Advanced package, core technologies in choke coils | Global Sources
by Vianie Li & Cecile de Veyra
Choke coils are key electronic components, tasked with controlling current by blocking or choking higher-frequency AC while allowing DC and lower-frequency AC to pass through. They are also used in reducing electromagnetic interference (EMI). As such, these passive components are widely employed in power supplies, communications equipment, household appliances and the automotive industry.
Driven by miniaturization, choke coils have trended toward smaller packages ideal for surface-mounting but with a higher requirement on performance in increasingly dense circuits on shrinking PCBs.
In the manufacturing sector for choke coils in China, SMD types are popular with buyers, according to suppliers interviewed by Global Sources. To take advantage of this market, Chinese manufacturers will persist in efforts to boost their selections currently dominated by sizes of 0603, 0805, 1210 and 2012. Through-hole units, however, will continue to be produced to fill certain needs such as prototyping, testing and applications subject to great mechanical stress.
To ensure that choke coils improve further in terms of reliability in handling higher frequencies, Chinese companies are considering the use of cores made of nanocrystalline materials instead of ferrite.
“Nanocrystalline cores offer a design option because these materials combine the high permeability of amorphous materials and the low losses of ferrite materials, thus they are very promising in power electronics,” according to Murray Slovick, editorial director of Intelligent Tech Content Services.
“When compared to ferrite cores, nanocrystalline cores provide a wider operational temperature range and significantly higher impedance at high frequencies,” according to Magnetics, a US-based manufacturer of powder core materials.
Shaanxi FKS Electronic Parts Import & Export Co. Ltd has adopted nanocrystalline cores in its choke coils for power electronics, power line filters and RFI suppression in motors and common mode noise suppression. In addition to being small, these components have a high and stable inductance value and a high rated current. Their frequency range is wide, spanning 1kHz to 300MHz, and operating temperature -40 to 125 C.
Growing market
Choke coils are projected to expand at 7.69 percent CAGR from 2021 to 2030, thanks to rising demand for electric vehicles, according to market research firm Dataintelo. Used in the power supply of electric motors, they will find more application when more charging solutions for EVs are realized. Writing for elektroniknet.de in 2021, Patrik Kalbermatten, a senior manager at major US capacitor technology manufacturer KEMET, included a choke for power factor correction and a normal-mode choke coil in the transmitter side or the charging stand and two common-mode choke coils on the side of the receiver or the car in his outline of the essential blocks of a wireless charging system.
Chinese market research company 168Report forecasts that the common-mode choke coils market will reach $77.44 million by 2026 from $64.52 million in 2020 at 4.7 percent CAGR.
Within China, choke coils have been enjoying steady sales growth and this will be sustained in the coming years, driven by high demand in mobile electronics, EVs and wearable devices.
China-made choke coils
Low- and high-frequency choke coils in SMD and through-hole configurations are widely available from Chinese companies. They come in vertical and horizontal styles with or without a base and shielded or unshielded for consumer electronics, communications, home appliances, automotive and industrial applications.
These passive components have a minimum inductance ranging from 0.2 to 100mH, frequency of 10 to 100kHz, rated current of 0.2 to 20A and operating temperature of -25 to 80 C. They are made using domestically sourced ferrite cores, coils and bases, and comply with relevant safety standards such as CE, RoHS and UL.
There are hundreds of choke coil manufacturers in China, which include industry giants such as Murata, Panasonic, TDK-EPC and Vishay. Most domestic and foreign companies also offer other passive components.
For Chinese suppliers, the category accounts for 30 to 60 percent of total shipments, the bulk of which consists of OEM and ODM orders. The majority of these enterprises allocate up to 80 percent of their output for overseas markets, mainly Europe, North America, the Asia-Pacific region and the Middle East.
Production hubs are found in the provinces of Zhejiang, Jiangsu, Guangdong, Shaanxi and Hubei.
250V, 12A rating
Rated at 250V, 12A, Shaanxi FKS Electronic Parts Import & Export Co. Ltd’s 7448251201 choke coil has 1mH inductance, 9mohm DC resistance and insulation tested at 1,500V. It meets ENEC, RoHS and VDE requirements. An order of at least 100 units is required and has a lead time of three days.
1 to 50A current range
Model CMT1730-150Y5A-01 choke coil from Shanghai Meisongbei Electronics Co. Ltd has 1 to 50A current range and 40 C maximum ambient temperature. For a minimum order of 1,000 units, delivery takes eight days.
Edge-wound
Shenzhen Yamaxi Electronics Co. Ltd’s Yamaxi-G5A2246 edge-wound choke coil has high window utilization, power density and distribution parameter consistency, and enhanced heat dissipation. The minimum order requirement of 5,000 units is for delivery within 45 days.
0.5 to 100mH minimum inductance
The Choke 015 from Xiamen YKM Electronics Co. Ltd has 0.2 to 20A rated current range, 0.5 to 100mH minimum inductance range at 1kHz and -25 to 80 C operating temperature. The 5,000-unit minimum order requirement has a five-day lead time.
