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

3.4 Can my MOSFET be Driven or Commutated?

To determine if the MOSFET chosen to drive a load can be driven by the motor driver, the designer needs to consider the average gate current that the gate driver is able to supply. This is the average current that can be consumed while switching the MOSEFT and is dependent on how often you switch per cycle and how many MOSFETs get switched.

Factors to consider:

  1. Number of MOSFETs being switched (based on commutation Trapezoidal vs FOC)
  2. PWM Switching Frequency
  3. Gate Charge, Qg, of the MOSFET
Equation 3. IAVG=# of MOSFETs Switching × PWM Frequency × QG