How to Select the Right Front-End Buck Converter for Your Automotive ECU

By: Reno Rossetti

Abstract: Internal combustion engine (ICE) vehicles rely on a lead-acid battery to supply their numerous electronic control units (ECUs) required by the introduction of advanced driver assistance systems (ADAS). Depending on system complexity, these loads require from a few amperes to tens of amperes of current. In this application note, we review different levels of complexity for an automotive ECU power management system. For a low level of complexity, a monolithic front-end buck converter is the best solution for efficiency and PCB size. For medium levels of complexity, a PWM controller, in conjunction with external MOSFETs, is the best approach. Finally, for higher level of power, a two-phase interleaved approach yields the best results in terms of efficiency and size.