UCC5390: No output showing

Hi Mohammad,

UCC5390 has CMOS input thresholds, which means the input rising and input falling thresholds are proportional to VCC1.

See section 8.11 Electrical Characteristics, of the datasheet.
Positive-going input threshold is 0.55*VCC1 typ, 0.7*VCC1 max.
VCC1 = 12V -> rising threshold = 6.6V typ, 8.4V max

Since you're using a DSP, I would recommend you lower VCC1 from 12V to 3.3V, if it's possible at least. Otherwise, you will need to level shift your PWM signal between the DSP and UCC5390.

If this helped answer your question, could you please press the green button? If not, feel free to keep asking questions.

Thanks,
John

Hi Mohammad,

You can use a straightforward circuit, like this to level shift the signal from 3.3V to 12V. There are also many dedicated level shifting ICs available, depending on how you prefer to integrate the level shifter into your test setup.

If this helped answer your question, could you please press the green button? If not, feel free to continue asking questions.

Thanks and best regards,

John

Hi Mohammad,

These can be small FETs, they mainly need low gate charge and low Vth so they can be driven by your DSP. They also need to handle 12V Vds, so preferrably a 20V or 30V FET.

Thanks,
John