9.2.1.2.1 External MOSFET Support
The DRV8340-Q1 MOSFET support is based on the capacity of the charge pump and PWM switching frequency of the output. For a quick calculation of MOSFET driving capacity, use Equation 4 and Equation 5 for three phase BLDC motor applications.
Equation 4. Trapezoidal 120° Commutation: I
VCP > Q
g × ƒ
PWM
where
- ƒPWM is the maximum desired PWM switching frequency.
- IVCP is the charge pump capacity, which depends on the VM pin voltage.
- The multiplier based on the commutation control method, may vary based on implementation.
Equation 5. Sinusoidal 180° Commutation: IVCP > 3 × Qg × ƒPWM