Wireless Li-Ion Charger with 1.2V Step-Down DC/DC Converter

The LTC4126-ADJ is a low-power wireless single-cell Li-Ion battery charger with an integrated step-down DC/DC regulator. The step-down regulator is a low-noise multimode charge pump which is powered from the battery and provides a regulated 1.2V at the output. The switching frequency is set to either 50kHz or 75kHz depending on the mode to keep any switching noise out of the audible range.

The constant-current constant-voltage Li-Ion battery charger has automatic recharge, automatic termination by safety timer, and battery temperature monitoring via an NTC pin. Charge current is programmable from 1mA to 50mA via an external resistor. Undervoltage protection disconnects the battery from all loads when the battery voltage is below 3.0V.

The small package and minimal external component count make the LTC4126-ADJ and its variants suitable for hearing aid applications and other low power portable devices. See the chart in the data sheet.

APPLICATIONS

* Hearing Aids

* Low Power Li-Ion Powered Devices

* Wireless Headsets

* IoT Wearables

* Wireless Li-Ion Battery Charger Plus High Efficiency Multi-Mode Charge Pump DC/DC

* Programmable Charge Current from 1mA to 50mA Via an External Resistor

* Wideband Rx Frequency: DC to >10MHz

* Integrated Rectifier with Overvoltage Limit

* Charge Voltage: 4.2V

* Low Battery Disconnect: 3.0V