The FAN54005 from onsemi is a USB-Compliant Single Cell Li-ion Switching Charger that has been designed to be configurable for 200 mA to 1.45 A systems using a single external resistor. It requires an input voltage of 4 - 6 V. This BMIC consists of a Pulse Width Modulation (PWM) modulator, reference voltage detector, DAC converter, logic and control circuits, charge pump, voltage regulator, integrated MOSFETs, and protection circuits. It can charge a battery in three different phases – conditioning, constant current, and constant voltage and uses an I²C interface to send commands at a data rate of 3.4 Mbps to modify charging parameters and operating modes when required. This charger IC includes a host processor integrated to the I²C interface to change the current threshold, thereby ensuring USB compliance and minimizing charging time.

The FAN54005 automatically restarts the charging cycle when the battery charge falls below a certain threshold and provides the status of charge to the host processor through the I²C port. The switching charger enters a high-impedance mode when the input source is removed, preventing charge leakage from the battery to the input. It reduces the charge current when the die temperature reaches 120 degrees C, thus protecting both the device and PCB from over-heating-related damages. The BMIC can also operate as a boost regulator to limit the in-rush current from the battery. It is available in a wafer-level package that measures 1.96 x 1.87 mm and is ideal for E-Cigs, vapes, toys, drones, digital cameras, cell phones, gaming devices, wireless speakers, headphones, and IoT applications.