NCP81599 4-Switch Buck Boost Controller onsemi NCP81599 4-Switch Buck-Boost Controller is a USB Power Delivery (PD) controller that converts the battery or adapter voltage into power supply rails. The buck-boost controller operates seamlessly when transitioning between a buck-to-boost or boost-to-buck operation. onsemi NCP81599 controller is capable of operating at a 100% duty cycle. The NCP81599 controller drives four external NMOS switches that allow for the external selection of MOSFETs to optimize the trade-offs between size, cost, and performance. This controller comes with internal drivers capable of driving MOSFETs to meet the 100W requirement. Typical applications include consumer, computing, point-of-sale (PoS), USB Type-C™, and USB PD.