USB 3.1/USB-C and mobile device battery protection

USB-C is becoming the preferred connection method for smartphones, tablets, and many other mobile devices that use lithium-ion batteries due to its data transfer speeds (10Gbps or higher), power capacity (up to 100W), smaller size, and reversible compatibility. At such high data speeds and power capacity, maintaining signal integrity while preventing electrical hazards is increasingly important to provide a great user experience.

USB-C presents unique challenges to designers, including compact designs with 0.5mm pin pitch; USB 3.1 Gen2 at 10 Gbps; USB-PD up to 100 W; risk of sensitivity to uncontrolled overheating contamination; and reports of thermal damage (burning) to cables and devices. Even qualified USB-C cables or devices are at risk of overheating. Common failure modes include: ESD electrostatic discharge from human contact; surges during hot plugging and unplugging; overload current caused by pin bending and cable wear; overheating caused by connector contamination such as lint, water, dirt, and dust. As a result, USB-C plugs are prone to dangerous overheating.

After its introduction in the 1990s, lithium-ion batteries were immediately adopted in consumer and industrial applications due to their high energy density and small size. In order to obtain the longest battery runtime in the thinnest possible form factor, designers are increasingly turning to large surface area, high capacity envelope-shaped lithium polymer (LiP) batteries. In the rapidly growing market, high capacity rechargeable LiP batteries are frequently used in the thinnest mobile electronic devices. At the same time, the holding current of traditional battery protection devices used in battery pack applications for low-end mobile phones is often not high enough to meet the latest design requirements. As a result, manufacturers are facing an increasing challenge to find overtemperature protection devices that are ultra-small but still compatible with the higher holding currents generally required in LiP battery applications.

Littelfuse has deep application expertise to help provide the right product solutions for mobile devices. The following technical white paper will provide you with our latest technology and design, come and download it!

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