UCC24612: First pulse

Hello,

The UCC24612 determines the inhibition period of proportional control based on the conduction time of the previous cycle, but how does it determine the first pulse?

The first gate drive is initiated when Vds goes below VTHVGON.  VTHVGON = -240 mV typical.

When Vds goes greater than - 2 mV on the first cycle the device records the conduction time of the first switching cycle. 

Does it control to Vthreg-50mV after TONblank without an inhibition period?

When Vds is less than Vthreg-50mV the gate drive will be at its maximum.

Once Vds is -50 mV the gate drive voltage will be adjusted to maintain a Vds of -mV.   This done by adjusting the Vds impendence.

The controller will only adjust Vg after TONblank has timed out.

Or does it measure the conduction period without outputting a pulse and use that as the basis for the next pulse?

N/A

Regards,

Hello,

Since there is no information on the first pulse the device depends on the Vds voltage to set the gate drive voltage.  The proportional gate drive will still work even for the first pulse.

Regards,