[F28035] Improve the resolution for ePWM

Tien,

How many bits of resolution are you looking for? What is you PWM frequency and System clock frequency?

-Bharathi.

Hi Bharathi,

I'm currently using TMS320F28035 (SYSCLK=60MHz) to calculate and control a power electronic converter.
I did this program using TMS320F28377D (SYSCLK=200Mhz), it gave me so good results, but when I implement it in TMS320F28035, the results get bad, especially the noise problems. I suppose that there are two reasons:
- The execution time is slower
- The TBPRD of ePWM was decreased
I read about the method of frequency dithering for reducing noise.
Could you give me some pieces of advice?

Thank you!

Hi Bharathi,

I am looking for 2 bits resolution enhancement with 100kHz to 200kHz and SYSCLK=60MHz.

Tien,

Since you are already operating (F28035) at the maximum SYSCLK and your PWM frequency is also pre-defined, only option to increase resolution further would be to use HRPWM.
Is there any specific reason why you do not want to use HRPWM?
Other option would be to use a higher frequency device like F28335 - that may not be an option for you.

-Bharathi.

Hi Bharathi,

I don't want to use HRPWM because in my project I use many synchronous PWM channels.
Could you show me the ways to implement PWM frequency dithering technique for F28035?

Hi Bharathi,

It means that with constant SYSCLK and defined frequencies of PWM, I cannot enhance the resolution of PWM, right?

Yeap, thank you so much!