Wireless charging controller is WPC 1.1-compliant, enables Qi developments

September 12, 2013 // By Paul Buckley
Texas Instruments has introduced the company's next-generation wireless power transfer circuit to support the WirelessPower Consortium (WPC) 1.1 specification.

The bq500212A transmitte requires one-third fewer components than competitive solutions. The circuit allows designers to impllement Qi-compliant wireless charge pads or stations that can operate from a USB port or 5-V power adapter.
When more Qi charging stations become available, users of Qi-enabled smartphones, smartwatches and many other 'enclosed' portable consumer electronics will be able to keep their batteries charged longer. Products like the Kickstarter-born AGENT Smartwatch are using TI’s bqTESLA wireless power products, including the bq500212A and a bq51050B receiver, to ensure wireless power capability.
“AGENT Smartwatches need to be water resistant, and consumers shouldn’t need to worry about plugging their watches into a charging adapter day after day,” said Chris Walker, founder of Secret Labs. “TI’s wireless power products give our customers the ability to simply set their AGENT Smartwatch on the included Qi charging pad (or any other Qi-compliant charging pad) from time to time to keep the battery topped off.”

The bq500212A needs five components, including two new CSD97376 Power Stage integrated circuits; while other products may require up to 15 devices.
TI’s Dynamic Power Limit technology enables the transmitter to work from either a USB port or low-power adapter. The device’s standby mode ensures <100 mW of standby power with no receiver on the pad and <50 mW once the receiver has finished charging.
The hybrid capacitor scheme reduces system bill of materials cost by using a combination of X7R and COG capacitors instead of only relying on COG capacitors.
Foreign Object Detection, as mandated by the WPC1.1 specification, comes standard on the bq500212A, which features an improved algorithm with greater accuracy of error sensing.
TI’s bq5101x integrated receivers provide a regulated DC output and digital-control feedback to the transmitter, while TI’s bq500xx family of wireless power transmitters efficiently manages the power transfer to the receiver.   
The bq500212A wireless power transmitter comes in a 48-pin, 7 by 7-mm QFN package for $2.78 (1,000).