Compact chargers for IoT and wearable devices can be reduced in size, using the STEval-ISB045V1 wireless battery-charger development kit, says the company. It lets users quickly build compact chargers, up to 2.5W, with a space-saving 20mm-diameter coil, for charging small smartwatches, sports gear, or healthcare equipment.

It is built around the STWBC-WA wireless charging-transmitter controller and comprises a charging base unit containing a transmitter board with the 20mm coil connected and ready to use. The PC-based STSW-STWBCGUI software configures the STWBC-WA and monitors runtime information such as power delivered, bridge frequency, demodulation quality, and protocol status. The kit includes a dongle for running the graphic user interface (GUI).

A supporting ecosystem includes certified reference boards, software, and documentation to help developers quickly deliver the smallest and best-performing chargers into fast-growing new markets for smart objects and wearables, claims ST Microelectronics.

The STWBC-WA controller chip contains integrated drivers and natively supports full-bridge or half-bridge topologies for powering the antenna. The half-bridge option allows charging up to 1W with a smaller-diameter coil for an even more compact form factor. The chip supports all standard wireless charging features, including foreign object detection (FOD) and active presence detection for safe charging. It uses digital feedback to adapt the transmitted power for optimum efficiency at all load conditions. Two firmware options give users the choice of a fast turnkey solution or customising the application using application processor interfaces (APIs) to access on-chip peripherals including an ADC, a UART, and general purpose input/outputs (GPIOs).

The STEVAL-ISB045V1 kit is available now. The STWBC-WA transmitter controller ICs are in production in a VFQFPN32 package.

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