JAJST19 February 2024 DRV8262-Q1
PRODUCTION DATA
For a H-bridge with high-side recirculation, power dissipation for each FET can be approximated as follows:
PHS1 = RDS(ON) × IL2
PLS1 = 0
PHS2 = [RDS(ON) × IL2 x (1-D)] + [2 x VD x IL x tD x fPWM]
PLS2 = [RDS(ON) × IL2 x D] + [VM x IL x tRF x fPWM]
Where,
For DRV8262-Q1 in dual H-bridge mode, it is typically 50 mΩ at 25 °C, and 85 mΩ at 150 °C.
tRF = Output voltage rise/ fall time
For DRV8262-Q1, the rise/fall time is 110 ns
For DRV8262-Q1, it is 1 V
For DRV8262-Q1, it is 300 ns
Substituting the following values in the equations above -
VM = 24 V
IL = 4 A
RDS(ON) = 50 mΩ
D = 0.5
VD = 1 V
tD = 300 ns
tRF = 110 ns
fPWM = 20 kHz
The losses in each FET can be calculated as follows -
PHS1 = 50 mΩ × 42 = 0.8 W
PLS1 = 0
PHS2 = [50 mΩ × 42 x (1-0.5)] + [2 x 1 V x 4 A x 300 ns x 20 KHz] = 0.448 W
PLS2 = [ 50 mΩ × 42 x 0.5] + [24 x 4 A x 110 ns x 20 kHz] = 0.611 W
Quiescent Current Loss PQ = 24 V × 5 mA = 0.12 W
PTOT = 2 x (PHS1 + PLS1 + PHS2 + PLS2) + PQ = 2 x (0.8 + 0 + 0.448 + 0.611) + 0.12 = 3.84 W