Other Parts Discussed in Thread: UCD7242
Setup:
Two UCD9248#s, each controlling 2 dual bucks UCD7242#s with there own AGND.
So in total 4 rails per controller using DPWM 1/2/3/4 A only.
Both controllers are on the same PMBus
All IC#s are powered from a 12V rail.
All rails are programmed for individual voltages via the TI GUI “Fusion Digital Power Designer”
Problem:
When powering up the PG pin is toggling at on UCD9248 and is not seen on PMBus.
The other UCD9248 is ok. Both UCD9248#s Reset pins are high.
System Monitor is set to “CONTROL PIN ONLY” and rails are activated via USB Control Lines from High to Low.
Setting it back to High sets the PG pin to expected state for both UCD9248#s.
After this the UCD9248 which was not seen before on PMBus is now present.
Setting now in System Monitor “OPERATION ONLY” for the “problem” controller works for rail 2 and 3 using “Operation Cmd” “On”.
When setting rail 1 or 4 to “On” causes PG toggling again and the controller is lost on PMBus and the GUI says “disconnected from USB adapter”
Do you have any idea what could be the reason?
Thanks in advance.
Mat
