Industry White Paper

MOSFET Selection for Reverse Polarity Protection

December 02, 2022 by onsemi
Topics Covered
  • ISO Pulses
  • Reverse Polarity Protection Techniques
  • MOSFET Selection
  • Ideal Diode Application
  • Test Setup

Application Note Overview 

Reverse polarity protection (RPP) is a crucial building block for any battery connected electronic control units (ECU) required by all automotive vehicle manufacturers. This application note first gives an overview of ISO pulses that are commonly used to replicate the voltage transients in real applications. Then it details several potential RPP techniques, including diodes, P−Channel and N−Channel MOSFETs, before guiding the readers to select an external N−Channel MOSFET, that will provide RPP and help reduce the power losses of the system.