The ISL78224 is a 4-phase, bidirectional, synchronous PWM controller designed to perform power conversion between 12V and 48V buses up to 3kW at >95% conversion efficiency. One ISL78224 supports both Buck and Boost power conversion, enabling a compact and robust design with minimum components. The ISL78224 regulates both voltage and current to control power transfer from bus to bus. The multiphase architecture uses interleaved timing to support up to four parallel power stages per ISL78224. By interleaving the power stages, the ripple frequency is multiplied, reducing input and output ripple voltage and current. Lower ripple results in fewer input/output capacitors and therefore lower component cost and smaller circuit implementation. The IC is designed to be interleaved in a master/slave architecture to be scalable for higher power. Integrated within the device is a dual-output Flyback controller that generates both a 12V supply for the power stage FET drivers and a 6V supply for the ISL78224 from either of the two buses. A 200mA auxiliary linear regulator supplies a local microcontroller or interface devices. A PMBus interface provides system control and diagnostics to support functional safety requirements. This digital interface offers the system controller the ability to program operating modes, voltage and current limit warning and protection thresholds, individual fault response, and rapid fault condition detection.