Energy Harvesting

TI unveils transmitter circuit with foreign object detection for Qi wireless charging stations

January 21, 2014

Integrated WPC 1.1-compliant controller cuts component count in half, gives smartphone users greater flexibility to charge from 5-V or 12-V charging stations

DALLAS, TX -- Texas Instruments introduces its next-generation wireless power transfer circuit with foreign object detection that will allow designers to bring to market 3-coil, 5-V and 12-V A6 charging stations compliant with the Wireless Power Consortium (WPC) 1.1 specification. The bq500412 controller, which is shipping in volume production, requires half the components compared to other solutions.

Giving smartphone users an improved charging experience, the bq500412 integrates all functions required to control wireless power delivery from the charging station to a receiver circuit used in a Qi-enabled smartphone or other device. In addition to 12-V charging pads, the circuit can be combined with a boost converter to create a 3-coil, 5-V USB charging pad, while taking advantage of a Dynamic Power Limit™ feature to ensure quality operation independent of the power capability of the port. The bq500412 also supports an enhanced foreign object detection scheme, which makes it easier for designers to implement the requirements of the WPC 1.1 specification.

Features and benefits of bq500412:

• Complete WPC 1.1 Qi-compliant design for 12-V, A6 charging stations with a minimum 70-mm by 20-mm: bq500412 needs minimal components, including a CSD97374 power stage integrated circuit.
• Foreign object detection, as mandated by the WPC 1.1 specification, comes standard on the controller, which features an improved algorithm with greater accuracy of error sensing.
• Intelligent power delivery: TI's Dynamic Power Limit technology allows the transmitter to work from either a USB port or low-power adapter.

TI and wireless power

TI's wireless power management products and support fuel design engineers' imaginations to develop innovative, efficient wireless charging capabilities for smartphones, tablets and other portable electronics, and design wireless power charging transmitters ranging from stand-alone charging pads to those embedded in cars and furniture. The company is the leading developer of power integrated circuits that support WPC's Qi standard. TI also is a member of the Alliance for Wireless Power (A4WP) and Power Matters Alliance (PMA).

Availability and pricing

The new bq500412 wireless power transmitter, which is available in volume production through TI and its worldwide network of authorized distributors, comes in a 48-pin, 7-mm by 7-mm QFN package with a suggested resale price of US$2.93 each in 1,000-unit quantities.

To order samples and a development kit, visit:

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