SLVAFZ0 November   2024 DRV8161 , DRV8162

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Three-Phase Gate Driver
    1. 2.1 Architecture
    2. 2.2 Layout Considerations
      1. 2.2.1 Advantages
        1. 2.2.1.1 MCU to DRV Signal Routing
        2. 2.2.1.2 Component Reduction
      2. 2.2.2 Challenges
        1. 2.2.2.1 MOSFET Placement
    3. 2.3 Typical Applications
  6. 3Half-Bridge (Single Phase) Gate Driver
    1. 3.1 Architecture
    2. 3.2 Layout Considerations
      1. 3.2.1 Advantages
        1. 3.2.1.1 MOSFET Placement
        2. 3.2.1.2 Independent Control
        3. 3.2.1.3 Ease of Replacement
      2. 3.2.2 Challenges
        1. 3.2.2.1 Longer Routing Between Gate Driver and Micro Controller
        2. 3.2.2.2 Additional Component Requirements
    3. 3.3 Typical Applications
  7. 4Summary
  8. 5References

Abstract

Brushless DC motors are three-phase motors that are driven through electrical commutation. Voltage applied to the stator coils generate magnetic field which interacts with the rotor magnetic field. Interaction between these two fields causes the rotor to spin. The inputs for the commutation come from the controller and are scaled through a power stage to send power to the motor phases. The power stage for driving the motor consists of turning on or off the MOSFET half-bridges per phase. A motor driver is a power converter that switches the MOSFET based on several PWM modulation techniques. Modulated PWM voltage is applied to the BLDC motor to control speed, torque and position of the motor

The leading implementation of motor drivers in the market, can be split into two categories based on architecture for the purposes of this technical report.

  1. Three-Phase BLDC Drivers
  2. Half-Bridge Drivers

This application note includes the key differences and pros and cons for each architecture. Three-phase architecture offers advantages with more half bridge integration making final implementation more straight forward with one package but faces challenges in signal integrity. Whereas using three half bridges require more local passives but offer flexibility in MOSFET placement, thereby, improving signal integrity and reducing effects of trace inductance.