SLVAFZ3 December   2024 DRV8161 , DRV8162 , DRV8350 , DRV8350F , DRV8353 , DRV8353F

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2System Power Requirements
  6. 3Motor Current and MOSFET Selection
    1. 3.1 How Does a BLDC Motor Driver System Work?
    2. 3.2 Motor Current and QG Value Relation
    3. 3.3 Role of a Motor Driver
    4. 3.4 Can my MOSFET be Driven or Commutated?
      1. 3.4.1 Example 1 – Medium Power (4.8kW – 48V × 100A)
      2. 3.4.2 Example 2 – High Power (19.2kW – 48V × 400A)
  7. 4Motor Driver Specifications to Consider
    1. 4.1 DRV8353 - Internally Generated Gate Drive Supply
    2. 4.2 DRV8161/DRV8162 – Externally Generated Gate Drive Supply
  8. 5Advantages of TI’s BLDC Drivers With Smart Gate Drive
  9. 6Maximum Source and Sink Current and QGD
  10. 7Older Designs
  11. 8Summary
  12. 9References

2 System Power Requirements

Most emerging robotics applications run on a 48V rail and with power requirements varying from few 10s of watts in small robots to 10s of kilowatts in cobots used to lift large payloads.

The load being moved can range from a few kilograms to a few hundreds of kilograms and the designer can translate this value to the power needed from the bus supply through the MOSFETs.

The formula shown in Equation 1, states how power is directly proportional to voltage and current.

Equation 1. P = V × I

The motor voltage is the rated voltage of the motor and can be determined by the system’s bus voltage supply. The motor current can be determined by the load that is being driven by the motor. The designer need to verify that the motor is able to handle the current required by the application.

A common concern when selecting a motor driver for high power application is whether or not the gate driver is able to drive the MOSFETs chosen for the application. The following sections can explain how BLDC motor driver designs work and cover two example MOSFETs for different power ranges that can be driven by TI’s BLDC gate drivers.