First USB-C buck-boost regulator replaces two converters

October 11, 2017 // By Nick Flaherty
Intersil, now part of Renesas Electronics, has launched the industry’s first buck-boost voltage regulator for tablets, ultrabooks, power banks, and other mobile devices using the reversible USB Type-C connector.

The ISL95338 bidirectional voltage regulator accepts input power from a wide range of DC power sources such as AC/DC power adapters, USB power delivery (PD3.0) ports, travel adapters and power banks, delivering a regulated voltage up to 24V. The ISL95338 can also convert a wide range of DC power sources to a regulated 20V at its power adapter input. Replacing two separate converters, the single chip provides buck-mode, boost-mode and buck-boost mode and is flexible enough to use in any USB-C power management application.

The chip uses Intersil’s patented R3 modulation technology that extends battery life by combining the best features of fixed-frequency pulse width modulation (PWM) and hysteresis PWM to maximise the power efficiency. The ISL95338 is also USB 3.1-compliant and provides serial communication through SMBus/I 2C, allowing designers to program several input/output current and voltage slew rate settings to create a customized solution.

The ISL95338 is fully compliant to the USB PD3.0 standard and supports programmable power supply (PPS) fast charging with bidirectional 5V to 20V buck, boost or buck-boost modes. Multiple ISL95338 ICs can be combined with the ISL95521A combo battery charger or ISL9238 buck-boost battery charger to enable simultaneous multiport USB-C charging. The ISL95338 can also be used with the R9A02G011 USB PD controller and RAJ240045 fuel gauge IC for a complete USB-C power delivery solution.

In forward mode, input voltage range is 3.8V to 24V and output voltage is up to 20V with no dead zone, with up to 1MHz switching frequency, and automatically reduces switching frequency with no audible acoustic noise when charger is in DCM mode. It includes a system status alert function, bidirectional internal discharge function and full protection against undervoltage, overvoltage, overcurrent, and overtemperature.

The ISL95338 is available now in a 4mm x 4mm TQFN package and is priced at $3.36 USD in 1k quantities.