The LTC4123 is a wireless charging receiver which has been optimized for low power applications. It combines a 30mW wireless receiver with a constant current/constant voltage linear charger for NiMH batteries, such as Varta's power one ACCU plus series. An external resonant LC tank connected to the chip enables the IC to receive power wirelessly from an alternating magnetic field generated by a transmit coil. Integrated power management circuitry converts the coupled AC current into the DC current required to charge the battery.
The LTC4123 can be used for Wireless charging of a completely sealed product and eliminates the need to constantly replace primary batteries. Air (Zinc Air) detection allows applications to work interchangeably with both rechargeable NiMH batteries and primary Zn Air batteries with the same application circuit. Both battery types can directly power a hearing aid ASIC without the need for additional voltage conversion. By contrast, a 3.7V Li ion battery requires a step down regulator in addition to the LTC4123 functionality to power the ASIC.