Glad you've got it working... now you know why they make drivers
And good points on heatsinking. And some good caveats on Real World versus Data Sheet.
If you have genuinely found that a 'good' device cannot operate at specification you should report it to the manufacturer. Are you confident enough to say to the manufs "You've got it wrong."?
But you have to be careful.
Are you driving the gate at the voltage defined in the manuf's test ciruit? (10V in their spec sometimes pulsed @XHz @Y% Duty).
Are you using the correct capacitors on the driver?
Is your PCB layout and track geometry good?
Is your load reactive?
When you say 'continuous' do you mean DC or a steady continuous PWM?
There are numerous things that need to be mastered to get the best out of a device and the manufs have this knowledge and probably do the measurements when the wind is blowing in the right direction
70A down to 21A is a long way down... I'm genuinely surprised that, under the correct conditions, that it is that much different.
And pulse swich speed IS important. And that is affected by your gate drive quality.
Anyway, bottom line. Your project works and doesn't explode. Good stuff.
EDIT: Oh, sorry, some of mine has crossed with BBs.
And good points on heatsinking. And some good caveats on Real World versus Data Sheet.
If you have genuinely found that a 'good' device cannot operate at specification you should report it to the manufacturer. Are you confident enough to say to the manufs "You've got it wrong."?
But you have to be careful.
Are you driving the gate at the voltage defined in the manuf's test ciruit? (10V in their spec sometimes pulsed @XHz @Y% Duty).
Are you using the correct capacitors on the driver?
Is your PCB layout and track geometry good?
Is your load reactive?
When you say 'continuous' do you mean DC or a steady continuous PWM?
There are numerous things that need to be mastered to get the best out of a device and the manufs have this knowledge and probably do the measurements when the wind is blowing in the right direction
70A down to 21A is a long way down... I'm genuinely surprised that, under the correct conditions, that it is that much different.
And pulse swich speed IS important. And that is affected by your gate drive quality.
Anyway, bottom line. Your project works and doesn't explode. Good stuff.
EDIT: Oh, sorry, some of mine has crossed with BBs.