SDAA218 November   2025 DRV8363-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Power Loss and Thermals in Motor Driver Systems
    1. 2.1 Conduction Losses
    2. 2.2 Switching Losses
      1. 2.2.1 Effect of Switching Frequency
  6. 3Real World Motor Driver Limitation
    1. 3.1 Electro-Magnetic Interference (EMI) – System Noise Considerations
    2. 3.2 Motor Driver Voltage Tolerance
  7. 4Summary
  8. 5References

1 Introduction

BLDC motors have a variety of functions throughout multiple automotive systems. Traditionally, the most common voltage range for BLDC systems is 12V. With the inclusion of 48V rails to these systems, it is important to understand the resulting effect on MOSFET power losses. It is crucial to manage the sources of power loss in order to mitigate operating heat and preserve battery charge.

This application note discusses the new system level considerations when transitioning to 48V, including conduction losses, switching losses, EMI, and more. For all further examples and calculations, a 960W power level is used for both 12V and 48V, meaning 80A at 12V and 20A at 48V.