Wireless battery charger IC operates across a 1.2-cm air gap

The LTC4120 combines a wireless power receiver with a constant-current/constant-voltage battery charger. It functions as the receive circuit component in a complete wireless power transfer system comprised of transmit circuitry, transmit coil, receive coil and receive circuitry. It enables battery powered devices to be recharged without connectors.

The wireless battery charger works with a discrete resonant transmitter reference design or with advanced off-the-shelf transmitters, such as the device from PowerbyProxi. The unit accepts a rectified 4.2 to 40-V input from the receive coil to power a CC/CV 400-mA battery charger that includes programmable charge current, a programmable 3.5 to 11-V battery float voltage with ±1% accuracy, battery preconditioning with half-hour timeout, bad-battery fault detection, NTC thermal protection, charge status, and a two-hour safety termination timer.