TMS320F28069: Deadband - Active high complementary PWM, please explain

Hello Niclas,

It may appear that both waveforms you're referring to have rising edge delay, but really the lower signal has falling edge delay applied to it, and then the signal is inverted. Selecting AHC for POLSEL inverts the signal on the falling edge delay path but not on the rising edge delay path. Notice the inverting functionality in figure 3-31 above DBCTL[POLSEL].

This video may be useful in understanding all the parts of the dead-band submodule: 

https://training.ti.com/c2000-enhanced-pulse-width-modulator-epwm-dead-band-submodule

Thank you,

Luke

Ok. Thank you. Can I also ask how to implement AHC PWM together with Peak Current Control using the internal analog comparator?

Hi Niclas,

Are you asking how to implement AHC into the code example on page 325 of the F2806 user guide? Otherwise could you provide more explanation on the design you're trying to implement?

Thank you,

Luke

I am going to make a peak current control for a phase shifted full bridge converter, as in TIDU248. Is it possible to combine the AHC with the on-chip comparator to control the duty cycle? Maybe there is a better way of doing it

Here is the PWM diagram from TIDU248. 4 PWMs are used, and deadband is needed. And I want to use peak current control with the internal comparator: 

As I understand it, Q2 and Q3 above will use the internal comparator to switch off when the current reference is reached. But then (after a deadtime) the other PWM needs to get high until the current reaches the reference again. How can I make this happen?

Hi Niclas,

Please take a look at figure 3-4 of TIDM-02000 user guide which contains how we setup deadband.

Regards,

Chen