What is the maximum power dissipation of driver DRV8432DKD if i take current in parallel mode of 14A (7A from each half bridge).How you reach to thermal resistance of 4.43 of aluminium heat sink of
HEATSINK ALUMINUM 35x80x38mm 40mm PITCH.Can you tell me in brief.My calclution is not maching with this data can you please guide me.
Here are the my calculation
max junction temperature=125 deg C.
max ambient temperature=50 deg C
power dissipation in driver DRV8432dkd is calculated as
voltage drop accross each mosfet at 7amp current is 1.2V P=1.2x7=8.4.When i am using in parrallel mode.4 half bridges will be on.Total power is 8.4x4=33.4~35W (i have taken as save case 40W)
thermal resistance of thermal paste is taken as 0.03 deg C/W
from above data and using following equation
θJA is thermal resistance of junction to ambient.
θJC is juntion to case
θCS is case to sink
θSA is sink to ambient
θJA Total= θJC +θSA + θCS
thermal resistance of heat sink is coming outt to be 0.945 deg C/W
But it is not justified by the data mention in ti site.Can you tell where i am going wrong.
Waitng for your response.
With Regards
Vipin Patel
CEDT
IISc Bangalore
.
