STMicroelectronics' 70W chipsets boost wireless-charging speed

STMicroelectronics’ STWLC98 integrated and wireless power receiver delivers faster wireless charging and flexible charge sharing for diverse portable and mobile devices for home, office, industry, healthcare, and in-car applications. When combined with the STWBC2-HP transmitter IC, the complete transmitter-receiver system can deliver up to 70W on the receiver end at high system efficiency.

The STWLC98 can fully charge today’s high-end smartphones, which contain high-capacity batteries, in just under 30 minutes. In addition, the new device extends opportunities for ultra-fast and convenient charging, free of cables, sockets, and restrictive connections, to a host of new applications and contexts.

Moreover, contactless charging lets product creators simplify enclosure designs, reducing cost and complexity while encouraging new slimline styles and eliminating problems associated with the socket such as contamination.

Compliant with the Qi EPP 1.3 wireless-charging standard commonly used in the smartphone industry, the STWLC98 is managed by a 32-bit Arm Cortex-M3 core that supports a range of features including built-in protection. It also comes with an embedded OS that simplifies Qi 1.3 standalone certification.

On the transmitter side, the STWBC2-HP can work with ST’s STSAFE-A110 secure element to store official Qi Certificates and provides authentication that leverages state-of-the-art cryptography. Support for the company’s innovative ST Super-Charge (STSC) protocol enables fast charging up to the maximum power-transfer rate of 70W.

The STWLC98 features ST’s proprietary adaptive rectifier configuration mode that enhances the ping-up and power transfer spatial freedom of the system in both horizontal and vertical directions without any change in hardware or coil optimization. Enabling ARC mode, which transforms the whole surface of the transmitter as usable charging area, increases the ping-up distance by up to 50 percent in all directions.

The STWLC98 works directly with the STWBC2-HP, which contains a USB-PD interface, digital buck/boost DC/DC converter, full-bridge inverter, three half-bridge drivers, and voltage, current, and phase sensors. Controlled by a Cortex-M0+ core, the STWBC2-HP executes a patented fast PID loop and also supports the STSC protocol.

ST’s new 70W wireless-charging chipset creates a scalable solution that can be deployed in devices like smartphones, tablets, laptops, power banks, True Wireless Stereo (TWS) devices, Bluetooth speakers, and AR/VR headsets.

Designers can also extend fast and convenient wireless-charging to medical equipment like monitors and medicine pumps, as well as cordless power tools, mobile robots, drones, and e-bikes. The chipset is also suited to automotive applications including in-cabin charging solutions and wireless charging of various modules on-board the vehicle.

With built-in power management, the STWLC98 has an energy-saving ultra-low-power standby mode while total end-to-end charging system efficiency can exceed 90 percent, thereby complying with stringent eco-design targets. The power charger chip features dedicated hardware and advanced algorithms that were developed to address challenges in ASK and FSK communication during high power delivery.

Additional safety features include foreign object detection (FOD), which leverages high-accuracy current-sense IP, Q-factor detection, and robust communication between transmitter and receiver. The STWLC98 can also operate in high-efficiency transmitter mode to allow high-power charge sharing between devices. This is coupled with the STWLC98’s industry-first embedded Q-factor detection in a receiver device to ensure safe operation in transmitter mode.

Users of ST’s wireless power solutions can download and benefit from the free PC-based graphical tool, ST Wireless Power Studio, to accelerate design-in and simplify processes including calibrating FOD, tuning Q-factor detection, and communication diagnostics.