1 Introduction

Redundant power supplies use more than one power-supply unit to provide the necessary power for a load. They help increase a system’s reliability and availability, and ensure system safety in case one of the power-supply units fails. Redundant power supplies are especially important in automotive systems for safety-critical applications, such as automated driving, where a loss of power could result in serious consequences.

ORing and priority power multiplexing are two popular techniques for implementing redundant power supplies in automotive systems. In ORing, the system selects the highest-voltage power source from multiple inputs, while power multiplexing allows the system to switch between different power sources based on priority levels or other criteria. Designers have traditionally used Schottky diodes, P-channel field-effect transistors or a combination of both for redundant circuits in a power supply.

Ideal diode controllers are integrated circuits (ICs) that can control external metal-oxide semiconductor field-effect transistors (MOSFETs) to emulate the behavior of ideal diodes. They offer several advantages over conventional diodes, such as lower power dissipation, higher current capability, reverse polarity protection, reverse current blocking and load dump protection. Ideal diode controllers can also provide inrush current limiting and overvoltage and overcurrent protection.

In this article, we will discuss the concept and benefits of ORing and power multiplexing using ideal diode controllers, the different types and architectures of ORing and power multiplexing circuits, and the challenges and solutions for implementing ORing and power multiplexing using ideal diode controllers in automotive systems.