ALL-IN-ONE WIRELESS POWER CHIP FROM LINEAR

Linear Technology has for the first time combined a wireless power receiver with a constant-current/constant-voltage battery charger, to operate as a complete wireless power transfer system comprised of transmit circuitry, transmit coil, receive coil and receive circuitry.

The LTC4120  has been designed to work with the supplier’s discrete resonant transmitter reference design or to work with off-the-shelf transmitters from Power by Proxi, a New Zealand-based wireless power firm.

Power by Proxi transmitters support simultaneous charging of multiple receivers with a single transmitter and foreign object detection to prevent excessive heating during transmit faults.

The LTC4120 accepts a rectified 4.2V to 40V input from the receive coil to power a full-featured constant-current/constant-voltage 400mA battery charger that includes programmable charge current, a programmable 3.5V to 11V battery float voltage with ±1% accuracy, battery preconditioning with half-hour timeout, bad battery fault detection, NTC thermal protection, charge status and a 2-hour safety termination timer.

A technique known as dynamic harmonization control (DHC) is designed to optimise wireless power transfer across a variety of conditions while providing thermal management and overvoltage protection.

“This technique modulates the resonant frequency of the receiver tank to provide lossless adjustment of the power received as well as the power transmitted to enable an efficient and robust solution for wirelessly charging battery-powered devices,” said Linear.

“The LTC4120 is the first result of an ongoing partnership between Linear Technology and PowerbyProxi, a technology company focused on providing real world wireless power solutions to the market,” said Don Paulus, general manager of Linear Technology’s power products group.

The LTC4120 is available in a low profile (0.75mm) 16-pin 3mm x 3mm QFN package with backside metal pad for excellent thermal performance.