Batteries provide power to many different applications across a wide range of industries. Wireless charging enables those applications where it is difficult or impossible to use a connector. Examples include products that need to operate in harsh environments or need to be cleaned or sterilized as well as products that are simply too small for a connector. In this video, we will show the LTC4120 400mA wireless power receiver buck battery charger. This device works with a wireless power transmitter to charge a 3.5V to 11V battery with a constant-current/constant-voltage charge algorithm. The LTC4120 was developed with technology partner PowerbyProxi and integrates PowerbyProxi’s patented Dynamic Harmonization Control (DHC) technique. This technique enables high efficiency charging without any of the thermal or overvoltage problems typical of wireless power systems. With the system shown, up to 2W can be transmitted at a distance of up to 1.2cm. The LTC4120’s adjustable 3.5V to 11V output accommodate several types of batteries including 1-cell and 2-cell Li-ion batteries. 50mA to 400mA charge current is programmed with a single resistor. The LTC4120 includes a safety termination timer eliminating the need for a microprocessor.