DC motor H bridge current waveform

[anotherbrick]

hi dear forum members

my question in the picture

thank you

 

[Easy peasy]

Let us hope the other 100k resistors you have not corrected in the new picture are not 100k any more ?

for your mosfets, 0.0046 ohm x 1.5 x 30^2 = 6.21 watts, / 2 = 3.1 watts each, as on half the time

this is 12 - 15 watts for all 4 fets, perhaps surprisingly you need a lot of heatsink to keep the Trise down at 15 watts, especially if the ambient is 30 -40 deg C

It appears your simple plate is not up to the job, so you need a proper heatsink, if you double up the mosfets you will get to 7 watts ( + sw losses ) which will likely be a lot better.