LTC4123 Low-Power Wireless Charger for Hearing Aids

Analog Devices LTC4123 is a low-power wireless receiver and a constant-current/constant-voltage linear charger for NiMH batteries. An external programming resistor sets the charge current up to 25 mA. The temperature compensated charge voltage feature protects the NiMH battery, and prevents overcharging. Wireless charging with the LTC4123 allows products to be charged while sealed within enclosures, and eliminates bulky connectors in space constrained environments. The LTC4123 also makes it possible to charge NiMH batteries used in moving or rotating equipment. The LTC4123 prevents charging of Zinc-air batteries as well as batteries inserted with reverse polarity. The LTC4123 pauses charging if its temperature is too hot or too cold. An internal timer provides time-based charging termination. The 2 mm × 2 mm DFN package and low external component count make the LTC4123 well-suited for hearing aid applications or other low-power portable devices where small solution size is mandatory.

Typical Application