Tech Library
Product Overview
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The power inductor BCL series for automotive is compact inductors with high inductance by using TDK’s proprietary material technology and structural design.
The use of metallic magnetic core material allows for higher currents than ferrite-based products and a wider operating temperature range, making them suitable for automotives with very high temperature environment.
In this article, we will clearly explain some useful information about the BCL series including its structure, features, and applications.

Product Overview

Figure 1 shows an overview of the BCL Series.

Figure 1: Product Overview
Series BCL Series
Product Overview

Wire wound power inductors using metallic magnetic core material.
TDK’s proprietary material and molding technologies enable low-pressure molding, thus achieving high inductance using thin wires. Also, since they are made with metallic magnetic core material, these inductors can withstand higher currents compared to ferrite inductors.
Its compact size enables high-density mounting.

Features ・Compact and high inductance
・Low leakage flux
・High efficiency
・Operating temperature range from -67°F to 311°F (-55°C to 155°C) (including self-temperature rise)
・40V Rated voltage
・AEC-Q200 compliant
Automotive (ADAS, various ECUs)
Automotive Grade

Product Structure

The structure of the BCL series is shown in Figure 2.
The BCL series is an inductor using wire wound method.
The air core coil is molded with a metallic magnetic core material, and the wire pulled out from the bottom is connected to the terminal.

Figure 2: Product Structure

Product Features

The BCL series uses a metallic magnetic core material with excellent DC bias properties, allowing for higher currents compared to ferrite-based products of the same size.

Figure 3: Comparison of DC bias characteristics

Comparison of DC bias Properties

The BCL series has a one-piece construction in which the coil is completely molded with metal material, resulting in lower leakage flux and higher efficiency in the power circuit compared to other TDK series.

Figure 4: Leakage flux

Leakage flux

Figure 5: Power Supply Efficiency

Power Supply Efficiency


An example of the BCL series application is shown in the blue box in Figure 6.
With a guaranteed breakdown voltage of 40V, the BCL series can be used in PMICs for automotive DC/DC converters, such as a step-down circuit for a 12V power supply.
Compared to conventional ferrite inductors, the BCL series is smaller in size, can withstand higher current, and has a higher mounting density.

Figure 6: Applications


Product Details

Click on the links below to view detailed information of the BCL series or to purchase samples.
We are continuously expanding our product lineup to meet our customers' needs for a wide variety of power circuit inductors.

Figure 7: Product Details
  • Automotive Grade
    Automotive Grade
Series Type Application L x W Dimensions Height Inductance Rated Current
Automotive Grade
3.2x2.5mm 1.5mm, 2.0mm 2.2~100μH 0.7~4.31A

What are power inductors?

Power inductors are inductors used for power supply circuit such as DC-DC converters. They are also called power coils or power choke coil. One of the inductors' characteristics is that they store energy by self-induction function. Chopper type DC-DC converters use inductors having such characteristics with switching devices for voltage conversion (see Figure 8).
Depending on the processing method, inductors can be classified into multilayer type, thin-film type, and wire-wound type. Since wire-wound type permits large current to flow, most of the power inductors are wire-wound type. Various wound-type power inductor products with ferrite or soft magnetic metal core are offered. Recently, the multilayer type and thin-film type, with which reduction of size and thickness can be achieved, are being improved to allow for larger current.

Figure 8: DC-DC converter (chopper type / step-down type) and inductor

The voltage is dropped to a desired level in accordance with the duty ratio (the ratio that indicates how long the switch is ON during the switching cycle) setting.