Linear Technology Corporation now joins the wireless battery charging space with the introduction of its LTC4120. This device combines a wireless power receiver with a constant-current/constant-voltage battery charger, functioning as the receive circuit component in a wireless power transfer system; comprised of transmit circuitry, transmit coil, receive coil and receive circuitry.

This device is said to work well with the company’s discrete resonant transmitter reference design or with advanced off-the-shelf transmitters designed and manufactured by PowerbyProxi, a New Zealand-based company in wireless power solutions.   These PowerbyProxi transmitters are claimed to offer advanced features, including 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 percent accuracy, battery preconditioning with half-hour timeout, bad battery fault detection, NTC thermal protection, charge status and a 2-hour safety termination timer.

The new device features dynamic harmonisation control (DHC), which the company advises is a patented technique that enables optimal 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.

Wireless charging with this device is claimed to enable battery powered devices to be recharged without expensive, failure-prone connectors.

Applications include handheld instruments, industrial/military sensors and similar devices in harsh environments, portable medical devices, physically small devices and electrically isolated devices.  LTC4120-based systems offer solutions that are much simpler than those implementing the Qi standard, with additional benefits, including greater transmission distance and no software required.

Linear Technology Corporation

www.linear.com/product/LTC4120