The SSP4090 is a 5V-input, 1.5A-max boost-mode charge management IC for 2-cell Li-ion battery packs in series. SSP4090 integrates a power MOSFET in an asynchronous switching topology requiring very few external components, shrinking solution size and BOM cost. The boost switching charger operates at 500kHz with up to 90% conversion efficiency. Four feedback loops govern the charge cycle: constant-current (CC), constant-voltage (CV), die-temperature regulation, and an adaptive input-current loop that prevents adapter collapse and works with any adapter. SSP4090 integrates a 24V OVP function, so the input port safely tolerates up to 24V transients and charging is disabled above 6V input, making it ideal for USB-powered applications.