USB-C buck-boost battery charger is versatile for mobile computing

Believed to be the industry’s first USB-C buck-boost battery charger to support both narrow voltage direct charging (NVDC) and hybrid power buck-boost (HPBB) charging for notebooks, ultrabooks, tablets, and power banks using the reversible USB Type-C connector cable.

The ISL9241 uses firmware control to switch between NVDC and HPBB modes, providing a low-cost and small device that is capable of efficiently processing a full range of power levels. It leverages Renesas’ R3 modulation technology for light-load efficiency and fast transient response to extend the battery run time. The charger’s reconfigurable internal registers allow the use of a smaller inductor for HPBB mode to achieve higher efficiencies across multiple power levels, adds Renesas.

The ISL9241 delivers charging, system bus regulation, and protection features using NFETs for efficiency and bill of material (BoM) cost optimisation. The charger can operate with only a battery, only an adapter, or both connected. It takes DC input power from conventional adapters, travel adapters, and USB Type-C power delivery (PD) ports, and safely charges battery packs with up to four-cell Li-ion series batteries. In NVDC mode, the ISL9241 automatically selects the adapter or battery as the source for system power. NVDC operation also supports turbo mode by turning on the BGATE FET to limit adapter current at the adapter’s current limit set point. The ISL9241’s initial start up state is NVDC, before the system controller’s firmware changes the configuration to HPBB. In higher power HPBB mode, the ISL9241 supports bypass, bypass plus charging, reverse turbo-boost mode, and reverse turbo-boost mode plus charging.

The charger provides 5.0 to 20V reverse buck, boost, or buck-boost operation to the adapter port (OTG mode). This allows configurations to support USB-C PD output for fast charging programmable power supply (PPS) ports. Direct charging the battery can also be enabled by bypassing the ISL9241 in PPS mode.

The reconfigurable charging architecture allows designers to use the charger for multi-port configurations while remaining compliant with the USB PD3.0 standard. Digital telemetry, fault monitoring and protection features are provided and there is also a supplemental power mode that allows the input bias capacitor to store energy and release it during high power demand.

The ISL9241 can be combined with the ISL95338 buck-boost voltage regulator, R9A02G011 USB PD controller or R9J02G012 USB PD controller, and RAJ240045 fuel gauge IC for a complete USB-C PD3.0 and battery charger.

The ISL9241 USB-C combo buck-boost battery charger is available now in a 4.0 x 4.0mm, 32-lead TQFN package.

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