TIDM-02000: When should PCMC CMPPS Ramp Max value be set?

Chen

Figured this out myself. Thank you for clarifying anyway.

I have another question regarding the max value of ramp. Why is PSFB_IRAMPMAX_SET_RATIO set to 32768? Shouldn't it be 65536?

CMPSS_O_RAMPMAXREFS is a 16 bit register and per the design guide, the most significant 12 bits register are fed to the DAC and the other 4 bits scale the slope.

Setting PSFB_IRAMPMAX_SET_RATIO to 32768 would set the trip limit to half the actual reference. This is also what I noticed during testing and changing PSFB_IRAMPMAX_SET_RATIO to 65536 fixed it.

Also, we need to implement an output current control loop. Are there any references for PCMC with output current control instead of voltage control?

Chen

Waiting for your response on my previous comment.

Also, how is the ADC oversample PWM base synced with the leading leg PWM?

Hi Ashwin,

Sorry for the late reply due to holiday and other staff.

Ashwin Ramanujam said:

Shouldn't it be 65536?

It should be 65536. I think we have fixed it in our latest solution.

Ashwin Ramanujam said:

Are there any references for PCMC with output current control instead of voltage control?

Outer average current loop with internal Peak current loop control? I am not aware it.

Ashwin Ramanujam said:

how is the ADC oversample PWM base synced with the leading leg PWM?

Sorry, I don't get your question here. 

Regards,

Chen