SLVSHN2 July 2024 DRV8962-Q1
PRODUCTION DATA
The total power dissipation in each half-bridge can be calculated as -
PHB = PHS + PLS = [RDS(ON) × IL2] + [((2 x VD x tD) + (VM x tRF)) x IL x fPWM]
Where,
For DRV8962-Q1, it is typically 53 mΩ at 25 °C, and 80 mΩ at 150 °C.
tRF = Output voltage rise/ fall time
For DRV8962-Q1, the rise/fall time is either 70 ns or 140 ns
For DRV8962-Q1, it is 1 V
For DRV8962-Q1, it is 300 ns
So, total power dissipation in the DRV8962-Q1 is -
PTOT = n × PHB + PQ
Where n is the number of half-bridges switching at the same time, and PQ is the quiescent power loss.
For this example, let us assume -
All four half-bridges are switching
VM = 24 V
IL = 3 A
Ambient temperature (TA) = 25 °C
tRF = 70 ns
Input PWM frequency = 20 kHz
When the VCC pin is connected to an external power supply, the quiescent current is 4 mA, and therefore PQ will be (24 V x 4 mA) = 96 mW.
PHB = [53 mΩ × 3 2] + [((2 x 1 V x 300 ns) + (24 V x 70 ns)) x 3 A x 20 KHz] = 0.614 W
PTOT = (4 x 0.614) + 0.096 = 2.552 W