TMS320F28377D: High Resolution Frequency Sync when driving high-speed full bridge

Ted Huh

Team,

When I use HRPWM to drive full bridge, I need to sync 2 PWMs. However, sync signal is generated on system clock, not high-resolution edge. when I need to change the PWM frequency often, for example once in a 8 period, due to sync signal is not generated on high-resolution edge, there should be timing error on 2nd PWM module.

PWM frequency is changing between 700kHz~900kHz. How should I make perfect sync in this situation?

Regards,

Ted

over 7 years ago

0 Nima Eskandari over 7 years ago

TI__Guru 52040 points

Ted,

Allow me some time to look into this.

Nima

0 Nima Eskandari over 7 years ago in reply to Nima Eskandari

TI__Guru 52040 points

Ted,

It is correct that you cannot sync two channels based on the high-res edge. You can only sync them on the non high resolution edge. With that said if you only sync once, they will be extremely close. If you continuously sync there will be some jitter. So to answer your question there is no perfect sync when using two HRPWMs. You will sync on the PWM edge and the HRPWM signals will be extremely close.

Here is another links to study:
e2e.ti.com/.../62564

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C2000 microcontrollers forum

TMS320F28377D: High Resolution Frequency Sync when driving high-speed full bridge