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

2 Power Loss and Thermals in Motor Driver Systems

The BLDC motor converts electrical potential energy into kinetic mechanical energy through electrical commutation of the three phases of MOSFET half-bridges. The MOSFETs delivering power from the battery to the motor are the largest contributors to power loss and thermals in a motor driver system.

Power loss is a critical factor to consider during system design as power loss affects:

User Experience – High heat affects usability and can lead to user discomfort

Device Reliability – High temperature operation can lead to accelerated wear and tear and affect lifetime reliability

Power Efficiency – Decrease battery life, reduce vehicle mileage and increase thermal design challenge

This application note focuses on the two main areas of power loss with MOSFETs: Conduction Losses and Switching Losses.