The ISL9241 from Renesas is a Digitally-Configurable Buck-Boost Battery Charger that has been designed to safely charge battery packs with up to 4-series Li-ion batteries via a USB type-C interface. It requires an input voltage of 3.9-23.4 V (no dead zone) and provides an output voltage of 3.9-18.304 V. This battery charger offers charging functionality, system bus regulation, and protection features with only N-FET transistors. It takes input power from a wide variety of DC power sources (conventional AC/DC charger adapters, USB type-C power ports, and travel adapters) and uses Renesas’ R3 technology to provide a high, light-load, and efficient charging mechanism. This charger supports both narrow voltage direct charging (NVDC) and hybrid power buck-boost (HPBB/bypass) charging modes and can switch between these two modes using firmware control. 

This buck-boost battery charger includes reconfigurable internal registers that allow the use of a smaller inductor for the HPBB mode to achieve higher efficiencies across multiple power levels. It also has system power monitor (PSYS) functionality, which provides an analog signal representing total platform power to cater to Intel IMVP-compliant systems. The PSYS output integrated into this charger connects to a wide range of IMVP core regulators to provide an IMVP-compliant power domain function. It uses SMBus or I2C serial interfaces to control several key parameters and deliver a customized solution. This charger is available in a surface-mount package that measures 4 x 4 mm and is ideal for 2- to 4-cell tablets, notebooks, power banks, and other battery-powered portable applications.