Vishay releases wireless charging Tx and Rx coils with up to 90% humidity resistance and a smaller footprint

October 4, 2024 /SemiMedia/ — Vishay Intertechnology, Inc. recently introduced new powdered iron based wireless charging transmitter (Tx) and receiver (Rx) coils optimized for high humidity conditions up to 90 % RH. Designed for industrial, medical, and consumer electronics applications up to 30 W, the Vishay Dale IWAS3222CZEB190JR1, IWTX4646DCEB240JR1, IWTX47R0DAEB6R3JR1, and IWTX47R0EBEB240JR1 offer high temperature operation to +105 °C in 25 % smaller footprints than previous-generation devices and competing solutions.

The high moisture resistance of the devices released today results from their specialized shield coating, which provides superior environmental protection. In addition, the coils’ high saturation powdered iron makes them immune to the temperature fluctuations and sharp inductance drop-off behavior observed in ferrite-based solutions. Shield material selection is critical, as it is used to boost the inductance of the coil, contain any flux leakage, and maximize flux directivity.

Featuring a self-binding, enameled copper winding, the IWAS3222CZEB190JR1 Rx coil features inductance of 19.6 µH, Q of 28.5 at 200 kHz, and DCR of 357 mΩ. The IWTX4646DCEB240JR1, IWTX47R0DAEB6R3JR1, and IWTX47R0EBEB240JR1 offer inductance from 6.3 µH to 24 µH. With DCR as low as 40 mΩ, Q up to 200, and heat rating current to 7 A, the Tx coils maximize power transfer to the receiver element, while their high saturation currents up to 22 A ensure stable inductance and consistent performance across the operating current range.

For additional durability, the Tx coils feature a silk-covered litz wire that protects against scratching and wire deformation, provides improved insulation, and reduces the electrical skin effect and proximity losses. In addition, the IWTX4646DCEB240JR and IWTX47R0EBEB240JR1 are manufactured with an alpha winding technique that eliminates wire crossover and achieves the lowest profile possible.

Typical applications for the devices will include handheld, battery-powered tools and diagnostic and therapeutic instruments; drones; smartphones and tablets; gaming controllers; and wearable devices. RoHS-compliant, halogen-free, and Vishay Green, the wireless charging coils are available in rectangular, square, and round form factors.