Qi Extended Power chip for faster wireless charging

November 12, 2017 //By Graham Prophet
ST Microelectronics’ advanced wireless-charging transmit chip enables faster charging of portable devices through the latest industry standard (Qi Extended Power) and includes detection and safety features, plus lowest standby power, for optimum user experience and efficiency.

ST claims the device as one of the first chips to support the latest industry standard for faster charging. The Wireless Power Consortium (WPC) that manages the Qi specification has introduced the Extended Power profile for faster charging, raising the maximum charging power from 5W to 15W.

 

The STWBC-EP contains a step-up (boost) DC/DC converter and a controller, with the Qi charging algorithms already implemented in firmware to save any need to integrate software and an additional microcontroller in their designs. Together, the converter and controller generate the input power and the control signals for an external half-bridge power stage that drives the charging transmitter antenna. This architecture gives designers flexibility to optimize the external half bridge and its associated gate drivers for use with any supply voltage from 5V to 12V, and to ensure compatibility with USB quick chargers.

 

An evaluation kit, STEVAL-ISB044V1, includes a 15W Qi MP-A10 reference design, 12V 2A AC/DC adapter, a USB/UART dongle for connection to the PC and USB cable, as well as pre-loaded firmware. In addition to the supporting documentation, a graphical PC-based configuration tool is also provided to help customize settings.

 

STWBC-EP uses 16 mW in standby and is able to wirelessly transfer more than 80% of the total input power, with added features created by ST that include a solution enhancing active presence detection to wake the system quickly when a compatible object is presented for charging. The technology also enhances the performance of Foreign Object Detection (FOD), to cut power and prevent overheating if objects containing metals are brought too close to the charger. Other innovations enhance power control and energy transfer to maximize efficiency and ease of use.

 

ST also has a 15W receiver chip (STWLC33) for use in high-speed chargeable devices, which developers can use to complete their applications.

 

In a 32-lead QFN (5 x 5 mm) package it is priced from $3.175