TMS320F28378S: Question about PWM Issue.

David Kim2

Part Number: TMS320F28378S

We are having issues in PWM generations as I have mentioned in the PDF file (I am attaching it again for your reference). As mentioned in the pdf file that we are controlling an LLC circuit using a dual mode control (phase shift + VARIABLE Frequency). In phase shift mode after each few cycles there is missing pulse occurring which causing inrush current. Additionally, while moving from phase shift mode to frequency mode we have some issues. Please see the attached file for better understanding.

PWM Issue using TI C2000 EPWM (002).pdf

Thanks

over 1 year ago

0 Allison Nguyen over 1 year ago

TI__Mastermind 24360 points

Hi David,

Thanks so much for the information.

Depending on the phase shifting values and timing, there can be some instances where a missing action qualifier occurs if the syncing jumps over the action qualifier event. This can result in longer high or low pulses since the action is missed. I helped address this recently in a past thread and there is a way to prevent this from happening. Please have a look and see if this is the case or is similar to what you are experiencing in your setup.

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1312604/tms320f28379d-tms320f28379d-phase-shift-pwm-missing-pulse

Best Regards,

Allison

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F28378S: Question about PWM Issue.