipment.

　　　　Table １　Applications and roles of inductors for power supply circuits

Application	Role			Required characteristics
Voltage conversion	Accumulation and discharge of DC energy			Low DC resistance, ow AC resistance, good DC superposition characteristics
Choke	Cutting high-frequency AC current components			High inductance, low DC resistance

Murata Manufacturing's lineup of inductors for power supply circuits includes products with two different structures: winding and monolithic. The features of each type are introduced briefly below.

 

◆Features of winding inductors
Winding inductors have copper wire wrapped in a spiral shape around a ferrite core. In addition, most of Murata Manufacturing's winding inductors for power supply circuits coat the copper wires wrapped around the ferrite core with resin. This resin coating is used for purposes such as to increase the product strength and to form a simple closed magnetic path.

Winding products have various merits when used in the large current range and high inductance range. The target markets span a wide range from mobile phones to TVs, HDD, and digital cameras.
Applicable Murata Manufacturing products：
LQH-P and LQH2MC series (for voltage conversion)

LQH31C/32C/43C/55D/66S series, LQW18C series (for choke)

◆Features of monolithic inductors
Multilayer inductors are integrated monolithic-type inductors that layer ceramic materials and a coil conductor.

The monolithic structure enables a smaller size, lower profile, and lower cost compared to the winding structure. The main market for monolithic inductors for voltage conversion is mobile phones, and demand is expected to increase further as switching frequencies become higher.
　Applicable Murata Manufacturing products：
LQM-P series (for voltage conversion)

LQM-F series (for choke)

As described above, inductors for power supply circuits are used for various markets and applications according to their features. The next issue will introduce differences in applications and features according to inductor structures.

person in charge: Murata Manufacturing Co., Ltd. K.M

May 30, 2011
Category: Inductor Room